Geology – Mobile Ranger

Greyhound Rock: Where’s the Hound?

Ranger Lautamo — Wed, 31 Aug 2016 20:00:32 +0000

Does Greyhound Rock look like a hound to you? Photo: Lauren McEvoy/Mobile Ranger

Greyhound Rock is named for the beach’s large rock formation that sits stoically offshore in the crashing waves. Usually, the rock is connected to the beach by a small sand spit that is part of the Greyhound Rock State Marine Conservation Area near Davenport, north of Santa Cruz, California. The rock was given its name by a Santa Cruz pioneer named Thomas Majors who thought it looked like a hound.

Historic photo of Greyhound Rock. Photo: Santa Cruz Museum of Art & History

Today, it’s a bit hard for most people to see the hound. Perhaps, over the decades, the ocean surrounding Greyhound Rock County Beach has eroded away any canine resemblance. If anything, the rock looks like a sleeping alligator from above, and from down on the beach, it just looks like a long mound of layered mudstone. That’s very cool in and of itself, hound or no hound.

Hound, alligator, or chocolate softserve ice cream? You decide. Photo: Lauren McEvoy/Mobile Ranger

Formation of the “Hound”

Greyhound rock is made up of Santa Cruz Mudstone. This is the rock formation that shapes the landscape characteristics of the northern Santa Cruz coast, from the north county line (basically at Ano Nuevo State Park) through to the west side of Santa Cruz. It’s a fairly hard rock type, although its many layers vary in their hardness and how easily they erode. If it were a much more erodible rock or did not have layers, the coastal landscape we see today might be without the many arches and bridges and dramatic sea cliffs with their undulating pocket beaches.

Classic shore platforms and pocket beaches of the Santa Cruz Mudstone. Long Marine Lab. Photo: Julia Gaudinski/Mobile Ranger

The pocket beaches occur where the horizontal layers of the mudstone have fractures or “joints” running roughly perpendicular to the cliffs. The joints are points of weakness, so the waves erode along the joints much faster than the rest of the layer.

Creation of Santa Cruz Mudstone

The Santa Cruz Mudstone was created about 7 – 9 million years ago (late Miocene era) by the settling of fine-grained silts, clays, and silicate remains of billions of single-celled plankton called diatoms. It varies in thickness but has been measured to be 8,900 feet thick in at least one location.

Santa Cruz Mudstone at Waddell Bluffs. Photo: Julia Gaudinski/Mobile Ranger

The sediments accumulated offshore of the ancient (Paleo era) coast in ocean water about 450 – 600 feet deep. The silts and clays came from nearby rivers. Because the amounts coming from each source varied over time, so did the composition of the layers. With time, these sediments became very thick. This is nearly the same conditions we have today half a mile off our coast.

Arches and bridges tend to form in the Santa Cruz Mudstone. Photo: Julia Gaudinski/Mobile Ranger

Hardening to Rock

Over millions of years, thousands of feet of sediment were deposited on top of the Santa Cruz Mudstone sediments. With burial, the sediment warms up and some of the silica from those billions of diatoms dissolves and later turns into cement that binds the particles together. This is called lithification.

During and after lithification, the sediments are also subjected to regional tectonic stresses from huge tectonic plates moving around, which can cause folding and faulting. Thus, the original sediment composition, the degree of lithification, and the amount of tectonic stress combine to determine how hard a rock is and how it will erode. In and around Santa Cruz, the Santa Cruz Mudstone is not very deformed, with just some tilting, jointing, and faulting.

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This piece is part of the Santa Cruz Marine Protected Areas Beaches Tour made possible by the Santa Cruz Collaborative with support from the California Marine Sanctuary Foundation and the Resources Legacy Fund. Download the free app with many tours of the Santa Cruz area and beyond.

Sources
- The Rocks of Santa Cruz’s North Coast: The Mighty Mudstone. Mobile Ranger website.
- "Our Ocean Backyard: Exploring the North Coast,” by Gary Griggs. Santa Cruz Sentinel, August 9 , 2013.
- "Our Ocean Backyard: West Cliff – Stepping Back in Time,” by Gary Griggs. Santa Cruz Sentinel, December 14, 2013.
- California Coastal National Monument. National Conservation Lands, California. U.S. Department of the Interior, Bureau of Land Management website, blm.gov.
- The things you learn on a Coastal Geology Walk at Año Nuevo State Park,” by Ryan Masters, Goat Trails blog. Hilltromper website, October 24, 2014.
- Coast Dairies Property: A Land Use History. Excerpt from "Coast Dairies Long-Term Resource Protection and Use Plan: Draft Existing Conditions Report for the Coast Dairies Property," Section 1.0. In Santa Cruz County History - Places, Santa Cruz Public Libraries website.

Elkhorn Slough: Interface Between Land and Sea

Ranger Gaudinski — Wed, 24 Aug 2016 20:00:40 +0000

Elkhorn Slough with Moss Landing Power Plant in the background. The orange stuff is called dodder (Cuscuta) and is a parasitic plant. Photo: Julia Gaudinski/Mobile Ranger

At Moss Landing, Highway 1 crosses over Elkhorn Slough, one of the largest estuaries in California. Estuaries are places where the sea meets freshwater. They are home to a rich array of plants and animals that can live in this unique habitat. At Elkhorn Slough, the seawater enters the estuary at the harbor mouth directly west of the Highway 1 bridge, and freshwater comes from several sources: the Salinas River; Tembladero Slough, which runs south of Castroville; and upland creeks that feed into both Moro Cojo and Elkhorn sloughs.

Most of the Elkhorn Slough Watershed and the majority of fresh water sources that drain into it. Image: Courtesy of The Elkhorn Slough Foundation

People have lived along the shores of Elkhorn Slough for at least 8,000 years. Successive waves of people have used the slough in different ways, including harvesting shellfish, fishing, hunting, agriculture, and even helping to generate electrical power. Conservation work in the last few decades has protected much of the natural habitat at Elkhorn Slough and has restored areas that were impacted by earlier human uses.

Today, it is one of the largest and most ecologically important estuarine systems in California. It provides habitats for native shorebirds, marine mammals such as sea otters and sea lions, and a wide variety of marine invertebrates. The slough also serves as an important nursery for a variety of fish species.

Moss Landing harbor at Elkhorn Slough. Photo: a7pointstar

Habitats and Wildlife at Elkhorn Slough

Elkhorn Slough tidal habitats encompass extraordinary biological diversity, providing critical habitat for more than 135 aquatic bird, 550 marine invertebrate, and 102 fish species. The slough is also home to sea lions, harbor seals, and California sea otters. More than 200 different bird species use the slough as a resting spot during their annual migrations.

The upland habitats within the watershed include three of the top 10 most imperiled US habitats: freshwater wetlands, coastal prairie, and maritime chaparral. These systems are amazingly diverse, with coastal prairie being the most species-rich grassland in North America.

Several harbor seals rest at a side channel in Elkhorn Slough. Photo: Julia Gaudinski/Mobile Ranger

Along with providing habitat for a diverse range of life, wetlands provide a critical service to the environment. They provide a buffer between land and sea, which protects the water from soil erosion and protects the land by reducing the impact of flooding. As natural filters, wetlands can remove impurities from the water before they enter our streams and oceans.

Estuaries like Elkhorn Slough are among the most threatened ecosystems in California, facing rates of habitat loss between 75 and 90 percent. As a result, a disproportionate number of rare, threatened, and endangered species reside in these areas. In the Elkhorn Slough watershed, two dozen species are included in these categories. Because experts recognize the value of these resources to the country, the National Oceanic and Atmospheric Administration (NOAA) designated areas of Elkhorn Slough as part of the Monterey Bay National Marine Sanctuary and as a National Estuarine Research Reserve.

There are few native oysters left in Elkhorn Slough due to overfishing in the 1920s and habitat burial by sediments. Restoration work is underway. In this photo the growth rates of native oysters are being surveyed. Photo: Elkhorn Slough Reserve

Moss Landing Harbor

The estuary habitats were profoundly affected by the creation of the present day Moss Landing Harbor. In 1947, just two years after the end of World War II, the Army Corps of Engineers dredged a channel through the barrier dunes for a new harbor entrance.

Modern day Elkhorn Slough and Moss Landing Harbor. Photo: US Army Corps of Engineers

World War II had greatly restricted commercial fishing, so when the war was over, development of a commercial fishery in the area became a priority. An opportunity to increase access to fertile fishing areas in Monterey Bay was realized by expanding the harbor at Moss Landing. Today, Moss Landing Harbor is a center for commercial and recreational fisheries, public boating tours of the Monterey Bay and the Elkhorn Slough, kayaking, and world-renowned ocean research facilities.

Elkhorn Slough in 1979 with the expanded harbor. Photo: © Kenneth and Gabrielle Adelman, California Coastal Records Project .http://www.Californiacoastline.org

Changes to the mouth have had ripple effects up the slough. The main slough channel has continued to widen and deepen since it was first dredged decades ago. Scientists at the Elkhorn Slough Reserve are currently studying the long-term effects of these changes.

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Sources
- Elkhorn Slough Tidal Wetland Plan: 150 Years of Human Alterations and Tidal Habitat Change (1870 - Present) . Barb Peichel, Kerstin Wasson, Andrea Woolfolk, and Eric Van Dyke. Elkhorn Slough National Estuarine Research Reserve, February 20, 2005.
- Changes in a California Estuary: A Profile of Elkhorn Slough. Edited by Jane Caffrey, Martha Brown, W. Breck Tyler, and Mark Silberstein. Elkhorn Slough Foundation, 2002.
- What is a Salt Marsh? National Oceanographic and Atmospheric Website.

Waddell’s Wharf: Ordeals of Shipping Lumber from Año Nuevo Bay

Ranger Lautamo — Wed, 03 Aug 2016 20:00:26 +0000

Cove Beach at Año Nuevo State Park. Waddell’s Wharf went out to the sea in the center left of the photo where you see a large clump of trees and the waves are at the highest point on the beach. Photo: Julia Gaudinski/ Mobile Ranger

Over 150 years ago, the coastline at Año Nuevo State Park, between San Francisco and Santa Cruz, California, was home to a bustling lumber industry. Even though the wharf at Cove Beach in Año Nuevo Bay once shipped over two million feet of lumber in just one year, it’s hard to find signs of its existence today. The story of this wharf begins about two miles south of Cove Beach at Waddell Beach, now a popular spot for kite surfers and the coastal entrance to Big Basin State Park. In the 1860s, William Waddell, a failed businessman from Kentucky, built his home, a steam-powered lumber mill, the first of two shipping wharves, and a five-mile tramway here in the canyon that now bears his name.

Waddell Beach, the site of the unsuccessful first Waddell’s Wharf, unknown date. Photo: Santa Cruz Museum of Art & History

The millworkers cut an impressive 20,000 feet of lumber a day at the mill’s peak operation. Waddell had one major problem, though: He didn’t have a way to ship his lumber to the market.

A Tale of Two Wharves

To solve this problem, he began construction of a 1000-foot wharf in 1864. He built it at the mouth of what is now called Waddell Creek. Unfortunately, he hit a layer of bedrock after spending $30,000 ($686,000 in today’s money) and had to abandon construction.

Not to be deterred, Waddell built a second, 700-foot wharf at Cove Beach. Less than a year later, the wharf was washed away in a storm. Waddell replaced it, only to have a large portion washed away again in 1870. It took four men and a horse to retrieve that section.

The Waddell Wharf, circa 1868 at Cove Beach. It shows a newer platform built on top of an older wharf likely damaged in a storm. Photo: Santa Cruz Museum of Art & History

In the center of the photo just past the wooden step, is where Waddell’s Wharf went out to the sea. Photo: Julia Gaudinski/ Mobile Ranger

Cribs built by William Waddell for the rail line that took his lumber to Waddell’s Wharf at Cove Beach. This area later became the foundation of a Santa Cruz County road. Unknown date. Photo: Santa Cruz Museum of Art & History

It Ends with a Bear

On an autumn day in 1875, Waddell went hunting with his dog and the local blacksmith. Near the entrance to a ravine, a grizzly bear attacked him, but his faithful dog jumped into the fray and lured the bear back into the woods.

A rough and tumble with a grizzly by H. Bullock Webster, ca. 1874 – 1880. Image: University of British Columbia

He made it home, but he died five days later from blood poisoning and was buried in the Odd Fellows Cemetery in Santa Cruz. Waddell was one of the last grizzly bear victim fatalities recorded in California before the species went extinct statewide, from hunting, in 1922.

Where to Look for Remnants of the Wharf

A few remnants of the mill and Waddell’s Wharf remain, but you have to know where to look and the last pier has been eroded away from the beach for decades.

The last remaining piling of William Waddell’s Wharf at Cove Beach, January 16, 1977. Photo: Courtesy of Gerald Weber

Many of the wharf timbers were reused to build the dairy and horse barn at Año Nuevo State Preserve, which are now the visitor center. Boilers from the mill now function as culverts at May Creek and an unnamed stream. And about two-thirds of the way up Waddell Canyon, you can still find four posts from the five-mile tramway.

Timbers from Waddell’s Wharf were salvaged and reused by Edwin Dickerman to build a dairy and horse barn in 1881. These buildings and their supporting wharf-derived beams are now part of the visitor center at Año Nuevo State Preserve. Photo: Mike Merritt

These leftover pieces are reminders that Highway 1 was once a wild place where pioneers tried to stake their claims on the land, only to be knocked back again and again by the forces of nature. Today, we try harder to coexist with these wild places, study them, explore them, and protect them for many generations to come.

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Sources
- The Story of William Waddell & The Waddell Mill, by Mike Merritt.

Santa Cruz’s Nuclear Power Plant That Almost Was

Ranger Gaudinski — Wed, 27 Jul 2016 20:00:53 +0000

Aerial image of El Jarro Point in 1993. This is area is about 3.5 miles south of Greyhound rock. The buildings in the center-top portion are what is now Swanton Berry Farms. Photo: © Kenneth and Gabrielle Adelman, California Coastal Records Project .http://www.Californiacoastline.org

Greyhound Rock lies right next to one of the major faults within the San Gregorio Fault Zone. This fact might be no big surprise in earthquake-prone California, but what is startling is how ridiculously close we came to building a huge nuclear power plant right on top of this active fault zone.

In 1969, Pacific Gas and Electric (PG&E) announced it had leased 6,800 acres of Coast Dairies and Land property and intended to build a 6,000-megawatt-generating nuclear power plant at El Jarro Point, a wide marine terrace between Scott Creek Beach and Davenport Landing. The plant would have stood approximately where Swanton Berry Farm is now and required a major rerouting of Highway 1.

Geologist Gerald Weber standing in the field where El Point Nuclear Power Plant was to have been built. Photo: Julia Gaudinski/Mobile Ranger

Creation of the plant was inadvertently derailed when a University of California, Santa Cruz (UCSC) geology graduate student named Jerry Weber took a walk on nearby Cove Beach in 1973. Weber noticed that a recent storm had eroded the sea cliff and revealed a large active fault in the cliff face. According to Weber:

“It is a classic exposure of fault movement. The fault had been completely covered by vegetation for probably hundreds of years. If not for the El Niño storms of 1972 and 1973, no one would have ever noticed it.”

The entire zone between the two black arrows is the Frijoles Fault at Año Nuevo/Cove Beach. Notice that it is a “zone” about 70 feet wide. To find it when you go to our Año Nuevo/Cove Beach stop, look for the trees and the slumped area. If you see the dark tilted layer in the cliffs, above the right-most arrow, you know you have found the fault. Image: Julia Gaudinski/Mobile Ranger

In the 1970s, the San Francisco Bay Area was well-known for earthquakes along the San Andreas Fault, of course. But the San Gregorio Fault, which extends from San Francisco to south of Santa Cruz all along the coast, was just being discovered and mapped. Weber’s work was crucial in detailing the faulting around Año Nuevo State Park and Greyhound Rock.

Faults in the San Francisco Bay Area and Santa Cruz coast region. Image: Courtesy Gerald Weber

By 1971, a passionate group of people was already on the move to stop the nuclear power plant at El Jarro Point. In September 1971, the Santa Cruz County Board of Supervisors voted 3 to 2 for a moratorium “in principle” on a permit for the plant. But it was really Weber’s discovery of the Frijoles Fault and other faults in the San Gregorio Fault Zone at Cove Beach that stopped the El Jarro Nuclear Power Plant dead in its tracks.

For a nuclear power plant to be approved, there can be no nearby active faults and, in geologic terms, “active” means a surface rupture within the last 10,000 years. By using radiocarbon dating of plant remains at the base of the cliffs at Cove Beach, Weber was able to prove clear movement within the San Gregorio Fault Zone at Año Nuevo/Cove Beach in the last 10,000 years.

A map of the many faults in this area. The fault exposed at Greyhound Rock is still not well mapped. Image: Created by and courtesy of Gerald Weber

Faults from the San Gregorio Fault Zone continue north and south and can be seen in the beach cliffs at Greyhound Rock. Greyhound Rock itself is not faulted.

These cliffs at Greyhound beach clearly show fault movement. The two black arrows point to the most obvious places where rocks have slid past each other. There are likely two other faults in this area two but they are a bit harder to see. Image: Julia Gaudinski/Mobile Ranger

The San Gregorio Fault is long and composed of many parallel faults. At Año Nuevo/Cove Beach, Weber has mapped at least six faults in a zone that is a mile wide. In fact, when you think of faults and earthquakes in general it’s best to think of fault zones or even a system of faults.
Indeed, the San Gregorio Fault Zone is one part of what is now referred to as the San Andreas Fault System because there are several faults involved, including the Hayward and Calaveras Fault Zones and the San Gregorio Fault Zone.

One way to cope with the threat of earthquakes: poke fun at the threat with a t-shirt!

As you enjoy the California coast, keep in mind that it could start moving and shaking at any time. The San Gregorio Fault Zone has moved in the last 10,000 years and it will move again. We just don’t know when. Geologist Gerald Weber admits that he hopes the San Gregorio Fault Zone, which he spent much of his life laboriously mapping, might show some modest sign of movement while he is still alive.

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Sources
- The Geology from Santa Cruz to Point Año Nuevo, with the San Gregorio Fault zone and Pleistocene Marine Terraces. Gerald E. Weber and Alan O. Allwardt. University of California, Santa Cruz
- Personal communication with Dr. Gerald (Jerry) Weber, Lecturer Emeritus University of California, Santa Cruz, Geologic Consultant. May and June 2016.

Caves and the Moving Lighthouses of Lighthouse Point

Ranger Gaudinski — Thu, 16 Jun 2016 02:50:57 +0000

Modern day Lighthouse Point showing the Purisima Formation and the Mark Abbott Memorial Lighthouse, which was built in 1967. Photo: Julia Gaudinski/Mobile Ranger

Lighthouse Point in Santa Cruz, California, is surrounded by world class surf spots and amazing views. It’s named for the lighthouse built to commemorate a local boy who went surfing and never came back. The lighthouse is a museum of local surf history, and the whole area has grown to be a special nexus of expression for the Santa Cruz surfing community. So it seems fitting, even though unfortunate, that this gateway to the ocean’s beauty and power is threatened by the power of the ocean.

Its Beach with Lighthouse Point in the background. Photo: Julia Gaudinski/Mobile Ranger

Lighthouse Point is composed of a particularly resistant part of the Purisima Formation. In general, the Purisima erodes fairly easily. For this reason, the ocean was able to cut landward and create the Monterey Bay. However, Lighthouse Point and a few other resistant headlands, including San Lorenzo Point and Pleasure Point, have withstood the ocean’s erosive force. Lighthouse Point actually protects Monterey Bay’s northern beaches from much of the wave energy they would otherwise get from the dominantly northwest waves. Even so, Lighthouse Point is not immune to wave erosion.

The lighthouse circa 1888. Photo: Courtesy of the Santa Cruz City-County Library System

Original Lighthouse Had to be Moved

The original lighthouse was built in 1869, close to the edge of the cliff. In 1878, less than 10 years later, a letter was sent to the Lighthouse Board noting that three large caves (all over 50 feet long and 50 feet wide) penetrated the point, and the largest extended to within 12 feet of the lighthouse.

To preemptively save the lighthouse from potential catastrophic cliff erosion, the Lighthouse Board ordered it to be picked up and moved 300 feet inward. Thus, from 1879 to 1948, the lighthouse was located on the north side of what is now West Cliff Drive.

Aerial view of Lighthouse Point circa 1941. You can see the beacon and the old lighthouse on the north side of West Cliff Drive. Photo: By Ed Webber, used courtesy of Frank Perry

A Long Run Comes to an End

In 1939, the Coast Guard assumed responsibility for all of the nation’s lighthouses. Shortly thereafter, the Coast Guard installed an automated beacon on top of a white wooden tower and decommissioned Santa Cruz’s lighthouse. The beacon was about 20 feet north of the current Mark Abbott Memorial Lighthouse. The light from the beacon was less than half as bright as that from the lighthouse. Despite a vibrant shipping past, by 1930, due to roads and railroads, Santa Cruz no longer had much shipping traffic. Therefore, the beacon was bright enough to be seen only by local fishing boats.

The lighthouse facilities were used briefly during World War II to house 200 soldiers stationed there during the war. After WWII, however, the lighthouse was not serving a particular purpose for the Coast Guard, so it was demolished. From 1948 until 1967, Santa Cruz had no lighthouse. There was just a beacon with a light so weak that local fisherman complained it couldn’t be distinguished from the car headlights on West Cliff Drive.

Aerial view of Lighthouse Point in 1957. The beacon stands alone. The only traces of the original lighthouse are the cypress trees that outline where it stood from 1879 to 1948. Photo: Used courtesy of Frank Perry

The New Lighthouse

The beacon might still be the only light here today if not for the tragic death of a local boy named Mark Abbott. On a Sunday morning in February, 1965, Mark went to the beach with his friends, went body surfing, and never returned. Mark’s parents, Chuck and Esther Abbott, were able to turn their grief from losing a child into something positive for the community: a new lighthouse at Lighthouse Point. The Abbotts made sure that the lighthouse honored even more than their son. A bronze plaque inside the lighthouse reads:

“This lighthouse is further dedicated to all our youth whose lives, through fate or misadventure, are terminated before realizing their true potential. May their spirits find new dimension in the unknown horizons that await us all.”

Same Cave Problem

The brick remains of the original lighthouse built in 1869 lie just a few hundred feet toward the ocean from the Mark Abbott Memorial Lighthouse.

Brick remnants of the original 1869 lighthouse (center left). The round brick shape (center right) was a cistern used for collecting rainwater from the lighthouse roof. Photo: Julia Gaudinski/Mobile Ranger

In 1980, one of the caves that undermined the original lighthouse was plugged with concrete because it threatened to undermine the Mark Abbott Memorial Lighthouse. Unfortunately, the plug did more harm than good, because it deflected waves upward, increased erosion of the upper cliff, and exposed the brick foundation of the original lighthouse site. It eventually washed out in 2000.

Filling the caves under Lighthouse Point in 1980. Photo: By and courtesy of Frank Perry

During the El Niño storms of 1982–83, waves eroded the sea cliff to within 10 feet of the Mark Abbott Memorial Lighthouse. A new concrete retaining wall was built in the 1990s, and the walkways and fences in this area are constantly being moved landward. Two caves still remain: one just to left of lighthouse, facing south (the one that had the concrete plug) and another on the west side, facing southwest. That second one is quite deep and extends almost to the lighthouse.

The cave filled in 1980, which is still eroding. Photo: Julia Gaudinski/Mobile Ranger

A cave in the Purisima Formation, which is undercutting modern day Lighthouse Point on the west side of Santa Cruz. Photo: Julia Gaudinski/Mobile Ranger

A crane placing rip rap rocks near Steamer Lane in 1981. Photo Courtesy of and by Frank Perry

Much of West Cliff Drive has been armored with rip rap (1– to 2–ton boulders placed in a group) and sea walls to try to prevent erosion from cutting back the coastline. Such protections at Lighthouse Point certainly conflict with its natural beauty and surf. But the caves are there and, at some point, hard decisions about additional armoring of Lighthouse Point versus saving the lighthouse will have to be made. Perhaps it could be moved back across West Cliff Drive?

A view from the Santa Cruz Mountains to the eroding coast along West Cliff Drive in 2010. Photo: © Kenneth and Gabrielle Adelman, California Coastal Records Project www.Californiacoastline.org

Further Information

Lighthouse Point: Illuminating Santa Cruz, by Frank Perry. Otter B Books, 2002. Available at the Santa Cruz Museum of Natural History, Santa Cruz Surfing Museum, and Natural Bridges State Beach Visitor Center.
Santa Cruz historian Frank Perry’s website.
Santa Cruz Surfing Museum. Located at Lighthouse Point, the museum is open Wednesday through Monday, 10 am to 5 pm, July 4 through Labor Day and Thursday through Monday, 12 noon to 4 pm, the rest of the year.
Santa Cruz Museum of Natural History. Located at 1305 East Cliff Drive, the museum is open Wednesday through Sunday, 10 am to 5 pm, during summer (Memorial Day through Labor Day) and Tuesday–Saturday, 10 am to 5 pm, the rest of the year. Call 831.420.6115 for more information.
Lighthouse Friends website.
The Huge Boulders Along the Santa Cruz Shoreline: A Common Coastal Story. Mobile Ranger blog.

Take the Self-Guided Mobile Tour

This piece is part of the West Cliff Drive Tour. Download the free app with many tours of the Santa Cruz area and beyond.

Sources
- Lighthouse Point: Illuminating Santa Cruz, by Frank A. Perry. Otter B Books, 2002.
- Living with the Changing California Coast, by Gary B. Griggs, Kiki Patsch, and Lauret E. Savoy. University of California Press, 2005.
- Personal communication with Frank Perry, Historian, Santa Cruz County, February 2012.
- Personal communication with Gary Griggs, Distinguished Professor of Marine Sciences, University of California Santa Cruz, February 2012.

Surf’s up! Paleo Style

Ranger Gaudinski — Thu, 21 Apr 2016 20:00:47 +0000

The Wave (Coyote Buttes). Vermillion Cliffs, Arizona. Photo: Lobineau

Have you ever ridden a sand wave? Chances are you probably didn’t ride this one. It’s not at Mavericks, and it’s 200 million years old.

Originally a sand dune up to 60 feet high, this wave was part of a vast sand-blown desert on the super continent of Pangea. The desert was much bigger than the modern Sahara and was part of a massive and sinking basin that received sediment from areas as far as the ancient Appalachian Mountains. Known today as “The Wave,” it’s located in the Coyote Buttes of the Paria Canyon-Vermilion Cliffs in Coconino County, Arizona.

How Ancient Winds Formed The Wave

Large dunes require strong winds. The Wave has layers that record the changing winds, which brought sand from different directions. The rhythmic and cyclic alternating laminae represent periodic changes in the prevailing Paleo era winds, which pushed the huge sand dunes back and forth across the massive desert.

Over time, more sediment came into the basin via a huge ancestral river system on the scale of the Mississippi. After being covered by other sediments, the dunes solidified into Navajo Sandstone. If you have been to the Grand Canyon, or just about anywhere else in the Colorado Plateau, you have probably seen the Navajo Sandstone. To give you an idea of the amount of sand in the Navajo Sandstone: It’s about what the modern day Mississippi River would put out in about 10 million years of flow!

The Wave close up. Photo: Peter Fitzgerald

After another 200 million years of first burial and then uplift, erosion has uncovered and exposed the Wave. The thin ridges and ribbing are primarily from differential erosion of these layers by the wind. However, water has also played a part. Vertical movement and precipitation of iron and manganese within ancient water tables probably created the Liesgang bands, which are the alternating ribbons of red, orange, and pink that make The Wave so visually appealing.

The 1996 release of the German nature documentary “Fascinaztion Natur” created a huge influx of European tourists that hasn’t stopped. Access has since been restricted to only 20 hikers a day to preserve the natural rock formation and prevent overcrowding. These days, you need to apply for the required permits four months in advance. So if you want to check out these Paleo dunes, plan ahead!

Sources
- Liesgang rings (geology). Wikipedia. Accessed January 27, 2014.
- Navajo Sandstone (in Glen Canyon Group). Geological Tour Guide, Capitol Reef National Park & Surrounding Areas. University of Utah.

Mitchell Cove: Erosion of a Sea Stack

Ranger Gaudinski — Thu, 24 Mar 2016 12:30:49 +0000

Mitchell Cove beach, along West Cliff Drive in Santa Cruz, California, has lost its stack. Its iconic rock tower, or sea stack to be more precise, is now merely a rock as result of constant coastal erosion. We hope you enjoy the time series photos (above) that span the time between late 2011 to early 2016.

If anyone has other photos to contribute from the same location that fill in the time series, either forward or backward in time, please email them to julia@mobileranger.com, and we will update this page. Earlier, the sea stack was a continuous part of the cliffs, so it would be great to see photos of that era.

Update October 29, 2016: Several people have contributed photos (thank you) and they are denoted with an asterisk after their name.

Take the Self-Guided Mobile Tour

This piece is part of the West Cliff Drive Tour. Download the free app with many tours of the Santa Cruz area and beyond.

Bonny Doon Beach: Railroads and Oil

Ranger Gaudinski — Thu, 03 Mar 2016 14:30:26 +0000

Dramatic sea cliffs of Santa Cruz Mudstone at Bonny Doon Beach. Photo: Julia Gaudinski/Mobile Ranger

California’s Bonny Doon Beach is home to wide-open sands, a creek that runs through it, and even a clothing-optional section to the right of the chunk of Santa Cruz Mudstone where there used to be a natural bridge. It is also has a few features that tell of the areas railroad and oil exploration history.

Aerial view of Bonny Doon Beach circa 1975 when there was still a natural bridge. Photo: From the collection of Paul and Carmen Mulholand via Tom Scully

Doon Beach with its natural bridge circa 1975. Photo: From the collection of Paul and Carmen Mulholand via Tom Scully

Notice the Parking Lot

When you park to go to Bonny Doon Beach, the main parking area hugs right up to huge hill. It so happens this hill is a man-made embankment. The local stream used to run out to sea in the area where the embankment is now. If you have driven between Santa Cruz and Davenport, you might have wondered why you can’t see the ocean very often on the drive. It’s because every creek along the route has an earthen railroad berm or embankment across it that blocks the view. They were all built in the early 1900s, and the embankment at Bonny Doon Beach is a great example of a very big one.

The inland view of the earthen berm on which the railroad tracks sit. The two arrows show the limits of the native bedrock formed from the Santa Cruz Mudstone. In between the arrows is all “fill” for the embankment. Image: Julia Gaudinski/Mobile Ranger

Grandiose Railroad Plans

At the turn of the 20th century, railroads were king and still expanding with easy money from business tycoons of the day. The railroad embankments we see today were originally part of the Ocean Shore Electric Railway, which was begun in 1905 and was to be a grand line from Santa Cruz to San Francisco. It was to have two parallel electric lines to run both passengers and freight and be completed in 1907. Southern Pacific was also building rail to Davenport at about the same time, so there was definitely some hardball and power politics between the two companies.

A More Humble Reality

Fate intervened. The 1906 quake caused huge damages to the northern end of the Ocean Shore line, and their easy funding largely dried up. Construction continued, although money had to be raised from local bonds. Southern Pacific secured the contract to transport cement and materials for the Davenport Cement Plant, and that took away much- needed revenue from Ocean Shore.

Construction of the Ocean Shore line circa 1905. Photo: Collection of Alverda Orlando

The details of how the collaboration ultimately occurred are hard to pin down, but Ocean Shore and Southern Pacific collaborated in building the embankments north to Davenport. The embankments are so wide because they were designed for three tracks (two for Ocean Shore and one for Southern Pacific). They consist of wooden trestles filled in with local material to enable the structures to support the extreme weight of the railway cars loaded with cement.

This 1906 photo shows the wooden railroad trestle that crosses San Vincente Creek, at Davenport, partially filled in. There are many of these filled trestles between Davenport and Santa Cruz, including the one at Bonny Doon Beach. Photo: Collection of Gary Griggs, courtesy of Sandy Lydon

By 1908, only portions of the rail on each end of the Ocean Shore line were running: Santa Cruz to Swanton, which is just north of Davenport, and San Francisco to Tunitas Creek, a few miles south of Half Moon Bay. The railroad never fully connected Santa Cruz to San Francisco. Ocean Shore stopped running trains by 1920 and never laid their second line. The Southern Pacific line was eventually sold to Union Pacific, which ran freight for the cement plant until the plant closed in 2010.

Why There Is a Tunnel

Creation of the railroad embankments meant completely blocking off the creeks and any associated estuaries and lagoons. Water flow was routed through tunnels made through the Santa Cruz Mudstone. The tunnels are on the north side of each beach and, despite large storms, have eroded little and have been adequate to handle the flow. In the picture below, the black arrow points to a tunnel where Liddell Creek comes out of the Santa Cruz Mudstone. You can follow the water to its exit at the ocean. The black rectangle shows the very linear railroad embankment that now defines the back of the beach.

An aerial view of Bonny Doon Beach. The black rectangle encompasses the embankment made by the filled railroad trestle. The arrow on the left points to the tunnel through which Liddell Creek drains to the sea. Photo: © Kenneth and Gabrielle Adelman, California Coastal Records Project, http://www.Californiacoastline.org

Liddell Creek draining through the man-made tunnel, which was drilled in 1907-1908 through the Santa Cruz Mudstone. Photo: Julia Gaudinski/Mobile Ranger

There’s Oil in Them Thar Hills!

In the farthest-right cove at Bonny Doon Beach (yes, the clothing-optional section), a tall skinny dike of sandstone cuts across the Santa Cruz Mudstone. A dike is essentially loose material. In this case, it’s the older and deeper Santa Margarita Sandstone, which was squirted up under pressure through the younger but harder mudstone. The dikes and the Santa Margarita Sandstone contain bituminous (asphalt-like) material in varying quantities. There are many similar dikes in the sea cliffs along the north coast of Santa Cruz. This one is unusual in how skinny and rectangular it is.

A sandstone dike that cuts across the Santa Cruz Mudstone. The blue line parallels the dike just above it. Photo: Julia Gaudinski/Mobile Ranger

Some of the bituminous sandstones just a few miles south, at Majors Creek, were quarried for paving material. Apparently, about 600,000 tons, valued at more than US $2 million, were quarried and sent by boat to pave San Francisco between 1888 and 1914. In the 1950s, the Husky Oil Company ran an experimental project to extract oil and gas by heating the sandstone in the drill hole and then recovering what melted. Over three years, they pulled out 3,000 barrels of oil and some gas. But costs were too high, overall, to make it economically viable.

Take the Self-Guided Mobile Tour

This piece is part of the North Coast Tour. Download the free app with many tours of the Santa Cruz area and beyond.

Sources Used

The Sandhills of Santa Cruz: There’s Shark Teeth Underneath

Ranger Salazar — Thu, 17 Sep 2015 13:30:22 +0000

Photo: Lauren Salazar/Mobile Ranger

Post Updated on June 22, 2016
Santa Cruz’s Sandhill habitat is highly sensitive so it is important to stay on designated paths when visiting them. The Sandhills in this post are not open to the public but these are:

Henry Cowell State Park: The Graham Hill Road entrance provides access to a Sandhill habitat overlook. A new Sandhills Mobile Visitor Center can be found near the campgrounds as well.

Quail Hollow Ranch County Park: Sunset Trail is nestled within Sandhill habitat and provides breathtaking views of the San Lorenzo Valley.

Bonny Doon Ecological Reserve: In 2008 this section of Bonny Doon was burned in a forest fire. A new trail here allows visitors to see the post-fire recovery of chaparral habitat within the Sandhills.

I grew up right near the Sandhills of the Santa Cruz Mountains and often heard stories of people discovering prehistoric sand dollars and sharks teeth. I searched for them myself but was never successful and so believed that maybe I was never meant to find one.

The story of the Santa Cruz Sandhills starts about 15 million years ago. In the Miocene Epoch, these currently hot and dry hills were submerged under a shallow but far reaching sea. Within it’s depths many marine species died and their remains fell to the ocean floor and were covered by layers of sediment.

Endemism In The Hills

During the formation of the Santa Cruz Mountains, this ancient seabed was pushed up and created the Sandhills of today. This uprising of ocean floor exposed prehistoric sand dollars, bones and sharks teeth. The sandy soils of the Sandhills have also created a very unique habitat where seven threatened and endangered species survive. Many are endemic, which means they are found nowhere else except in the unique Sandhills habitat of Santa Cruz County.

Male Mount Hermon junebeetle. Photo: Courtesy and © of Jodi McGraw

Sandhill soil drains quickly and contains much less organic material and nutrients in comparison to the surrounding lush redwood forests of the Santa Cruz Mountains. The white sand of the Sandhills reflects the sun’s heat making for sweltering temperatures in summer. Only adapted plant species that can handle high temperatures and lack of nutrients and water can survive the unforgiving elements of the Sandhills.

Sandhills look barren and contain primarily smaller stature shrubs and annuals compared to neighboring tree dominated redwood forests. For this reason it is fairly easy to recognize the change to Sandhills habitat. They are fairly easy to spot, scattered like little islands among areas of Bonny Doon and Scotts Valley. In fact, some of these different islands have endemic species found only within their specific Sandhill zone and not in all of the the Sandhills habitat.

Silverleaf Manzanita.
Photo: Courtesy and © of Jodi McGraw

The Zayante band-winged grasshopper makes its home in disturbed areas of the Zayante Sandhills, including trails, so watch your step. We all need to do our part to protect these plants and animals so they can persist for future generations.

Zayante band-winged grasshopper. Photo: Courtesy and © of Jodi McGraw

Today 4,000 acres of intact Sandhills remain in the Santa Cruz Mountains. 2,500 acres are undeveloped. Prior to development, mining operations and non-native species intrusion there were 6,000 to 7,000 acres of Sandhills habitat that were less fragmented. To learn more about the Sandhills and how to help protect them, read this article by the Land Trust of Santa Cruz County.

Map of the Santa Cruz Sandhills. Photo: Courtesy and © Jodi McGraw

Watch this short 5 minute video staring Jodi McGraw, the inspirational Sandhill expert and my personal Sandhill hero.

Discovering The Past

After graduating from UC Santa Cruz in 2015, I took on an internship to help restore the Sandhill habitat with Jodi McGraw Consulting in the Santa Cruz Mountains. On the last day of my two month long internship, a peculiar going away present laid on the sandy surface in my walking path. Right before taking a step I discovered a full shark’s tooth! I picked it up and held it close. This was the tooth I had always hoped to find. The hopes and dreams of my childhood magically came true!

Santa Cruz Mountain Sandhills. Photo: Lauren Salazar/Mobile Ranger

I eagerly emailed a few of my favorite local natural historians to share my curiosity of its origins. I was dying to know how old it was and to what species this tooth belonged to.

Frank Perry, fellow Mobile Ranger author, lime kiln expert and fossil guru, replied with a flood of information. Perry is also a Research Associate at the Santa Cruz Museum of Natural History and Curator of the Capitola Historical Museum. He has a wealth of knowledge in the field of Santa Cruz Mountains natural history. Here is some of his insight:

“That tooth is from a shark of the genus Isurus. It is the crown of the tooth, missing the root. It is probably an upper medial tooth, but I cannot say for sure without delving into the reference books.”

“The sand in the Sand Hills is from the Santa Margarita Formation, which was deposited when this area was under the sea some 10 to 12 million years ago.”

“…fossil teeth of about 20 different species of sharks and rays have been found in the deposit, as well as fossils of bony fishes, whales, dolphins, sea lions, sea cows, etc. Quarrying operations in the middle to late 1900s opened a remarkable window into the region’s geologic past.”

To learn more about what Frank Perry has to offer, check out his website and don’t miss his list of published works here.

Sources Used
- Personal communication with Jodi McGraw via email, owner of Jodi McGraw Consulting (JMc), Santa Cruz County, June 2016.
- Bay Nature
- Land Trust of Santa Cruz
- Zayante Sandhills Conservation Bank
- California Native Plant Society
- Sandhills-Background
- Perry, Frank: Personal Communication. July 9, 2015.
- Endangered Species Act
- Santa Cruz Sand Hills
- Biology of Plants
- CNPS Plant Communities of Santa Cruz

Bucking the Trend: Mount St. Helens Grows a Glacier

Ranger Pirela — Thu, 20 Aug 2015 13:30:19 +0000

Steam, gas and ash coming from the lava dome in Mount St. Helens in 1982. Photo courtesy USGS.

The eruption of Mount St. Helens forever holds a place in the memories of many people across the nation. On May 18, 1980, Washington’s great mountain received a geological face lift by blowing up all that stood in its way. The volcanic eruption and ensuing landslide took 57 lives, more than 200 homes, and destroyed almost 200 miles of highway road on that spring day.

The Volcano that Made a Glacier

Who would have thought that with the heat of continuing vulcanism that the crater could give birth to a glacier? But it did. Since the eruption, the world’s youngest glacier has been growing in the crater of the active volcano. After the blast in 1980, a thick collection of loosely arranged rocks gathered on the floor of the crater and protected the accumulating snow from both the heat of the lava dome and the melting rays of the sun. Heavy snows, avalanches, and rock falls, allowed the glacier to grow. It gained about 50 feet a year in thickness and 135 feet per year in length, until 2004.

The crater floor in October, 1980, after the eruption but before Crater Glacier was born. Photo courtesy USGS.

Crater Glacier in October, 2000, prior to the 2004-2008 eruptive cycle. Photo courtesy USGS.

From 2004 to 2008, Mt. St. Helens groaned and steamed again with volcanic activity. A new lava dome formed and the glacier lobes were squeezed and compressed between the caldera wall and the new dome. This caused the ice to move more rapidly downhill and was almost split into two separate glaciers. The volcanic activity melted about 10% of the glacier’s mass and changed it from a smooth crevasse-free glacier to a chaotic jumble of ice falls with many crevasses. The cold rock at the edge of the glacier insulated it from flowing lava and prevented the glacier from melting completely, and possibly causing catastrophic mud flows.

Crater Glacier February 2005. It is nearly split at its south end by the new lava domes. Photo courtesy USGS.

Crater Glacier in October 2006. Photo courtesy USGS.

The Little Glacier that Could

Crater Glacier, officially named the the Tulutson Glacier in 2006 (from the local native Cowlitz language word for ice), is currently over one mile long and 650 feet thick. In the mid-2010s, it is getting about 15 feet thicker and 330 feet longer every year. This glacier, nestled in a warm volcano, is also fighting against a larger climate warming trend as it continues to grow. While there are isolated instances of glacial growth across the globe, most ice sheets and glaciers are melting. The paradoxical success story of Crater Glacier and Mt. St. Helens is particularly spectacular.

Crater Glacier in 2011. Photo by J. Brew

Sources Used
- How the World's Newest Glacier is Forming on Washington's Mount St. Helens...Anna Konstantinides. Daily Mail website.
- Crater Glacier. Wikipedia website.
- Glaciation at Mount St. Helens. USGS.gov website.
- Signs of Earth: The Big Thaw. Daniel Glick. National Geographic website.
- Are Glaciers Growing or Retreating?. Indians of All Nations. Skeptical Science.com website.
- Why Are Glaciers Melting?. Kevin Mathias Buzzle.com website.

California: Beauty of Tectonic Proportions

Ranger Gaudinski — Mon, 03 Aug 2015 13:30:22 +0000

Big Sur Coastline. Photo by David Iliff.

Plate Tectonics

California’s landscape is shaped in large part by plate tectonics, and in particular, the movement of the North American, Pacific, and Farallon plates over the past 150 million years. The existence of our coastal mountains, large central valley, and Sierra Nevada Mountains (to focus on the state’s main features) are due primarily to the movements of these three plates. You have probably heard of the North American Plate (almost all of North America), and the Pacific Plate (most of the Pacific Ocean). But you may not have heard of the Farallon Plate, which was a different large plate in between the Pacific and the North American Plates from about 150 to 25 million years ago.

The major mountain ranges in California. The Central Valley is the brown elongated feature in the center of most of the state. Image courtesy USGS.

In the oldest (bottom) image you can see a lot of the Farralon Plate (green). By the top image, all of the Farralon Plate along California has been subducted under the North American Plate. This left the North American and Pacific plates in direct contact and gave rise to the San Andreas Fault system. The green piece of the Farralon plate that is left is the Oregon and Washington coast – where there is still currently subduction – and the Cascade Volcanic Chain! Image courtesy USGS.

The Farallon Plate was subducted under (went underneath) the North American Plate. As it was subducted, the accumulated sediments on the top of the Farallon Plate were scraped onto the North American Plate, creating much of the present day coastal mountain ranges.

The Sierra is Born

As the subducting Farallon Plate plunged deep beneath the North American Plate, it melted and created an inland volcanic chain. By about 60-70 million years ago the deep centers of these volcanoes had cooled and were beginning to be uplifted; they formed the present day granites of the Sierra Nevada.

A long with the volcanic chain you get a basin in front of them and this basin filled with sediment and became California’s Central Valley.

Schematic of a subduction zone similar to the one that created California’s geography. The trench became the Central Valley. The magma core of the volcanic arc became the Sierra Nevada mountain chain. Photo courtesy

Sierran Granite. This was once magma deep inside a volcanic chain much like today’s Cascade Volcanic Chain in Washington and Oregon. Photo by Justin Johnson.

Creation of the San Andreas Fault

By about 25-30 million years ago the Farallon Plate and the spreading center that created it were entirely subducted. This left the Pacific Plate in contact with the North American Plate. Subduction stopped and the San Andreas Fault was born. The movement between this new contact was mostly side-to-side with the Pacific Plate heading northwest and the North American Plate heading southeast. Technically it is called a right-lateral strike-slip fault.

The main trace of the San Andreas Fault in California. Image courtesy USGS.

The San Andreas Fault is part of a complex system of several faults. Its motion is not just side-to-side (at an average 2 inches per year) but also involves steady uplift of the North American Plate relative to the Pacific Plate.

In Santa Cruz, my home turf, we are on what is called the Salinian Block, a chunk of granite brought northward, and also upward, by the San Gregorio and San Andreas faults. Much of this transport happened during the Miocene while the present day Salinian Block was at the bottom of the ocean accumulating sediments. Some of these sediments became the Santa Cruz Mudstone and the Purisima Formation.

Classic shore platforms and pocket beaches of the Santa Cruz Mudstone; Long Marne Lab.

Sources Used
- Farallon Plate:This Dynamic Earth. USGS Website. http://pubs.usgs.gov/gip/dynamic/Farallon.html.
- The Geology from Santa Cruz to Point Año Nuevo—The San Gregorio Fault Zone and Pleistocene marine terraces. By Gerald Webber and Alan Allwardt. In: Stoffer PW, Gordon LC, eds. Geology and natural history of the San Francisco Bay Area: a field-trip guidebook: 2001 Fall Field Conference, National Association of Geology Teachers, Far Western Section: September 14-16. USGS Bulletin 2188; 2001:194.
- Natural Bridges Field Trip Guide. Christie Rowe. University of California Earth Sciences Webpage. http://www.es.ucsc.edu/~crowe/structure/natbridges.html.
- Paleosurf: The Ancient Beaches of Santa Cruz. Christie Rowe, Catherine Riihimaki. Hellatite Gallery Website. http://es.ucsc.edu/~geoclub/paleosurfpics.html.
- The San Andreas Fault. United States Geological Survey Website. http://pubs.usgs.gov/gip/earthq3/safaultgip.html.
- A Coast to Explore: Coastal Geology and Ecology of Central California. Miles O. Hayes. Pandion Books; 2010.

Racetrack Playa: Turtles Race Faster Than These Famed Stones!

Ranger Pirela — Thu, 16 Jul 2015 01:10:44 +0000

A distant view of Racetrack Playa. Photo by Daniel Mayer. Wikipedia.

From a far glance, the flat, dry surface of Racetrack Playa, in Death Valley, California, invites you to perceive a cloudy lake. Nearing the Playa, this mirage evolves into a reality of silt and clay where nothing seems possible. Here, the lake bed serves as a respite to the surrounding mountains as it waits eagerly for the meager annual rainfall of 3 inches. With the help of this water, the surface changes from dry silt to wet mud, offering us an incredible mystery from a muddy mess.

The sailing stones in motion at Racetrack Playa. Photo by Daniel Mayer Wikipedia.

These rocks and their trails are sprinkled throughout Racetrack Playa, proving seemingly impossible movement. Wakes of thirsty ground, frozen in time, linger behind them, showcasing their lively sailing trips across the dry lake bed underneath.

A rock with a GPS unit inside a cavity bored into its top. Photo from Norris R, Norris J, Lorenz R, Ray J, Jackson B (2014).

Explaining the Sailing Stones

Scientists have struggled to explain the movement of these stones for decades. Until recently, there were only two main theories explaining the movement: hurricane force winds, or thick ice. Both theories accounted for wind, rain and ice but required these conditions to create a Samsonite feat of natural strength to move the rocks. Thanks to new technology, scientists have finally been able to get some answers.

Slow and Steady

In 2011, a team from Scripps Institution of Oceanography set a weather station in the Playa and placed GPS tracking devices on the stones. They expected it to take years to get the right coincidence of unknown factors, but as luck would have it, just two years later they saw – and measured – the rocks moving!

Following a cold December night, the team traveled to the site. A thin, frozen pond had trapped the stones overnight due to an unusually high amount of snow. A light breeze was noticed in the mid-morning but didn’t affect the stones until the bright sun quickly began to melt the ice in the early afternoon. The melting ice began to crack and pop, forming wide and light sheets of ice. The ice, due to the force of the wind, applied buoyancy to the trapped rocks and bulldozed the rocks across the surface. This “ice sailing” process slowly moved the rocks and created the mysterious trails.

These stones, surrounded by ice continue their journeys. Photo courtesy Ralph Lorenz. RacetrackPlaya.org.

Recordings from the December site visit. Images courtesy Ralph Lorenz. RacetrackPlaya.org.

As for racing on the playa, these stones are not breaking any speed barriers. Recordings showed winds at maximum speeds of only 10 mph, and ice less than ¼ of an inch thick. These conditions, combined with ice melt from a bright sun, were able to move rocks ranging from 18 to 37 pounds about 6 to 20 feet per minute (0.07 – 0.23 mph). To put this in perspective, the average turtle, who travels at a speed of 264 feet per minute (3 mph), is almost 13 times faster than the sliding stones! Even more so, the rare factors and slow speed of the process have only moved the rocks for a total of a few minutes in the past decade!

Sources Used
- Mystery Solved: “Sailing Stones” of Death Valley Seen in Action for the First Time. Scripps Institution of Oceanography website.
- ‘Wandering Stones’ of Death Valley Explained. Alexandra Witze. Nature.com website.
- The Sliding Rocks of Racetrack Playa. Hobart King. Geology.com website.
- Trail Formation by ice-shoved “sailing stones” observed at Racetrack Playa, Death Valley National Park. Ralph D. Lorenz, et. al. Racetrackplaya.org website.
- Racetrack Playa.Wikipedia.

Historic Lime Kilns of UCSC

Friends of Cowell Lime Works Historic District — Mon, 29 Jun 2015 13:30:17 +0000

Each pot kiln had four doorways at the base. Originally, each doorway was fitted with a heavy iron door to control draft. Photo courtesy of the Friends of the Cowell Lime Works Historic District.

Near the main entrance to the University of California, Santa Cruz lies the Cowell Lime Works Historic District.

Lime was an essential building material in late 19th century California, and Santa Cruz was at that time one of the state’s most important lime-producing regions. Limerock was fired in giant kilns to convert it into lime, which was a key ingredient in mortar, plaster, whitewash, and many other industrial products.

Santa Cruz lime had a reputation for being of fine quality. It helped build San Francisco in the decades after the Gold Rush. It was also shipped to other cities up and down the California coast, inland to Sacramento and the San Joaquin Valley, north to Oregon, and even to Hawaii.

Advertisement for Davis & Cowell, 1867. Photo courtesy of the Friends of the Cowell Lime Works Historic District.

Cowell Lime Works

The Cowell Lime Works Historic District preserves the most intact 19th century lime manufacturing facility in California.

A succession of companies operated here. The first to make lime on a large scale was the firm of Isaac E. Davis and Albion P. Jordan starting in 1853. In 1865 Henry Cowell bought A. P. Jordan’s half of the business and, in 1889, Davis’s share. Cowell, and later his sons, ran lime-making operations at this and three other nearby locations in Santa Cruz County. They also made lime in the Sierra foothills and in Washington state. The last of Cowell’s Santa Cruz County kilns, beside Highway 9 in what is now Henry Cowell Redwoods State Park, ceased operation in 1946.

Lime Kilns (Pot Kilns)

These giant stone kilns were the heart of the lime-manufacturing operation. The three kilns on the left are pot kilns (aka batch kilns or intermittent kilns). The interior of each measures about 11 x 33 x 15 feet high. The front walls are about 6 feet thick, and each kiln has four doorways at the bottom. The kiln on the far right is a continuous kiln (see separate stop).

The kilns are lined with fire-bricks, which have partly melted from the intense heat. Company names stamped on the bricks indicate that they were imported from northern England. Photo courtesy of the Friends of the Cowell Lime Works Historic District.

Chunks of limerock were loaded into the top of each pot kiln, and the lumps of finished lime were removed through the doorways at the bottom. It took the workers approximately 2 days to load a kiln, 5 days to fire, 2 days to cool, and 2 days to unload.

The limerock had to be held at around 1,800˚F to convert it to lime. The workers had no instruments in those days to exactly measure the temperature. They had to judge by the color of the fire and the look of the rock to know when it was done. This took years of experience. If the rock was cooked too much, it turned into “dead-burnt” lime and was useless (would not mix with water). If it was not cooked enough, a core of unconverted limerock would remain hidden in the center, and customers would gripe that they were cheated.

For those of you who want to know the chemistry, the rock is made of calcium carbonate, CaCO3. The heat drives carbon dioxide, CO2, gas out of the rock, leaving calcium oxide, CaO, which is the lime.

Each kiln produced over 1,000 barrels of lime per burn. The pot kilns were incredibly inefficient, and consumed between 75 and 150 cords of split redwood as fuel for each load.

By having three kilns, each at a different stage of production, the plant could produce a near continuous supply of lime. These kilns were remodeled in the 1890s and were in operation until around 1920.

Take the Self-Guided Mobile Tour

This piece is part of UCSC Lime Kilns Tour by Frank Perry on behalf of The Friends of the Cowell Lime Works Historic District. Download the free app with many tours of the Santa Cruz area and beyond.

The content for the AppTour was prepared by The Friends of the Cowell Lime Works Historic District, University of California, Santa Cruz, and is © 2015 by The Friends. Much of the information is from the book, Lime Kiln Legacies: The History of the Lime Industry in Santa Cruz County. The book can be purchased at the Museum of Art and History in person or on-line. It’s also available through Amazon.com.

During this tour you will see that some of the historic buildings have been put to modern uses by the University. Others remain unused but are gradually being restored with private gifts of funding and materials. For more information on how to help, contact the Friends of the Cowell Lime Works Historic District. This UCSC friends group is dedicated to researching, preserving, and teaching about the history of this historic site.

Sources Used

Below the Buildings: Karst and Construction at UCSC

Ranger Salazar — Thu, 14 May 2015 05:24:19 +0000

Sinkhole near East Remote Parking Lot. Photo courtesy of UCSC Environmental Studies Department.

Imagine a building site with a multimillion dollar project in full swing and suddenly the concrete for its foundation starts to disappear into a dark sinkhole with depths unknown. Sound like a rare occurrence? Not entirely. While this an extreme, though true case, sinkholes have wreaked havoc in greater or lesser degrees on seven buildings on the University of California Santa Cruz (UCSC) campus.

Sinkhole-filled topography underlies the UCSC campus. It is called “karst topography” and is created when limestone/or marble bedrock dissolves for many thousands of years and leaves deep holes, winding tunnels and narrow fractures. The reaction between acidic groundwater and the underground lime causes the rock to dissolve into the ground water and simply flow away. A swiss cheese pattern is created underground with holes ranging from tiny to huge and cavernous. This geologic phenomenon has allowed many-a-student to have fun in the caves but also proves quite challenging when it comes to constructing large buildings.

I recently had the opportunity to speak with Dr. Gerald (Jerry) Weber about the karst geology of the UCSC campus. He has served as a local planning advisor, taught the UCSC summer geology field camp for 20 years, and has been investigating geologic problems in California for about 50 years. Jerry’s services are used when sinkholes threaten building projects on campus and he has some great stories to tell.

Sink Hole Spotting

The UCSC campus is peppered with sinkholes only noticed by the trained eye. The 50 plus sinkholes on campus are the most noticeable characteristics of the underlying karst topography. When caves grow so large that the weight of the ceiling material is no longer supported, it collapses; thereby creating a sinkhole (doline). Other ways that sinkholes are created are from a settling of surface material over highly fractured dissolving marble or the sinking of soil that has filled widened cracks in marble below.

Map of sinkholes and fracture/fault zones on campus. Photo courtesy of the UCSC Environmental Studies Department.

The sinkholes leave the imagination to wonder to what depths these caves reach. Geologists conducted a 200 foot core sample and still haven’t a clue of the extent of the karst cavities. At first, the UCSC campus terrain seems solid and continuous. Images of rolling grassy hills and massive redwoods disguise the deep voids that could be just 15 to 30 feet below the soil surface.

In front of the Baskin Engineering building, hidden beneath the shade of redwoods, lies a large sinkhole. Photo courtesy of Lauren McEvoy.

It’s San Andreas’ Fault

Most people know of the San Andreas Fault that runs almost the length of California but not many are aware of the 33 plus fracture zones and faults that are spread across the UCSC campus. Disguised as dry creek beds, Chancellor Gulch and Jordan Gulch are the largest fracture/fault zones on campus running nearly the entire length of the campus. Movement along these faults creates areas that are pulverized and more permeable. These porous areas make the perfect outlet for groundwater flow in the rainy season and create underground rivers with no destination in sight. Most of the creeks on campus will appear from springs up river and then disappear underground into a closed sinkhole (swallow hole) into the deep unknown.

Karst topography at its full extent. Photo from the collection of Jerry Weber.

Where does the Water Go?

No one really knows where all the water goes. Geologists in 1989 drilled wells into the fault/fracture zones to test the amount of stored water. They have found huge water rich aquifers within the karst producing up to 200-300 gallons per minute with little drop in the water table. Despite the sheer amount of water stored right under campus, the city supplies the campus with water for reasons that mystify me in my investigations. Water in karst systems has a high potential for containing contaminants due to lack of filtering (percolating) before reaching an aquifer. Most drinkable water from aquifers has been filled with water that has filtered through layers of clay and other cleansing particles. Instead, the water in karst systems go from cloud, to ground, to storage system much more quickly and with less natural filtration.

Building on Karst

Avoiding underground caverns is challenging when planning for development. Before building on campus is approved, extensive geologic and geotechnical engineering studies are done to gauge the strength of the underlying bedrock. Exploratory drilling to sample the bedrock for voids is done for every major building project on campus. Voids were found before and during construction of eight known structures at UCSC and the weight of a few of these buildings proved too much for the underlying karst.

Prior to the construction of the Science and Engineering Library a large narrow void filled with a toothpaste consistency clay material was discovered at the exact location of the planned library. Construction began after coming to realization that the only way of building over such terrain was to construct an underground bridge spanning the river of clay. Hundreds of students use the library daily without a clue that a river of mud lies just below the foundation of the building.

Thirty boreholes were done to understand the geology under the Science and Engineering library prior to construction. Photo courtesy of Lauren McEvoy.

There is a very large sinkhole in front of the Baskin Engineering building that gives a clue as to what lies beneath the adjacent building. Baskin Engineering was constructed atop a very deep cavern with unknown depths. When construction began the void was discovered and filled with an enormous amount of cement day after day until workers realized that the hole was not being filled at all. Their efforts to fill the hole failed. Instead, cement pillars 300 feet in length were placed deep into the earth in stable bedrock surrounding the void. Its as if Baskin is hanging over the mouth of a hungry giant.

Baskin Engineering straddles a big karst cavern. Photo courtesy of Lauren McEvoy

After the construction of the Earth and Marine Building foundation, the weight of the cement foundation proved too much for the hole-filled karst below. In December 1991, just weeks after completion of the foundation, an enormous rain storm whipped through the campus over the New Years Holiday. Construction workers came back from their holiday to discover that their hard work had fallen victim to the inevitability of the karst topography and rainwater combination.

The foundation had given way and collapsed into an underlying cavern. Geologist, Jerry Weber, stuck a 30 foot rebar into one of the open holes and couldn’t feel the bottom of the cavern. Construction workers pumped cement into the exposed holes until the foundation was stable enough to prevent the cavern from eating any more of the building.

Earth and Marine Sciences Building. If its not tree sitters, its sinkholes that are trying to stop development on campus. Photo courtesy of Lauren McEvoy

Geek Details: Chemistry of the Karst

Rainwater lands on the campus soil where it flows and accumulates tiny dissolved acids and carbon dioxide gas. Groundwater becomes slightly acidic when the carbon dioxide dissolves, producing carbonic acid.

carbon dioxide (CO2) + water (H2O) = carbonic acid (H2CO3)

When the acidic groundwater finally reaches the marble bedrock (cooked limestone), it finds its way into tiny cracks, joints and fault lines. As carbonic acid laced rainwater drizzles through these cracks, the lime within the marble dissolves. 97% of marble on campus is composed of lime which means that the lime loving carbonic acid has potential to drastically change the structure of underground topography by dissolving a large percentage of the marble.

lime (CaCO3) + carbonic acid (H2CO3) = calcium ion (Ca++) + bicarbonate ion (2HCO-3)

Sinkholes can be formed many ways. Photo courtesy of the UCSC Environmental Studies Department.

Over time, these tiny permeable cracks enlarge and create tunnels and caves large enough to throw a party in. Despite the severe effect that acidic water has on lime, it is not a risk to humans. It only affects the geology so greatly because it has been working at dissolving lime for the past several hundreds of thousands of years (on a geologic timescale).

Take the Self-Guided Mobile Tour

This piece is part of the UCSC Natural History Tour. Download the free app with many tours of the Santa Cruz area and beyond.

Sources Used
- University of Santa Cruz Museum of Natural History Collections website.
  http://mnhc.ucsc.edu/
- UC Santa Cruz Natural Reserves Website http://ucsantacruz.ucnrs.org/reserves/ucsc-campus/1881-2/habitats-and-features/caves/
- The Natural History of The UC Santa Cruz Campus Book. Second Edition. Haff et al. Environmental Studies Department, University of California, Santa Cruz. 2008
- Personal Communication with Dr. Gerald (Jerry) Weber, Lecturer Emeritus University of California Santa Cruz, Geologic Consultant. April 2015.

The Rocks of Santa Cruz’s Central Coast: The Purisima Formation

Ranger Gaudinski — Thu, 19 Mar 2015 13:39:33 +0000

An example of the Purisima Formation at Mitchell Cove along West Cliff Drive. The top part of the cliffs where most of the ice plant is growing are composed of much younger Quaternary deposits. The bottom section is the Purisima Formation. The contact between them can be seen clearly in the middle of the photo.

The Purisima Formation is the rock type that shapes the landscape characteristics of the central and southern Santa Cruz coast. It is present from the intersection of Swift Street and West Cliff Drive all the way down the coast to Seacliff Beach in Aptos. Relative to the Santa Cruz Mudstone it is not very resistant to erosion. In fact, the change of rock type from the more resistant Santa Cruz Mudstone to the less resistant Purisima Formation near Lighthouse Point, allowed the landward erosion that caused the Monterey Bay to form where it did.

Creation of the Purisima

This formation consists of inter-layered yellow-gray siltstones and blue-gray sandstones and gets its name from Purisima Creek in San Mateo County. It was created during the Pliocene and the last gasp of the Miocene about 3-7 million years ago. The deposits were laid down in a shallow sea that was gradually shrinking. If you were to walk from West Cliff Drive and Merced Avenue all the way to Seacliff Beach, you would be getting younger in geologic time.

Over this 4 million year period of deposition, the rocks record a shift from deeper off-shore conditions (primarily yellow-gray silts with a lot of silica-rich organisms, known as diatoms, deposited in fairly quiet water) to shallower near-shore conditions (primarily blue-gray sandstone deposited from rivers dumping into estuaries and bays). There are a few mollusk fossils and whalebones in the cliffs of the Purisima Formation near West Cliff Drive but you will find the best exposures of them along the cliffs below Depot Hill in Capitola.

Capitola Overlook from Depot Hill, May 2011. Image adapted from photo by fogcat5 via Flickr.

Depot Hill Bluffs in Capitola, June 2012. Image adapted from photo by fogcat5 via Flickr.

The Purisima and Lighthouse Point

Lighthouse Point is composed of a particularly resistant part of the Purisima Formation. In general the Purisima erodes fairly easily. However, Lighthouse Point, and a few other resistant headlands like San Lorenzo Point and Pleasure Point, have withstood the ocean’s erosive powers. Lighthouse Point, in fact, protects Monterey Bay’s northern beaches from much of the wave energy they would otherwise get from the dominantly northwest waves. Even so, the Purisima at Lighthouse Point does erode. In fact it tends to form caves …

Modern day Lighthouse Point showing the Purisima Formation and the Mark Abbott Memorial Lighthouse which was built in 1967.

Under cutting of Lighthouse Point by caves continues. This picture was taken on the westside of the point in 2014.

Caves Endanger Original Lighthouse

The original location of the Santa Cruz Lighthouse, built in 1869, was close to the cliffs. In 1878, less than ten years after it was built, a letter was sent to the Lighthouse Board noting that three large caves (all over 50 feet long and 50 feet wide) penetrated the point, and the largest extended to within 12 feet of the lighthouse.

To preemptively save the lighthouse from potential catastrophic cliff erosion, the Lighthouse Board ordered it to be picked up and moved 300 feet landward. Thus from 1879 to 1948 the lighthouse was located on the north side of what is now West Cliff Drive.

Aerial view of Lighthouse point circa 1941. Image is used courtesy of Frank Perry. Ed Webber was the photographer.

While the caves did not collapse catastrophically, they did erode about a foot per year and eventually created the cove that exists today in front of the modern day lighthouse. Check out our piece on Lighthouse Point for a more complete history and the interesting story of the lighthouses that lit the way for ships before the one that stands today.

Take the Self-Guided Mobile Tour

This piece is part of the West Cliff Drive Tour. Download the free app with many tours of the Santa Cruz area and beyond.

Sources Used
- Lighthouse Point: Illuminating Santa Cruz. Frank A. Perry. Santa Cruz, California: Otter B Books; 2002.
- Living With the Changing California Coast. Gary B. Griggs, Kiki Patsch, Lauret E. Savoy. University of California Press; 2005.
- Personal Communication with Frank Perry, Historian, Santa Cruz County, February 2012.
- Personal Communication with Gary Griggs, Distinguished Professor of Marine Sciences, University of California Santa Cruz, February 2012.
- Solid beam shines from lighthouse once again. Shanna McCord. Santa Cruz Sentinel. December 19, 2013.

The Huge Boulders Along the Santa Cruz Shoreline: A Common Coastal Story

Ranger Gaudinski — Mon, 19 Jan 2015 02:39:40 +0000

A view from the mountains to the eroding coast along West Cliff Drive in 2010. Picture © Kenneth and Gabrielle Adelman,
California Coastal Records Project www.Californiacoastline.org.

If you live along or visit the west coast of California you have likely seen various types of structures designed to stop the coastline from eroding. Two common ways to decrease erosion are to place rip-rap (1– to 2–ton boulders boulders) along the cliff edges and to construct concrete sea walls. In recent decades, these methods of protecting or “armoring” the coast are so pervasive that people might not even notice them. I live near West Cliff Drive in Santa Cruz, California, and I am often amazed that people strolling along this beautiful section of the coast don’t even realize that rip-rap is not a natural feature.

The Cliff House along West Cliff Drive, Santa Cruz, California on a 1950s era postcard. Image courtesy of Frank Perry.

The Cliff House in 2012 from the same vantage point as the postcard. Rip-rap now fills both beach coves.

Development and Storms

Much of the development along the California Coast, including Santa Cruz, took place between the mid-1940s and the mid-1970s—a three decades-long period of below-average rainfall and storm frequency. In the late 1970s the stable weather period began to change with large storms in 1977–78 and 1982–83. These storms led to increased studies of trends in ocean and atmospheric circulation.

ENSO Cycles

These studies found that changes in atmospheric pressure, wind patterns, and ocean circulation in the equatorial Pacific create cycles known as the El Niño/La Niña Southern Oscillation (ENSO). El Niño conditions create more severe weather with above average rainfall and more frequent coastal storms. In contrast, La Niña conditions create mild weather with below normal rainfall and storm frequency. Seventy five percent of the storms that have been particularly damaging between 1910 and 1995 occurred during El Niño events.

The El Niño of 1982–83

The El Niño storms of 1982–83 did more damage than any winter since. That winter, eight major storms hit the California coast and were particularly damaging for several reasons. First, sea levels were already elevated by the warmer El Niño conditions; second, many of the storms hit at the peak in spring high tides (thus they scoured away more sand and reached higher and further onshore); and third, the swells came not from the northwest as is typical but from the west (where the waves struck the coast dead on with no energy loss from refraction) and southwest (directing energy to areas that are typically more sheltered). Thirty three ocean-front homes were destroyed and over 3,000 homes and businesses were damaged.

The Armoring of West Cliff

The first rip-rap on West Cliff Drive was installed in the mid-1960s. However, most of the armoring there today was installed in the 1980s and early 1990s, which was a period with several strong El Niño events.

Armoring also impacts coastal ecology by covering beach habitat used by birds and fish, algae, and invertebrates. For example, birds need protected rocks along the coast to roost and breed. Because armoring prevents the formation of new peninsulas, arches, and sea stacks in favor of a smooth armored coast, this habitat will get even more scarce.

This cliff is part of the peninsula that forms Lighthouse Point. It provides great resting places for these Brandt’s cormorants.

The Coastal Commission

The California Coastal Commission was created by the voters of California in 1976 and regulates development along the coast. Under their regulations new armor is only allowed to protect existing structures that are threatened. New development must be set back far enough to avoid being threatened by erosion for its projected lifespan. However, these regulations are sometimes evaded due to ambiguous language and politics.

Adding sand to beaches, which can increase beach width and decrease erosion has been tried and considered as a long-term mitigation strategy. But the financial costs are huge and the effectiveness variable and often only short-term, especially in California where sand moves southward along the coast at high rates (a process known as littoral drift).

The Future of the Coast

Eighty six percent of California’s coast is eroding. A rising sea level and more severe and perhaps more frequent storms from human-induced climate change will only exacerbate coastal erosion. From the perspective of a homeowner on West Cliff Drive, or on any part of the California Coast, protection from wave erosion is important. However, it comes at a high cost. Millions of dollars of federal, state, and private money are spent every year on coastal armoring.

A sea wall and rip-rap along West Cliff Drive, Santa Cruz, California, 2011.

What do you think about the varying trade-offs to homeowners, the public, animals, and the environment? Should new development along the coast be allowed? Should existing structures be allowed to protect themselves indefinitely—and at whose cost? In some cases structures have been torn down or moved. The coastline is retreating landward, and this trend will continue and probably accelerate.

Rip-rap filling the beach between San Jose and Stockton Avenues along West Cliff Drive, Santa Cruz, California. Photo: Archer Koch of MultiRotorCam.

Take the Self-Guided Mobile Tour

This piece is part of the West Cliff Drive Tour. Download the free app with many tours of the Santa Cruz area and beyond.

Sources
- El Niño Southern Oscillation: Cold and Warm Episodes by Season. US National Weather Service Climate Prediction Center. National Oceanic and Atmospheric Administration Website.
- "The Impacts of Coastal Protection Structures in California’s Monterey Bay National Marine Sanctuary," by Rebecca Stamski. Marine Sanctuaries Conservation Series, MSD-05-3, 2005. US Department of Commerce, National Oceanic and Atmospheric Administration, Marine
  Sanctuaries Division.
- Living with the Changing California Coast, by Gary B. Griggs, Kiki Patsch, and Lauret E. Savoy. University of California Press, 2005.

Lake Arrowhead: Holiness, Healing, and Hotels

Ranger Gaudinski — Fri, 16 Jan 2015 15:52:47 +0000

The arrow above Lake Arrowhead. Photo by Michael C

Lake Arrowhead gets its name from the huge arrow shape emblazoned on the face of one of the mountains in the San Bernadinos in Southern California. As a child, I had always thought it was shaped by people, but it turns out the 1,375 ft tall and 449 ft wide arrowhead is natural. The shape on the mountainside exists from a bizarre mix of bare rock ledges and vegetation contrasts. The arrow shape is made of exposed quartz, gray granite, and light green wild sage. It is surrounded by darker vegetation (greasewood and chaparral) which is why the arrowhead is visible.

Holiness

Many legends exist as to how the arrowhead came to be, but the most popular story told is from the Cahuilla Indians. The God of Peace, also known as the Great Spirit, shot a fiery arrow across the sky to guide the Indians to their new homeland. During their trek, the Indians saw the arrow soar through the sky and embed its head into the side of a mountain. The tip of the arrowhead pointed down to a natural hot springs below, pointing the way to their new home. They considered the hot springs to be holy ground because they believed it had healing powers.

In 1851 Brigham Young, founder of Salt Lake City and early leader of the Latter Day Saints (or Mormons), had a vision of an arrowhead on the side of a mountain pointing to a valley down below. He then sent two followers to find the location and start a new branch of Zion. The Mormons found the hot springs underneath the arrowhead and ultimately built many of the original roads in the area.

Healing Waters

After the Mormons left the springs, David Noble Smith opened up Smith’s Hygienic Sanatorium to treat sick people with the hot, medicinal mineral water. Smith enlarged his sanatorium into a hotel as word spread quickly about the nearby healing waters. People were also drawn to the hotel because of the crystal clear waters from the area’s streams. The spring water’s popularity prompted Seth Marshall to bottle it in the hotel’s basement. This was the beginning of what is known today as the Arrowhead Water Company.

Serious Hotels

Healing those with consumption, dropsy, and other incurable diseases was not financially lucrative. In 1883 Smith was forced to lease his sanatorium to Messrs. Darby and Lyman of Los Angeles who renamed it “Arrowhead Springs Resort.” They were unhappy with the small hotel but could not do what they wanted as Smith held title. Smith died in 1885. Darby and Lyman secured title and within three days the property burned down.

Panorama of Arrowhead Hot Springs, San Bernardino, August 1907. Photo: Courtesy of
Pilsbury Picture Company

Three additional hotels occupied the area, one built by Darby and Lyman in 1886. Perhaps ironically, it burned down in 1895. A third, built in 1905, was bought by a Hollywood Consortium in 1930 and became a hangout for the rich and famous. It burned in 1938 from a forest fire. The last and still standing Arrow Springs Hotel was built in 1939 as a luxurious affair designed to lure back the Hollywood set. It didn’t really work. It was taken over in 1944 to become a naval hospital. Over 6,000 Navy battle casualties received treatment there between 1944-1946. After that it lost its luster as rich people now had the option to fly to vacation spots in Mexico and Hawaii.

Hot Springs Hotel at Lake Arrowhead, 1915. Photo: Courtesy of Pierce, C.C. and from the California Historical Society Collection, 1860-1960

In 1962 Arrowhead Springs was reborn as the international headquarters of the Campus Crusade for Christ. In 1991 they moved their headquarters to Florida but continued to hold conferences there until 1999. There are rumors of grandiose plans, but the area is currently closed to the public.

Updated August 9, 2016

Sources Used
- Arrowhead Hot Springs and its Hotels. By Nicholas R. Cataldo.City of San Bernadino Website.
- Arrowhead. Arrowheadspringwater.blogspot.com website.
- Guidebook of the Western United States Part C: The Santa Fe Route. N.H. Darton and Others. 1915 Bulletin - United States Geological Survey, Issues 613-614
- Arrowhead Watersource Information. Arrowhead Direct Website.

Beach Bowling: Paleo Style

Ranger Lautamo — Mon, 12 Jan 2015 05:33:32 +0000

Bowling Ball Beach. Photo courtesy of John ‘K’. (December 2012)

Aptly named Bowling Ball Beach (part of Schooner Gulch State Beach), the geologic wonders here are plenty and plenty strange. Low tide reveals spherical rocks, two to three feet in diameter, resting in rows within naturally occurring ‘lanes’ within the surf. And if the giant paleo-bowling alley were not enough, just to the north, massive english muffins decorate the sandstone cliffs and wet sand.

The rocks on this remote Northern California beach in Mendocino County are sandstones and mudstones that were deposited on the sea floor during the Miocene (5-25 million years ago).

Image courtesy of Ted from geologictrips.com.

So just how do these massive bowling balls form?

These round rocks are unusually large concretions. Concretions form when minerals like silica or calcite concentrate around a common center and cement the grains of sand, silt or clay into hardened spheres. The concretions grow larger and larger over millions of years and can withstand weathering better than the surrounding material within the rock formation. Thus as the surrounding rock is eroded away by wind and waves, the concretions remain. Those in the cliff faces fall to the beach, those on the beach surface, largely stay put.

Bowling Balls in neat rows on the beach. Photo courtesy of Chris de Rham. (June 2008)

A bowling ball protrudes from the upturned sandstone bed.
Photo courtesy of Ted from geologictrips.com.

A concretion on the beach is still surrounded by sandstone from the host rock formation.
Photo courtesy of Ted from geologictrips.com.

It’s Not a Dinosaur Egg, It’s a Concretion!

Concretions have been mistaken for dinosaur eggs before, most famously in Chechnya in 2012. Dinosaur eggs are much smaller, however and too fragile for so many to remain intact like the rocks at Bowling Ball Beach. Another way you can tell the bowling balls are not dinosaur eggs is that wave patterns in the sand that formed as the sand was originally deposited can be followed from within the “host” sandstone into the round concretions (see photo above).

Rock concretions have been mistaken for fossilized dinosaur eggs like these ones from the fossil exhibit in the Kunming Natural History Museum of Zoology in Yunnan, China. Photo courtesy of Daderot. (August 2011)

From Horizontal to Vertical: Formation of the Lanes

What makes this beach really stand out is the combination of both the bowling balls and the amazingly straight and repeating bowling lanes that run right into the cliff face. While all sedimentary rocks are deposited laying fairly flat, these layer cake sandstones and mudstones were tilted upward by 90 degrees. If you look at the map above, you will see the San Andreas Fault is just to the east of Bowling Ball Beach. The uplift and tilting happened by movement and squeezing of the rocks along the San Andreas Fault system. Once tilted 90 degrees, slight differences in erosion of the layers make the lanes really stand out.

The “bowling alleys” of Bowling Ball Beach. As waves crash into the cliff, the sandstone erodes away and form the ‘lanes’. Photo courtesy of Ted from geologictrips.com.

English Muffin Rocks

In addition to the natural bowling alley, Bowling Ball Beach features what could be described as a giant game of shuffleboard. Towards the north end of the beach, a bed of gray shale hosts concretions that have been cemented by silica and resemble massive english muffins, five to six feet across. Some rest high up in the cliffside while others have slid down towards the sand like giant pucks in a game of vertical shuffleboard that has lasted for millennia.

The “muffin” rocks. Photo courtesy of Ted from geologictrips.com.

Have you visited Bowling Ball Beach or been to another beach with cool geologic concretions and stratifications? Let us know in the comments or on Facebook, and share photos if you have any!

Also, a special thank you to Ted of Geologic Trips for allowing Mobile Ranger to use his photos. Check out his website for a more detailed description of the geologic processes that formed Bowling Ball Beach.

Sources Used
- Geologic Trips, Sea Ranch and Bowling Ball Beach. Ted Konigsmark. GeoPress; 1995. http://www.geologictrips.com/sr/gtsr.pdf
- Bowling Ball Beach. http://www.geologictrips.com/bbb/bbb.pdf
- Compaction and Cementation. The Geological Society Website. http://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/page3559.html
- Bowling Ball Beach Redux. Phil Wendt Website. Published March 6, 2013. http://philwendt.com/2013/03/06/bowling-ball-beach-redux/

The Cool Staircase-Shaped Hills North of Santa Cruz

Ranger Gaudinski — Wed, 31 Dec 2014 00:00:09 +0000

This aerial photo taken about 3.5 miles north west of Western Drive on Highway 1 shows four marine terraces. The numbers correspond to the generally accepted numbering of each terrace—from the first marine terrace (agricultural fields) to the fourth (highest set). Picture © Kenneth and Gabrielle Adelman, California Coastal Records Project www.Californiacoastline.org

Have you ever wondered why much of the Westside of Santa Cruz and all the agricultural fields just north of it are so flat, or why many of the hills climb upwards like a staircase to flat tops? It’s because the local landscape is made up of ancient marine terraces, which formed as sea level rose and fell over the millennia. They are clearly visible from Western Drive north to Año Nuevo State Reserve.

The flat foreground is the first marine terrace. The second marine terrace is clearly visible. To the right of the middle white arrow, in the background, you can see the third.

The Santa Cruz marine terraces are a series of platforms cut into the ocean-facing slope of our local mountain (Ben Lomond Mountain). Each terrace is an ancient ocean floor that has since been slowly uplifted by large-scale tectonic movements. The higher the terrace, the older it is.

The first marine terrace is 105,000 years old and the fifth is about 550,000 years old. The steep surfaces that separate each terrace are old beach cliffs eroded away by waves during high stands in global sea level that occur during glacial cycles. The Westside of Santa Cruz and the many agricultural fields to the northwest are on the first marine terrace (also known as the Highway 1 Terrace). The second terrace parallels Highway 1 on the inland side all the way to Davenport. It is very easy to spot once you know it.

Map showing the Santa Cruz marine terraces. The purple is the first marine terrace. The blue is referred to here as the second, green the third, yellow the fourth and red the fifth marine terrace. The black arrow points to fifth marine terrace. Image is modified from a 2008 paper by Art White and colleagues on chemical weathering (listed at bottom).

How Do They Form?

Marine terraces can be found in many places around the globe but just the right conditions must be present for them to form. These are:

Slow and steady tectonic uplift (rates of about 0.02 inches per year)
Repeating cycles of rising and falling sea level (rise and fall of up to 400 feet!)
Just the right rate of erosion for a wave cut platform to form and a sea-cliff to be preserved

To understand how marine terraces are created, begin by thinking about the beaches of today. Each of the terraces you see once looked like a modern beach.

Schematic showing how a modern beach platform evolves into a marine terrace. Figure from a 2001 USGS paper by Gerald Webber and Alan Allwardt .

Normally, most of the ocean’s wave energy is used in leveling the wave-cut platform. But during winter storms and high tides large energetic waves erode into the sea cliff. In order for a marine terrace to form from a modern sea cliff, two things must happen:

Sea level falls by 10 to 100s of feet, leaving the cliff free from further wave erosion.
Continuous tectonic uplift then isolates it from the next high sea level stand.

Once the ocean recedes during a low stand in sea level, the process starts over again. The beach slowly rises becoming the new elevated sea cliff and terrace platform, and when the ocean advances again it slowly cuts a new wave-cut platform into the terrace. Erosional processes during uplift round out and bury much of the original beach deposits and sharp contours.

Another key factor is the erosion rate of the rock that makes up the mountain. It has to be hard enough to hold a cliff edge. In Santa Cruz, it is the Santa Cruz Mudstone that forms the modern sea cliffs and most of the marine terraces. It makes a hard and durable sea cliff that takes time to erode. In fact, the waves need to be focused in one location for a long time — thousands of years — to form a sea cliff. Also, sea level must rise at a rate just slightly greater than the tectonic uplift rate. If sea level rises too fast or too slow, wave action will not be focused on one location long enough to create a wave-cut platform and a sea cliff.

Geek Details: How Many Terraces and How Old?

The number of marine terraces found on Ben Lomond Mountain is still debated in scientific papers. Papers in the 1960s reported up to nine. Since the mid-1970s, five or six are generally reported. Part of the reason for the disagreement is that the higher terraces are older, more modified by erosion and harder to identify conclusively. Also, not all of the terraces run contiguously along the length of the coast. For example one terrace is found only in the Davenport area. It is above the Highway 1 Terrace but below the second terrace (as it is shown in the image above).

The ages of the terraces from youngest (lowest) to oldest (highest) are reported to be 105, 213, 320, 430 and 545 thousand years. Terrace age is debated in scientific studies, in large part because of the different dating methods used:

Uranium series dating, which measures the amount of short-lived decay products resulting from radioactive decay of Uranium in fossil corals and mollusks over time
Amino-acid racemization, which measures the degradation of proteins in fossilized organisms into suites of amino acids over time
Cosmogenic dating, which measures the buildup of beryllium-10 and aluminum-26, naturally occurring isotopes found in dust and known to be created at a fairly constant rate

Each method includes some unavoidable assumptions and has limitations. Their application to the terraces results in ages that vary 20-50 thousand years for the first terrace and 200+ thousand years for the third and higher terraces. I have given the ages from a 2001 paper by Gerald Webber and Alan Allwardt because the authors discuss all of the available studies and make a good case for their choices.

Sources Used
- Chemical weathering of a marine terrace chronosequence, Santa Cruz, California I: Interpreting rates and controls based on soil concentration–depth profiles. A F White, M S Schulz, D V Davison V. Vivit, et al. Geochimica et Cosmochimica Acta. 2008;72:36–68.
- The Geology from Santa Cruz to Point Año Nuevo—The San Gregorio Fault Zone and Pleistocene marine terraces. By Gerald Webber and Alan Allwardt. In: Stoffer PW, Gordon LC, eds. Geology and natural history of the San Francisco Bay Area: a field-trip guidebook: 2001 Fall Field Conference, National Association of Geology Teachers, Far Western Section: September 14-16. USGS Bulletin 2188; 2001:194.
- Living With the Changing California Coast. Gary B. Griggs, Kiki Patsch, Lauret E. Savoy. University of California Press; 2005.
- The Natural History of the University of California Santa Cruz Campus. Tonya M. Haff. Environmental Studies Department, University of California, Santa Cruz; 2008.
- The thaumatology of moving edges. Friends of the Pleistocene Worldnews.com.

Monterey Submarine Canyon: An Amazing Traveling Canyon!

Ranger Gaudinski — Thu, 11 Dec 2014 00:00:40 +0000

Picture the Grand Canyon under water. Then you’ll have the right scale in your mind when thinking about the Monterey Canyon in California. It is truly a huge underwater feature! It is the largest submarine canyon along the coast of North America.

Just Another River?

Initially scientists thought submarine canyons were carved like river canyons on land. They thought the process just happened at low stands in sea level during a glacial period, and that the canyon was later submerged during an inter-glacial period, when the sea level rose. The problem with this theory is that through all known glacial periods, sea level never dropped the required thousands of feet to expose the land so a river could carve the deep canyon.

Turbidity Currents to the Rescue

Today it has become clear that submarine canyons may indeed start forming during a low stand in sea level, like a normal river, but once sea level rises again, the main canyon cutting happens underwater by turbidity currents.
Turbidity currents are plumes of sediment (dense gravel, sand and mud) that rush downslope after being triggered by an earthquake or even large storms. In the picture above, red arrows indicate the general direction of sediment transport along the edges of the bay down into the canyon. The top-left arrow is from the San Lorenzo River, the center arrow is the Pajaro River and the right one is the Salinas River.

A Very Old Canyon

The Monterey Canyon is simply too deep and large to have been created by the sediments coming out from the current rivers. It was actually carved millions of years ago from a much larger load of sediment coming from California’s Central Valley. The canyon has moved away from its original drainage system as it moves northward along the San Andreas Fault at a rate of about 1.5 inches per year. Twenty five million years ago the canyon was 250 miles to the south and the local geography was very different! Deep sediments from cores within the canyon confirm that the sediment source used to be very far south of here.

Research in the Canyon

Much of the understanding of the Monterey Canyon comes from research done by the Monterey Bay Aquarium Research Institute (MBARI). MBARI specializes in combining scientific research with engineering design. This combination has allowed them to see and measure what no other scientists have seen and measured before — both within the Monterey Canyon, and all over the world.

Within the submarine canyon, MBARI uses underwater robots called remotely operated vehicles (ROVs) to explore and perform research experiments in the deep waters. The photo above shows a launch of the ROV Ventana on board the research vessel Point Lobos. Launching and recovering a 2-ton, 10-foot long ROV is a tricky business in the open waters of Monterey Bay.

A Home for Diversity

Submarine canyons extend from shallow to very deep waters, and thus contain a wide range of habitats and a very diverse array of organisms. Each habitat is home to its own set of fishes and invertebrates.

One example of an interesting creature is Vampyroteuthis infernalis, which means “vampire squid from hell.” It spends most of its time lurking in the always dark, low-oxygen waters about half a mile below the surface. It has a dark red body, huge blue eyes, and a cloak-like web that stretches between eight arms. If threatened, it will turn itself inside out, flaunting rows of evil-looking “cirri.”

Protecting the Canyon

Controlling pollution entering the Monterey Bay is very important to the health of the canyon ecosystem because it is the gravitational low point and is where trash and pollutants accumulate. Comparisons between surface and deep fish in the Monterey Canyon find deep fish to have much higher concentrations of persistent organic compounds such as PCBs and DDT.

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Liked the Article? Have a thought or comment about it? You can do so below, or even better…on our Facebook post about this topic.

Further Information

MBARI

Sources Used
- About MBARI.
- A Coast to Explore: Coastal Geology and Ecology of Central California. Miles O. Hayes, Jacqueline Michel. Pandion Books; 2010.
- Canyon Processes. Monterey Bay Aquarium Research Institute Website. http://www.mbari.org/canyon/.
- MBARI researchers discover what vampire squids eat (it’s not what you think). Monterey Bay Aquarium Research Institute Website.
- Our Ocean Backyard: Grand canyons on the seafloor. Gary Griggs. Santa Cruz Sentinel. November 21, 2009. http://www.santacruzsentinel.com/ci_13839171.
- Our Ocean Backyard: Submarine Canyons: Going Deeper. Gary Griggs. Santa Cruz Sentinel. December 19, 2009. http://www.santacruzsentinel.com/localnews/ci_13933346.
- Our Ocean Backyard: Why Monterey Submarine Canyon? Gary Griggs. Santa Cruz Sentinel. January 2, 2010. http://www.santacruzsentinel.com/ci_14109831.
- Our Ocean Backyard: Why Submarine Canyons? The Evidence Accumulates. Gary Griggs. Santa Cruz Sentinel. December 19, 2009. http://www.santacruzsentinel.com/news/ci_14031738.
- Monterey Bay National Marine Sanctuary Submarine Canyons. Simon: Sanctuary Integrated Monitoring Network. Sanctuary Simon.

Geology – Mobile Ranger

Greyhound Rock: Where’s the Hound?

Formation of the “Hound”

Creation of Santa Cruz Mudstone

Hardening to Rock

Take the Self-Guided Mobile Tour

Sources

Elkhorn Slough: Interface Between Land and Sea

Habitats and Wildlife at Elkhorn Slough

Moss Landing Harbor

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Sources

Waddell’s Wharf: Ordeals of Shipping Lumber from Año Nuevo Bay

A Tale of Two Wharves

It Ends with a Bear

Where to Look for Remnants of the Wharf

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Sources

Santa Cruz’s Nuclear Power Plant That Almost Was

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Caves and the Moving Lighthouses of Lighthouse Point

Original Lighthouse Had to be Moved

A Long Run Comes to an End

The New Lighthouse

Same Cave Problem

Further Information

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Sources

Surf’s up! Paleo Style

How Ancient Winds Formed The Wave

Sources

Mitchell Cove: Erosion of a Sea Stack

More Photos and Stories of West Cliff Drive Erosion

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Bonny Doon Beach: Railroads and Oil

Notice the Parking Lot

Grandiose Railroad Plans

A More Humble Reality

Why There Is a Tunnel

There’s Oil in Them Thar Hills!

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Sources Used

The Sandhills of Santa Cruz: There’s Shark Teeth Underneath

Endemism In The Hills

Discovering The Past

Sources Used

Bucking the Trend: Mount St. Helens Grows a Glacier

The Volcano that Made a Glacier

The Little Glacier that Could

Sources Used

California: Beauty of Tectonic Proportions

Plate Tectonics

The Sierra is Born

Creation of the San Andreas Fault

Sources Used

Racetrack Playa: Turtles Race Faster Than These Famed Stones!

Explaining the Sailing Stones

Slow and Steady

Sources Used

Historic Lime Kilns of UCSC

Cowell Lime Works

Lime Kilns (Pot Kilns)

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Sources Used

Below the Buildings: Karst and Construction at UCSC

Sink Hole Spotting

It’s San Andreas’ Fault

Where does the Water Go?

Building on Karst

Geek Details: Chemistry of the Karst

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Sources Used

The Rocks of Santa Cruz’s Central Coast: The Purisima Formation

Creation of the Purisima

The Purisima and Lighthouse Point

Caves Endanger Original Lighthouse

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Sources Used

The Huge Boulders Along the Santa Cruz Shoreline: A Common Coastal Story