Part 2: The Death Valley Racetrack and Sailing Stones
As I started writing my post and podcast on Death Valley’s geologic history, I found so many other fun things I wanted to talk about. Today’s podcast is more physics than geology and focuses on the Death Valley Racetrack and Sailing Stones. Now, when I think of a racetrack, I immediately picture cars driving an oval at fast speeds. And so, when I originally heard that Death Valley had a racetrack, I thought “oh, they must have raced cars here many years ago.” not even really thinking about the logistics of how cars might have made the travel to this remote location. The racetrack is remote and an over 2-hour drive from the nearest filling station today. I cannot even contemplate how a vehicle would have gotten fuel if it was a racetrack for vehicles. So, not a vehicle racetrack but a racetrack for rocks?!
The mystery of the Death Valley racetrack and sailing stones has fascinated me for years. The Racetrack Playa is an isolated and remote valley 27 miles away from Ubehebe (oo-be-he-be) Crater where the paved road ends. The Racetrack Playa is a dry lakebed. At the end of the last glacial maximum, approximately 10,000 years ago, the Racetrack Playa underwent several climatic cycles of heating and cooling. Eventually, the glacial lake evaporated and left behind a dry lakebed with a base of 1,000 feet deep of beige mud.
The rock trails in the Racetrack Playa were first documented in 1915 by the prospector, Joseph Crick, who was out scouting new mineral localities. Joseph showed the rock trails to his wife, who went out with him and marked the locations of the rocks. Over time, the Cricks repeatedly checked on the locations, and low and behold the rocks had moved away from the original marks. The lakebed became known as the Racetrack Playa and the stones as “The Sailing Stones' due to the fact they appear to move or sail on their own accord. The Racetrack Playa lies at the base of an 850-foot mountain face of dolomite. The stones themselves are primarily igneous syenite (western part of the playa), banded dolomite, or black dolomite, the most common stone found in the Southern half of the playa. They are all weathered fragments of the parent rock slopes that surround the Racetrack. The playa base is covered in mud cracks that range in diameter up to 4 inches and contain 1-inch-deep cracks. The cracks form as the mud surface dries and shrinks.
The racetrack lies between the Cottonwood and Last Chance Ranges and is a “playa” or a dry lakebed. If you recall in Episode 1, I spoke about Glacial Lake Panamint. Glacial Lake Panamint existed just to the south of the Racetrack Playa during the late Pleistocene ice age which ended around 10 or 11, 000 years ago. The Saltpans and playas in the area were created as the ice age glaciers retreated. When the playa floods it gets a new layer of mud on the surface and when that dries and the water in the soil evaporates it forms new cracks.
If you look at an aerial of the area you can see that the sailing rocks have left parallel tracks, as if they have moved at the same time, they also show similar changes in direction. These tracks can range in length from 10's to 100's feet long. One track was measured by Robert Sharp in 1997 to be 1,982 feet long and other researchers have reported even longer tracks. The stones themselves might not move for years.
The playa floor also displays little elevation change and from the direction of some of the trails, the rocks have moved “uphill” on some occasions. The rock trails also appear to change direction. After Crick’s initial discovery and study, the sailing stones have been studied by numerous groups throughout the years. The National Parks Service and Life Magazine also produced an article on the stones in March 1952. No one had seen the stones move in person.
The stones themselves range in size from "a computer mouse to a microwave" and are followed by a trail in the lakebed, much like the contrail of an airplane. The tracks range in length from a few feet to longer than a football field.
Explanations for the movement range from the scientific to the absurd. Magnetism, aliens, mysterious energy fields, magic, you name it. In 1948, two US Geological Survey Geologists Jim McAllister and Allen Agnew proposed that the playa's intermittent flooding and dust devils were causing them to move. The hypothesis was tested in later years but was inconclusive. In the 1970s another pair of Geologists Robert Sharp and Dwight Carey meticulously tracked the movements of 30 of the stones. the pair even gave them names, Karen was the largest boulder at 700 pounds. I want to apologize to all the Karens out there, you guys get a bad rap!
Several additional experiments were conducted in the following decades to rule out ice and wind and most of the wind-based models were really thrown into doubt when researchers calculated that the winds needed to move the stones would be equal to aircraft speeds of hundreds of miles per hour. We entered the new century with still a lot of questions about how the stones were moving. Enter the Norris cousins.
The Norris Experiment
In 2011, two cousins, Richard and Jim Norris set up some experiments to solve why the rocks moved. They set out their own rocks with GPS transmitters within them that would activate when the rock moved. These transmitters were also connected to a remote weather station so that correlations between the weather and the moving rocks could be made. It took two years before the GPS trackers activated and it occurred on a day that they never expected them to move. Previous journals and experiments had indicated there were two dominant hypotheses for the Sailing Stones. The first, strong powerful winds, the second, ice. What was observed by the Norris cousins was that the Playa fills with water after a rain event, and on cold nights that water will freeze and form thin sheets of ice, like plate glass. As that ice begins to melt the next day in the heat of the Sun, it creates a thin layer of water which reduces the friction between the rocks and the playa floor. The wind then drags the sheets of the ice with the rocks encased in them across the playa on that thin layer of water creating the rock trails. So, it was actually both ice and wind that caused the rocks to move. What was surprising was that the ice was only ⅛ of an inch of ice. The rocks moved for only 15 minutes before the ice all melted away. (Ray, 2014)
This event is typically observed by and is called a seiche (saysh). A seiche is a standing wave oscillating in a body of water. They are often called mini-tsunamis or storm surges. A seiche event occurs, in the case of Death Valley, as the wind moves the entire pond uphill and then when the wind dies the pond recedes.
The NOAA figure below represents a seiche. The black waves represent the standing wave and the red and the blue waves represent propagating waves in opposite directions. Seiches can occur in any enclosed body of water such as a pond, lake, swimming pool, or in this case a dry lakebed.
On October 19, 1844, a "Great Seiche" occurred on Lake Erie. The water in Buffalo reportedly rose to 22 feet high or to the second story of buildings. When the waters receded, and the lake level returned to equilibrium it pulled houses off their foundations and as many as 79 residents of Buffalo drowned in the seiche. Over 100 ships were damaged and railroad tracks around Buffalo were pulled up. Reports of the Niagara River changing colors 25 miles downstream towards Niagara Falls and Lake Ontario were reported in newspapers.
In the classroom, you can demonstrate the phenomena of a seiche using a fish tank of water. You will want your tank to be thermally stratified as our surface water bodies are, cold at the base and warm at the top. Layer your tank with cold water (dyed blue) at the bottom and then room temperature water (dyed red) and finally hot water (dyed green to represent algae in the photic zone) to model thermal stratification. Use a fan or a hairdryer to blow across the surface of the tank to represent surface wind. Shut the fan off and observe how the layers change.
In larger bodies of water, seiche events have an impact on fishing. As you can observe from the fish tank demonstration, the thermal stratification of the water changes. Wind drives cooler water across the lake. Cooler water is denser than warmer water, so it sinks which forces an upwelling of nutrient-rich water toward the surface. More nutrients mean more food for fish and fish follow the warmer water. We see this demonstrated with El Niño and La Niña events as upwelling increases and decreases respectively. These conditions do not currently affect the Playas in California and Nevada, but they would have played a role during the glacial time and as the waters were receding from the glacial lakes.
Turns out Death Valley is not the only place these sailing rock events have occurred. A similar event of sailing rocks has been observed and studied at Little Bonnie Claire Playa in Nye County, Nevada. Bonnie Claire, the town is a legitimate ghost town that contains relics of its mining history. The last resident of Bonnie Claire left in the '50s. Little Bonnie Claire Playa is located approximately 40 miles north of Beatty, Nevada. Bonnie Clair is a similarly shaped playa to the Racetrack residing between the Slate Ridge, Amargosa Range Mountains, and Grapevine Mountains. This salt flat is actually a bit more accessible than the Racetrack Playa. It is approximately 20 miles east of Scotty's Castle in Death Valley, about a half-hour ride, when the roads are open. The Bonnie Claire Playa resides between the park boundary and 10 miles west of Highway 95. The Shore side of the Bonnie Clair Playa runs alongside the northbound side of Highway 267 in Nevada in an area of the state managed by the Bureau of Land Management (BLM). Bonnie Claire Road, Route 267 is currently closed due to construction to repair the roadway and culverts from flooding. When I was researching, I did come across articles on a company that had leased some of the salt flats in the area of Bonnie Claire to mine lithium carbonates. I cannot confirm where the mining operations are occurring in relation to the sailing rocks in the salt pan. If you are still feeling adventurous you can visit the Bonnie Clair Gold Mountain Mining Camp as well in the area. If you hike Gold Peak, you can be one of the few who have signed the register that was placed on the peak in the 1998s by Gordon MacLeod and Barbara Lilley. Since its placement, on average 1-2 people per year sign the register.
If you are going to visit the Racetrack Playa begin your journey at Furnace Creek. It is about an hour from the Ubehebe Crater down a rough dirt road. This road is no joke, make sure you have full-size spare, all-terrain tires for the sharp rocks, high clearance, and 4WD. Use the Boy and Girl Scout motto, BE PREPARED. A few suggestions to be prepared:
Full tank of fuel or a backup can with fuel.
Bring a can of fix a flat,
A 12-volt air compressor,
Make sure your vehicle has the lug wrench and car jack. (You wouldn't believe how many vehicles no longer come with these key items.)
Make sure you have an emergency first aid kit (the ambulance is not reaching you here.)
Bring LOTS of water and snacks.
To access the Racetrack Playa, drive north from Furnace Creek on Scotty's Castle Road to the Grapevine Ranger Station. Check-in and notify the rangers of your plan to access the Racetrack. Take a left onto Ubehebe Crater Road. At the end of the parking area take the unpaved Racetrack Valley Road and travel for about an hour south-southwest until you reach the Grandstand parking area. From the Grandstand, drive 2 miles south you will see a left-hand path to the east that is best accessed by foot into the salt pan. The National Parks Service indicates that the best viewing for the stones is about a half-mile walk toward the southeast corner of the playa.
Do not disturb the rocks or their tracks. After a rain, the playa can become muddy so stay on the roadway and paths so that you do not leave any footprints. Leave no trace. Driving off established roads is prohibited. Currently, as I write this much of this area of the park is still closed due to flooding that occurred earlier this month. Scotty's Castle has been closed since 2015 from a severe flood and then later structural fire in April 2021. The flood left mud and debris up to 10 feet deep and took out the utilities.
If you have any questions about Death Valley National Park and the geologic features and processes, I mentioned in this article, contact me here. I leave you with a quote from Henry David Thoreau
“In wilderness is the preservation of the world.”
References
California Division of Mines and Geology. (2009, July 24). California Division of Mines and Geology Special Report 106 Geologic Features—Death Valley, California. California Division of Mines and Geology: Special Report 106 - Geologic Features—Death Valley, California (Contents). Retrieved April 30, 2022, from http://npshistory.com/publications/geology/state/ca/cdmg-sr-106/contents.htm
Miller, I. (2011). Two-stage formation of Death Valley. Geosphere, 7(1), 71-82. https://pubs.geoscienceworld.org/gsa/geosphere/article/7/1/171/132406/Two-stage-formation-of-Death-Valley
Miller, M. (2015). Geology of Death Valley: Landforms, Crustal Extension, Geologic History, Road Guides. Kendall Hunt Publishing Company.
National Parks Service. (2022, January 9). Geology - Death Valley National Park (US National Park Service). National Park Service. Retrieved April 30, 2022, from https://www.nps.gov/deva/learn/nature/geology.htm
Norris RD, Norris JM, Lorenz RD, Ray J, Jackson B (2014) Sliding Rocks on Racetrack Playa, Death Valley National Park: First Observation of Rocks in Motion. PLoS ONE 9(8): e105948. https://doi.org/10.1371/journal.pone.0105948
Ray, J. (2014, August 27). Mystery Solved: "Sailing Stones" of Death Valley Seen in Action for the First Time. Scripps Institution of Oceanography |. Retrieved April 30, 2022, from https://scripps.ucsd.edu/news/mystery-solved-sailing-stones-death-valley-seen-action-first-time
What is a seiche? (2021, March 3). National Ocean Service. Retrieved June 27, 2022, from https://oceanservice.noaa.gov/facts/seiche.html
Scientific Vocabulary
Seiche - a standing wave oscillating in a body of water
Playa - dry lake bed
Saltpans - the evaporite deposits that precipitate out of an evaporating lake bed. Salt pans form when the evaporation rate exceeds the precipitation rate like in a desert
Dolomite- sedimentary rock in the carbonate family that has a high percentage of the mineral dolomite CaMg(CO3)2.
Syenite- coarse-grained intrusive igneous rock that is similar in composition to granite but has NO quartz.
Standing Wave- also called a stationary wave was first observed by Michael Faraday in 1831. occurs when two waves combine that have the same amplitude and frequency but in opposing directions
upwelling
El Niño - trade winds push warm waters across the Pacific, causing upwelling off Peru and the Pacific Northwest
La Niña - opposite conditions as El Nino, cold water pushed across Pacific, upwelling slows or stops
Lithium carbonates - mineral mined from underground brine solutions in carbonate salt deposits. The lithium salt Li2CO3 used in the processing of metal oxides as a precursor mineral to producing lithium ions for lithium-ion batteries. Lithium has also been used in the treatment of mood disorders. Lithium carbonate is also used to create red color in fireworks displays.