Mystery Of Crowley Lake Columns Solved
Rising like ancient ruins along the eastern shore of Crowley Lake in Mono County, California, the Crowley Lake Columns are among the most visually striking and scientifically intriguing geological formations in the eastern Sierra Nevada. Towering up to 20 feet high and arranged in tight rows and arches, these unusual stone pillars were shaped not by human hands, but by a rare combination of volcanic activity, hydrothermal convection, and mineral cementation that began over 760,000 years ago.
The Long Valley Caldera Eruption
The story of the Crowley Lake Columns begins with one of the most powerful volcanic eruptions in the geologic history of North America. Around 760,000 years ago, the Long Valley Caldera erupted catastrophically, releasing over 150 cubic miles of volcanic material. This super-eruption blanketed the eastern Sierra Nevada and Owens Valley with hot pyroclastic flows—dense clouds of gas, ash, and pumice that eventually settled and solidified into a thick deposit of rhyolitic tuff.
This tuff, rich in silica and still intensely hot after deposition, formed the bedrock into which the Crowley Lake Columns would later emerge.
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| Crowley Lake Columns – Mono County, California |
The Formation Process: Not Columnar Jointing
Contrary to popular belief, the Crowley Lake Columns are not a result of classical columnar jointing—the type of contraction cracking seen in cooling lava flows like those at Devil’s Postpile. Instead, they were formed by a hydrothermal convection process within the freshly deposited volcanic ash.
Shortly after the eruption, snowmelt and groundwater began to seep into the still-hot tuff. This cold water sank, was heated, and then rose back up as steam—creating vertical convection cells similar to heat pipes. Within these cells, amorphous silica, zeolites, and iron-rich minerals precipitated and cemented the tuff into hardened vertical columns. Over tens of thousands of years, these cemented zones resisted erosion, while surrounding material was gradually worn away.
The result: nearly 5,000 columns standing today, some bent, some curved, many appearing as though chiseled by human hands—yet they are purely the product of geology.
.jpg "Towering tuff columns at Crowley Lake, formed by ancient steam-induced fracturing and mineral cementation in volcanic ash deposits.") |
| Towering tuff columns at Crowley Lake, formed by ancient steam-induced fracturing and mineral cementation in volcanic ash deposits. |
Scientific Investigation and Discovery
Although local anglers and hikers had noticed the columns since the mid-20th century, their origin remained a mystery until a study led by Noah Randolph-Flagg, a Ph.D. candidate at UC Berkeley, provided new insight. Through microscopic analyses and X-ray imaging, researchers found that the columns were formed by hydrothermal mineralization along vertically aligned convection cells. These cemented regions were composed of silica and secondary minerals like mordenite, a zeolite that forms under specific temperature and pH conditions.
“The Crowley Columns are a rare natural experiment in hydrothermal convection,” said Randolph-Flagg. “They reveal how volcanic terrains continue to evolve long after the eruption ends.”
The research, supported by the U.S. Geological Survey (USGS), also helped reconstruct past environmental conditions in the caldera, shedding light on post-eruption climate, groundwater systems, and volcanic thermal gradients.
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| Shoreline section of Crowley Lake with exposed volcanic columns, formed by geothermal mineral deposition in solidified ash layers. |
Physical Characteristics: What Do They Look Like?
There are an estimated 5,000 columns within a 2- to 3-square-mile area east of the lake. Many stand straight and cylindrical, spaced closely together like pipe organs. Others are tilted, bent, or even partially buried, giving the appearance of fossilized dinosaur vertebrae or ancient architectural ruins.
Most columns are gray or reddish-orange, depending on their mineral content and degree of oxidation.
They are often marked with horizontal striations, spaced roughly 12 inches apart—possibly reflecting pauses in mineral precipitation or layers of different permeability.
Columns vary in height but can reach up to 20 feet, and some are interconnected by natural arches.
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| Towering Crowley Lake volcanic columns in Mono County, formed by Pleistocene-era hydrothermal cooling fractures in rhyolitic tuff. |
Access and Preservation
The Crowley Lake Columns are located approximately 10 miles south of Mammoth Lakes, accessible via Owens Gorge Road from Highway 395. The final approach requires either a 4WD vehicle or a moderate 2-mile hike across sandy terrain with little shade. Visitors should prepare accordingly—there are no facilities, and conditions can be harsh in both summer and winter.
While the site remains open to the public, geologists and conservationists caution visitors to avoid climbing on or damaging the fragile structures. Though they appear solid, the columns are susceptible to breakage and erosion. Educational tours organized by the Los Angeles Department of Water and Power (LADWP) and university groups are beginning to raise awareness about the site's scientific value.
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| Aerial view of Crowley Lake's striking volcanic stone columns in California, formed by ancient geothermal activity in hardened ash deposits. |
Why the Crowley Columns Matter
The Crowley Lake Columns are a rare example of hydrothermal cementation in volcanic ash, a process not typically visible at the surface. Their formation reveals how post-eruption environments can produce complex and unexpected rock textures. The site also underscores the ongoing interaction between water, heat, and rock—a dynamic system that shapes volcanic landscapes for tens of thousands of years after an eruption.
As research continues, scientists hope to apply findings from Crowley Lake to similar deposits in other volcanic regions, including New Mexico, Iceland, and Mexico, where tuffaceous rocks exhibit unusual internal textures but lack the exposure seen here.
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| Pleistocene-era volcanic columns at Crowley Lake, Mono County. |
Key Facts at a Glance
- Location: Eastern shore of Crowley Lake, Mono County, CA
- Age: ~760,000 years (Long Valley Caldera eruption)
- Composition: Rhyolitic tuff with silica and zeolite cementation
- Formation Process: Hydrothermal convection, not columnar jointing
- Number of Columns: Estimated ~5,000
- Size: Up to 20 feet tall, spaced ~1 ft apart
- Color: Gray to red-orange
- Best Time to Visit: Fall and spring, when lake levels are low
- Access: 4WD or ~2-mile hike; no public facilities
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Eastern perspective of Crowley Lake's Pleistocene-era basalt columns, showcasing hexagonal jointing from volcanic cooling fractures. |
Visiting the Crowley Lake Columns
To reach the columns:
- Travel south from Mammoth Lakes on Highway 395 for about 10 miles.
- Turn east toward Crowley Lake via Rock Creek Road, then follow access roads to the shoreline.
- The columns can be accessed by foot, boat, or four-wheel-drive vehicle, depending on lake levels and trail conditions.
- A 0.5-mile hike leads to the main clusters, rated as moderately difficult due to loose footing and seasonal variation.
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| Close-up of Crowley Lake column interiors, revealing rare hydrothermal mineralization patterns in volcanic tuff from Pleistocene eruptions. |
Photographers often find the geometric patterns of the columns fascinating, especially when they're partially submerged or when the light hits them at certain angles, creating dramatic shadows and reflections.
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Crowley Lake's dramatic hydrothermally cemented tuff columns. |
Visitors interested in geology, natural formations, and photography often find the Crowley Lake Columns to be a captivating destination, showcasing the beauty and intricacies of volcanic geological processes.
