Written in Stone

Another Lens on Life blog from Chuck Kopczak, PhD

11/16/2020
Mostly barren, rounded rocks, pictured in black and white to show contrast and detail
Chuck Kopczak, PhD

Layers of sandstone bent into vertical walls at Devil's Punchbowl near Pearblossom, California

This photo was taken with a Canon EF28-135 mm f/3.5-5.6 IS USM lens zoomed to 120 mm on a Canon EOS 5D Mk III. The exposure was set to 1/750 sec at f/5.6 and ISO 400.

Devil’s Punchbowl is a Los Angeles County Natural Area located on the north side of the San Gabriel Mountains, near the town of Pearblossom, California. The Punchbowl is the major feature of the park, being a folded sandstone formation that resulted from the geological processes that formed the surrounding mountains. Starting about 60 million years ago, continuous movement along five or six different fault zones along with erosion led to the rise of the San Gabriel Mountain, and extensive folding, of which the Punchbowl is one of the most obvious features.

The canyon that is the Punchbowl is approximately 300 feet deep with very steep sides. Geologists call it a plunging syncline, which simply means a downward fold with very steep sides. The letter V is a reasonable illustration of a plunging syncline, or you can create your own by folding a piece of paper into a sharp V shape. The once horizontally oriented sediments that became the sandstone of the Devil’s Punchbowl formation were deposited about 13 million years ago, before being squeezed into solid form, and then slowly, but violently thrust upward to form the rock walls we see today. That violence is evidenced by the fact that it took only a million years to raise the San Gabriel Mountains to their current elevations. While that seems like an extremely long time to us, it is little more than the blink of an eye in geological terms.

Today’s photo is of the south wall of the Punchbowl taken on a frigid morning in late December. My eye was attracted to the various textures, tones and shapes of the fractured sandstone crags. The snow coating the rocks provides a sharp contrast to the varying tones of the sandstone faces, and highlights the texture of some of the rocks. A few small trees, like determined sentinels, cling to the rock cliffs. The fracture lines describe further shapes within the larger stone faces, while the smaller boulders are like prisoners just escaped from the surrounding stone prison walls.

Source

https://parks.lacounty.gov/devils-punchbowl-natural-area-and-nature-center/