Stratigraphy In 1941, the US Department of Interior, which runs the National Park service, commissio

StratigraphyIn 1941, the US Department of Interior, which runs the National Park service, commissioned nature photographer Ansel Adams to provide photographs for the walls of the Interior Department’s new headquarters in Washington, DC. The project was never finished due to the United States’ entry into the Second World War, but the already-captured photographs were still property of the Interior Department.The US National Archives has made over 200 of these files available online. They cover many major stops in the western US, including Grand Canyon, Yosemite, Yellowstone, Carlsbad Caverns, Kings Canyon, Grand Teton, and Rocky Mountain National Parks.The pile of sedimentary layers that is the Grand Canyon is laid open by the Colorado in this shot by Adams. Look at how you can track the entire 300 million year sequence – from the sandstone atop the Great Unconformity to the Kaibab Limestone at the top. Really impressive how the Coconino Sandstone, a deposit of cross bedded sand dunes, stands out even at this distance, and how you can spot a slight hint of slope to the uppermost surface.-Image credit: Dept. of the Interior/National Archiveshttps://www.archives.gov/research/ansel-adams/ -- source link

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