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Capitol Reef National Park in south-central Utah. May 2, 2022.
In the Utah desert, the purple rocks, cliffs, and canyons of this nautically named nationwide park—and plenty of of its well-known fossils—owe their existence to water.
Capitol Reef National Park in south-central Utah shouldn’t be house to both a capitol or a reef. It was named as a substitute for 2 geologic options: the outstanding white domes of Navajo Sandstone, which reminded early settlers of the Capitol Building in Washington, D.C.; and a formidable ridge of rocky cliffs that offered a barrier to passage. The settlers (some doubtless touring in prairie schooners) in contrast it to the maritime navigational hazard of an ocean reef.
The ridge, known as Waterpocket Fold, runs north-south for 90 miles (140 kilometers). It is seen within the picture above, which was acquired on May 2, 2022, by the Landsat 9’s Operational Land Imager-2 (OLI-2).
The ridge is called for a standard characteristic within the park. Waterpockets are pure depressions or pockets—eroded from the rock—that accumulate rainwater and snowmelt, a valuable supply of freshwater for people and wildlife within the desert. Geologically, Waterpocket Fold is a monocline, a construction through which the rock layers have been folded up or down on one aspect. (Structures through which the rock layers are folded on each side—both bent up like a U-shaped smile or down like frown—are known as synclines and anticlines, respectively.)
Between 75 million and 35 million years in the past, the tectonic forces that uplifted the Rocky Mountains additionally buckled older rocks under Capitol Reef. The rock layers above didn’t break, however bent, like a tablecloth draped over a desk edge. The bend on this drape kinds the Waterpocket Fold. More lately, rains, flash floods, and freeze-thaw cycles have eroded and sculpted the cliffs, canyons, bridges, and domes into what we see at present.
Capitol Reef tells a geologic story of a whole bunch of thousands and thousands of years of deposition, uplift, and erosion—punctuated by episodes of volcanism and glaciation. The park boasts a virtually full collection of rock layers spanning from the late Permian Period (about 290 million years in the past) to the tip of the Mesozoic Era (66 million years ago). Deposited along and in a shallow sea and ancient delta, these rocks hold a nearly continuous record of life and environments here from before the rise of the dinosaurs through their demise.
Today, they are some of the most well-known rocks of the Colorado Plateau, including the Moenkopi, Chinle, Navajo, Entrada, and Dakota formations. Several of these are visible in the below image of Big Thomson Mesa within Capitol Reef. The photograph was taken on June 14, 2009, by the crew on the International Space Station.
Big Thomson Mesa. June 14, 2009.
Capitol Reef also hosts part of the largest and oldest fossil megatracksite in North America. These are mostly trace fossils, or ichnofossils, found in the Moenkopi Formation, which formed in the Early Triassic Period, about 240 million years ago. Unlike body fossils, trace fossils are the marks or other evidence that ancient life left behind—like footprints, burrows, and even feces (coprolites). Many of the trackways at Capitol Reef were formed when fish dragged their fins or reptiles scraped their feet, toes, or claws as they swam along an ancient shoreline or traversed a tidal mudflat. The impressions that they left were later filled with sand, which hardened into sandstone, forming casts.
In May 2022, park officials reported the loss of part of a rare fossil trackway. After posting a photo of a rock outcrop on social media, park officials were alerted to the missing tracks by a paleontologist who was familiar with the site. An examination of previous photos of the site revealed the fossils had been removed sometime between August 2017 and August 2018.
NASA Earth Observatory image by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Astronaut photograph ISS020-E-9861 was acquired on June 14, 2009, with a Nikon D3 digital camera fitted with an 800 mm lens, and is provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Center. The image was taken by the Expedition 20 crew. The image in this article has been cropped and enhanced to improve contrast. Lens artifacts have been removed. The International Space Station Program supports the laboratory to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet.
