Earth Observations taken by the Expedition 15 Crew

ISS015-E-28004 (12 Sept. 2007) --- A section of Dinosaur National Monument along the Yampa River in Colorado, which straddles the Colorado/Utah border, is featured in this image photographed by an Expedition 15 crewmember on the International Space Station. Dinosaur National Monument is perhaps best known for the abundant fossils found in the approximately 145 Ma (mega-annum, or millions of years old) Morrison Formation exposed in valleys and low ridges, according to scientists. The fossil assemblage is a unique record of terrestrial life of the period (dinosaurs, plants, and other animal species). Remains accumulated in streams and shallow lakes and were swiftly buried (and preserved) by sediments associated with those environments. Scientists believe these sediments in turn were lithified over many millions of years as they were buried under younger deposits -- forming the distinctive stratigraphy of the Monument. The generally flat-laying "layer cake" geology of the region -- similar to the Colorado Plateau to the south - is expressed in the image by parallel beds of tan, reddish-brown, and gray-brown sedimentary rocks cut by the Yampa River at the northern end of the Monument (top). Erosion by the Yampa River exposed the Morrison layer and its trove of fossil material. Together with other fossils found in both older and younger rock layers in the area, the Dinosaur National Monument remains an important scientific resource that continues to provide new insights into the geologic history and paleoecology of the region.