Sip back as we explore the fossils of Utah in the USA. The Carnegie Quarry was first discovered in 1909 and is found within Dinosaur National Monument only a 3 hour drive along the I-80 E and US-40 E/U.S. Hwy 40 E from Salt Lake City on the Utah-Colorado border in the USA. Operated by the Intermountain Natural History Association the Carnegie Quarry dinosaur bone site is a remarkable destination for both fossil lovers and visitors alike to discover up close an exceptionally preserved natural history tableau of large vertebrate dinosaurs held in a wall of sandstone. The Carnegie Quarry Exhibit wall holds a collection of over 1,500 bones from nine dinosaurs including Stegosaurus, Diplodocus, Camarasaurus, Apatosaurus and Allosaurus in a setting of three bone beds or layers separated by boundaries caliche indicating dry periods. The bones of the dinosaurs would have been washed down and deposited in the multiple channels and bars of silts, sands, gravels and larger stones of a Late Jurassic braided river system dating back nearly 151 million years ago in what is known now as the Morrison Formation.
The Carnegie Quarry in Utah was discovered in 1909 by Earl Douglass a field collector for the Carnegie Museum. This initial discovery was only a few years after the expeditionary exploits of Major John Wesley Powell who led a company of men down the Green and Colorado rivers in 1869.
This followed the earlier settlement in Salt Lake Valley by Mormon pioneers led by the religious leader Brigham Young in 1847 at a time that saw the transition of this region from being a once Mexican territory in to becoming a U.S. territory in 1848 after the Treaty of Guadalupe Hidalgo which ended the Mexican-American War.
Under the terms of this Treaty, Mexico was to give up significant land territory to the United States, including California, Nevada, Utah, New Mexico, Texas and most of Arizona and Colorado, and parts of Oklahoma, Kansas, and Wyoming. The Rio Grande river would become the natural border between the United States and Mexico.
Utah was finally admitted by United States Congress into the Union as the 45th state in January 1896. This marked the culmination of nearly five decades of settlement, governance, and compromise by the Mormon community and other settlers in the region.
It was upon this historical back drop that huge areas of the west were opened up to exploration and settlement. By 1915 President Woodrow Wilson established Dinosaur National Monument to protect the scientific integrity of the quarry and in 1922 the Carnegie Museum gave up its claim to the quarry to become Federal land and in 1958 the National Park Service enclosed the unexcavated area of the Carnegie Quarry within a building with accessible exhibits and research facilities.
The Morrison Formation is only one of 27 non-overlapping sequential faunal levels of Mesozoic Era rock in Utah that according to the Utah Friends of Palaeontology and the Utah Geological Survey has yielded 115+ dinosaur species and still counting.
The Morrison Formation is an important stratigraphic unit from the Late Jurassic Epoch dated between 164 to 145 million years ago located in the Western United States including significant portions of Utah. Formed in a variety of depositional environments, including rivers, floodplains, and lakes it is renowned for its rich fossil record and time when the climate was significantly warmer than it is today.
The Morrison Formation was named by English geologist Arthur Lakes who discovered dinosaur bones near to the town of Morrison, Colorado in 1877, setting off the “dinosaur bone rush” in Colorado and the American West and his fossil finds are believed to have been a trigger to the late 19th-century "Bone Wars" between rival palaeontologists Othniel Charles Marsh and Edward Drinker Cope. These early discovers by Arthur Lake in Morrison included bones of large sauropods like Apatosaurus and Stegosaurus.
The Morrison Formation is composed of a variety of sedimentary rocks, including sandstones, mudstones, siltstones, and conglomerates. These deposits reflect a range of environments, from river channels and floodplains to lakes and swamps. The diverse lithology provides evidence of dynamic geological processes, including erosion, sediment transport, and deposition by rivers, streams, and intermittent lakes. The formation’s colours range from reddish-brown to greenish-grey, reflecting variations in the mineral content and oxidation states of iron within the sediments.
During the Late Jurassic the region that is now Utah was part of a vast, semi-arid landscape characterised by seasonal rainfall and ephemeral waterways. The Morrison Formation represents deposits from a low-lying floodplain environment, interspersed with rivers, lakes, and wetlands. These water sources were critical for the diverse flora and fauna of the time.
The Morrison Formation is part of the larger Cordilleran foreland basin system, which formed as tectonic forces uplifted the Rocky Mountains. The sediments that comprise the formation were derived from erosion of these highlands and transported by rivers and streams into the basin. Over time, these sediments were compacted and lithified into the rock layers we see today.
In Utah, the Morrison Formation is widely exposed in other destinations worth exploring including the Jurassic National Monument at the Cleveland-Lloyd Dinosaur Quarry, the Arches National Park, and along the San Rafael Swell Recreation Area. These exposures not only offer stunning landscapes but also provide invaluable opportunities to explore a Late Jurassic ecosystem.
The Morrison Formation is one of the most important sources of dinosaur fossils in the world and Utah hosts some of its most celebrated exposures. The Morrison formation has yielded fossils from a wide array of massive sauropods as well as carnivorous theropods along with the fossils of plants, freshwater invertebrates and trace fossils like footprints to provide a broader ecological context of our understanding of the time.