GeoSights
Explore Utah’s lesser-known geologic wonders.
Earth Science Week is celebrated the second full week of October throughout the nation as well as in other countries. The purpose is to increase public understanding and appreciation of the Earth sciences. Launched in 1998 by the American Geosciences Institute, efforts have grown on local, national, and international levels to highlight the vital role Earth sciences play in society’s use of resources and interaction with the environment.
Learn about the Earth and its processes with this self-guided experience into Earth science topics, created by the UGS for teachers, parents, students, and the public.
Select a subject below to open the informational video.
Rocks & Minerals
Geology is the study of Earth as it pertains to the composition, structure, and origin of its rocks. Rocks are classified based on how they formed and what minerals are in the rock. Minerals are classified by their chemical composition.
Rocks vs. Minerals
From the United States Geological Survey the difference between rocks and minerals is defined as:
Teaching Materials & Publications
Interactive Maps
Christian HardwickUtah Rockhounder
Collect rocks, minerals, fossils, and landscape rocks.
Dinosaurs & Fossils
There are a wide variety of fossils native to Utah. Some of the most common fossils are of marine life like shells, coral, and trilobites. Plant and other land-based fossils are also native to Utah and include dinosaurs, Ice Age animals, and leaves.
Utah in the Age of Dinosaurs
Dinosaurs lived only during the Mesozoic Era, which is often called the “Age of Dinosaurs.” Utah has perhaps the best Mesozoic rock record in the world.
The Mesozoic Era (252 to 66 million years ago) is divided into three time periods:
Triassic Period – 252 to 201 million years ago
The first dinosaurs lived near the end of the Triassic. Eoraptor, a bipedal carnivore recently discovered in South America, is the earliest known dinosaur.
Triassic dinosaurs have not yet been found in Utah. Late Triassic rocks known as the Chinle Formation are exposed throughout southern and eastern Utah, as well as Arizona and New Mexico. This rock unit has yielded abundant remains of the carnivorous (meat-eating) dinosaur Coelophysis in Arizona and New Mexico. Although no Triassic dinosaurs have been discovered in Utah, the state hosts a plethora of dinosaur fossils, so it is only a matter of time before Triassic-age fossils are found.
Jurassic Period – 201 to 145 million years ago
During the Early and Middle Jurassic, Utah was mostly desert, although periodically sea level would rise and the sea would invade this sand dune-covered landscape. The great sandstone cliffs of Zion and Arches National Park are basically fossil sand dunes. Although dinosaur footprints are known from many sites in Utah, no dinosaur skeletons have yet been found in these desert rocks. Marine reptiles have been found in marine rocks near Dinosaur National Monument.
Most of Utah’s well-known dinosaur fossils are Late Jurassic dinosaurs. They are found mainly in a rock unit known as the Morrison Formation which dates to approximately 150 million years ago.
Dinosaurs are divided into two major groups, the saurischian, or “lizard-hipped,” dinosaurs and the ornithischian, or “bird-hipped,” dinosaurs.
- The saurischian dinosaurs include the herbivorous (plant eaters), quadrupedal sauropods, and the carnivorous, bipedal theropods.
- The ornithischian dinosaurs are all herbivorous and are composed of many groups, including stegosaurs, ornithopods, and ceratopsians.
Birds evolved from a group of the saurischian theropods known as coelurosaurs.
Dinosaur fossils from the Morrison Formation can be found in Utah at the Dinosaur National Monument quarry in northeastern Utah and at the Cleveland-Lloyd Dinosaur Quarry in east-central Utah. Allosaurus is Utah’s State Fossil. Allosaurus is a carnivorous theropod found in abundance at the Cleveland-Lloyd Dinosaur Quarry.
Cretaceous Period – 145 to 66 million years ago
Early Cretaceous dinosaur fossils are found in Utah in the Cedar Mountain Formation, which dates to about 125 to 98 million years ago. This rock unit overlies the Morrison Formation, but represents more time and contains several entirely different faunas or groups of dinosaurs. These rocks represent a time when North America was connected to Europe before flowering plants, a period when rising sea levels led to the isolation of North America from the rest of the world, and finally a time when the first land connections with Asia were established and flowering plants had come into their own. The Cedar Mountain Formation is the basis of considerable research by UGS paleontologists.
Late Cretaceous dinosaurs such as Tyrannosaurus and Torosaurus lived about 65 million years ago at the end of the age of dinosaurs. Cretaceous dinosaur sites are found in great abundance in Montana and Alberta, Canada, and are also found in the North Horn Formation of central Utah. Further south in the Grand Staircase – Escalante National Monument the most continuous record of Cretaceous dinosaurs in the world has now been recognized and research is just beginning to bring these many undescribed Utah dinosaurs to light.
Tracks & Tracksites
Tracks and tracksites are types of trace fossils, also called ichnofossils, which are imprints left behind by an animal.
A Glimpse into the past
Artist conception of the plants and animals living in the Jurassic Navajo erg (sand sea). Note the two Tritylodons and their Brasilichnium trackways. Illustration by Russell Hawley.
Tracks and Tracksites
Examples of tracks include claw marks, dewclaws, footpads, skin impressions, and tail drags. Tracks and other trace fossils can be good evidence for the size and identity of the animals that made them. Behaviors like eating habits, migration paths, and walking mechanics can also be inferred from some tracks if they are preserved well.
How are Tracks Formed and Preserved?
During times when the water levels dropped on shallow lake shores, swamps, coastal areas, and rivers, the animals walked in the mud along the shore, leaving footprints that then filled in with silt and sand – all of which later hardened into stone. Thus, many of the tracks are preserved as bumps (natural casts) instead of impressions. The track casts are mostly found on the underside of a sandstone layer that overlies the mudstone in which the tracks were formed.
Where are Tracks and Tracksites Located in Utah
In Utah, tracks can be found in many places like the St. George Dinosaur Discovery Site at Johnson Farm and at Flaming Gorge Reservoir, among other places. Visit our interactive map to locate and visit some tracksites for yourself!
Dinosaur and Fossil Photos
Click on the photos below to view them full-screen with descriptions.
In this video, make observations on what shapes form and change in this river in different environments. What recurring shapes do you see? The different colored “sediments” represent more- or less-heavy material. Where do the different colors get deposited compared to each other?
Stream Erosion
Rivers or streams behave as systems. If one part of the stream channel is disturbed, changes will occur in the upstream and downstream direction. Stream tables are used in experiments where geologists can learn more about how rivers form, change, and affect surrounding rock and sediments. Geologists also use satellite imagery to piece together a stream channel’s history and infer its future.
Helpful Definitions:
- EROSION – The process by which soil and rock are removed from one area of the Earth through natural causes such as wind, water, and ice and transported elsewhere.
- DEPOSITION – The geological process where material is added to a landform.
- DELTA – A piece of land in the shape of a triangle or fan made by sediment deposited at the mouth of a river.
- FLOODPLAIN – Low, flat land along a stream that is flooded when the stream overflows.
- MEANDER – A curve in a river. Meanders form a snake-like pattern as the rivers flow across fairly flat valley floors.
- BRAIDED RIVER – A river that has lots of small channels that continually split and join. Braided rivers are usually wide but shallow.
- OXBOW LAKE – A U-shaped lake created when a meander of a river is cut off as the river erodes a new path.
Stream Table Demos
Real-World Changing River System – Ucayali River, Peru
Stream Erosion Photos
Click on the photos below to view them full-screen with descriptions.
Earthquakes & Hazards
Geologic hazards are geologic conditions that may cause substantial loss or damage to property, damage to the environment and economy, health risks, injury, or even death. Geologic hazards that affect Utah include earthquakes, landslides, flooding, problem soils and rocks, and volcanic hazards. We can live and deal with geologic hazards by understanding what they are, where they exist, how large or difficult they are, and how to effectively mitigate them.
Utah has experienced 17 earthquakes greater than magnitude (M) 5.5 since pioneer settlement in 1847, and geologic investigations of our region’s faults indicate a long history of repeated large earthquakes of M 6.5 and greater prior to settlement.
Utah Earthquakes Story Map
Geologic Hazard Photos
Click on the photos below to view them full-screen with descriptions.
Teacher Resources
Learn more about our teacher resources at the UGS.
View all teaching materials and topics from the UGS.
LEARN MORE ABOUT THE UTAH GEOLOGICAL SURVEY
The Utah Geological Survey (UGS) is a division of the Utah Department of Natural Resources. Several specialized programs comprise the UGS: Data Management, Energy & Minerals, Geologic Hazards, Geologic Information & Outreach, Geologic Mapping, Groundwater & Wetlands, and Paleontology.
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Salt Lake City, Utah 84114
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