How was the Entrada sandstone formed?
The Entrada Sandstone is a formation in the San Rafael Group found in the U.S. states of Wyoming, Colorado, northwest New Mexico, northeast Arizona, and southeast Utah. The Middle Jurassic San Rafael Group was dominantly deposited as ergs (sand seas) in a desert environment around the shallow Sundance Sea.
How was the Moab Valley formed?
Perhaps because of water running down along the fault line, salt was dissolved away deep under the rock of Moab. The overlying slab sunk down, creating a “collapsed anticline” that is the Spanish and Moab valley.
How were Utah arches formed?
The arches formed as the result of erosion through weak parts of sandstone fins composed of Jurassic-age Dewey Bridge Member of the Carmel Formation and Slick Rock Member of the Entrada Sandstone. Utah is also unique in its abundance of entrenched river systems, which often form spectacular natural bridges.
What type of rock is Navajo sandstone made of?
The rocks are predominantly composed of rounded quartz grains and were formed in a vast ancient desert of sand dunes, or erg, similar to the modern Sahara Desert. The Navajo Sandstone is one of the most extensive and most exposed aeolian (wind-blown) systems known in the geologic record.
How old is the Navajo sandstone?
~180 million years ago
Is Navajo sandstone well sorted?
Navajo Sandstone consists of well-sorted, rounded grains of translucent quartz, many of which are etched and frosted. This, together with the large-scale cross-bedding, indicates that the Navajo sediments accumulated in a vast desert which covered much of Utah, Arizona, and New Mexico during early Jurassic time.
What color is Navajo sandstone?
The range of colors of the Navajo Sandstone –red, brown, pink, salmon, gold, and even white—results from varying amounts and forms of iron oxide within the rock, and in the case of the white upper portion of the Navajo, the overall lack of iron.
What was the climate like at the time the Navajo sandstone was formed?
A vast area of sand dunes that stretched, at one time, from central Wyoming to the southeastern point of California left behind the sand that became Navajo Sandstone. The climate was much the same as the current Sahara desert, and the sand accumulated in a slowly sinking basin.
How old is the Carmel formation?
This ancient interior body of water, called the Sundance Sea by geologists, was warm, surrounded by an arid coastline, and bounded by sandy deserts to the south and the east. This map shows a depiction of Western North America during the deposition of the Temple Cap formation, ~170 million years ago.
Where is the Carmel formation?
The Carmel Formation is a geologic formation in the San Rafael Group that is spread across the U.S. states of Wyoming, Utah, Colorado, north east Arizona and New Mexico.
Where is the Chinle formation?
The Chinle Formation is part of the Colorado Plateau, Basin and Range, and the southern section of the Interior Plains. A probable separate depositional basin within the Chinle is found in northwestern Colorado and northeastern Utah. The southern portion of the Chinle reaches a maximum thickness of a little over 520 m.
Where is Kayenta Formation?
The Kayenta Formation is a geologic layer in the Glen Canyon Group that is spread across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah.
When was Kayenta Formation formed?
approximately 190 million years ago
What does Kayenta mean in Navajo?
: of or belonging to the northern Arizona branch of the Anasazi culture that provides a record from the period of the earth-lodge villages to the Great Pueblo centers.
How did the Morrison Formation form?
The deposits from their east-facing drainage basins, carried by streams and rivers from the Elko Highlands (along the borders of present-day Nevada and Utah) and deposited in swampy lowlands, lakes, river channels and floodplains, became the Morrison Formation.
What is the significance of the Morrison Formation?
The Morrison Formation is famous for its dinosaur fossils, which have been collected for more than a century, beginning with a find near the town of Morrison, Colorado, in 1877. Radiometric dating indicates that the Morrison Formation is between 148 million and 155 million years old.
What country found the largest dinosaur fossils?
Argentina
Where was allosaurus found?
Allosaurus, (genus Allosaurus), subsumes Antrodemus, large carnivorous dinosaurs that lived from 150 million to 144 million years ago during the Late Jurassic Period; they are best known from fossils found in the western United States, particularly from the Cleveland-Lloyd Quarry in Utah and the Garden Park Quarry in …
What is the biggest Allosaurus?
Allosaurus fragilis, the best-known species, had an average length of 8.5 m (28 ft), with the largest definitive Allosaurus specimen (AMNH 680) estimated at 9.7 meters (32 feet) long, with an estimated weight of 2.3 metric tons (2.5 short tons).
What did Allosaurus really look like?
Allosaurus had a short neck and a narrow, elongated skull, which was disproportionately large, similar to those of other big carnivorous theropods. But unlike other theropods, it had a pair of small horns above its eyes, which were extensions of the lacrimal bones in the skull.