The Paradox Basin is an asymmetric

foreland basin A foreland basin is a structural basin that develops adjacent and parallel to a mountain belt. Foreland basins form because the immense mass created by crustal thickening associated with the evolution of a mountain belt causes the lithospher ...

located mostly in southeast Utah and southwest Colorado, but extending into northeast Arizona and northwest New Mexico. The basin is a large elongate northwest to southeast oriented depression formed during the late Paleozoic Era. The basin is bordered on the east by the tectonically uplifted Uncompahgre Plateau, on the northwest by the San Rafael Swell and extends partway into the Monument Uplift to the west. Its area is roughly 33,000 square miles (85470 km²). The combined sedimentary

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

of the Paradox Basin are more than 15,000 feet (4600 m) thick in some places. Unlike most Rocky Mountain basins, the Paradox Basin is an evaporite basin containing sediments from alternating cycles of deep marine and very shallow water. As a result of the thick salt sequences and the fact that salt is ductile at relatively low temperatures and pressures, salt tectonics play a major role in the post-

Pennsylvanian Pennsylvanian may refer to: * A person or thing from Pennsylvania * Pennsylvanian (geology) The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timesca ...

structural deformation within the basin.

History

Scientists believe the seawater at the base of Paradox Basin may have been trapped there for several hundred million years. However, in 2022 researchers attempting to date the basin unexpectedly discovered relatively "young" water as far down as three kilometers (1.9 miles). "The fresh influx would have been delivered by rainfall, snow melt or natural aquifers as recently as between 400,000 and 1.1 million years ago."

Natural resources

Natural resources extracted from the basin include petroleum, uranium, copper, and potash. Much of the petroleum production in the basin has come from porous carbonate deposits, such as algal mounds, of Pennsylvanian age. Additional reservoir types include uplifted fault blocks and discontinuous

clastic Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks ...

beds with both stratigraphic and structural traps. The principal productive horizons in the basin include the

Mississippian Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period in the geologic timescale, roughly 360 to 325 million years ago *Mississippian culture, a culture of Native American mound-builders from 900 to 1500 AD ...

Leadville Limestone, the Pennsylvanian

Hermosa Group The Hermosa Group is a group of geologic formations in Utah and Colorado. It preserves fossils dating back to the Carboniferous period. See also * List of fossiliferous stratigraphic units in Utah * Paleontology in Utah The location of the st ...

(

Honaker Trail The Honaker Trail is a hiking trail located near Goosenecks State Park in southeastern Utah. Built in the late 1890s and early 1900s as a supply route for gold prospectors, the trail connects the deeply entrenched San Juan River with the canyo ...

, Paradox, and Pinkerton Trail formations) and the Permian age Cutler Formation. Discoveries in the Cane Creek Shale of the Paradox Formation have resulted in new oil production near Moab, Utah.

References

{{coord, 38, N, 109, W, display=title Geologic provinces of Colorado Geology of Utah Sedimentary basins of North America