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The Paradox Basin is an asymmetric foreland basin located mostly in southeast
The Paradox Basin is an asymmetric foreland basin located mostly in southeast Utah
Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...
and southwest Colorado
Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...
, but extending into northeast Arizona
Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fo ...
and northwest New Mexico
)
, population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano)
, seat = Santa Fe
, LargestCity = Albuquerque
, LargestMetro = Tiguex
, OfficialLang = None
, Languages = English, Spanish ( New Mexican), Navajo, ...
. The basin is a large elongate northwest to southeast oriented depression formed during the late Paleozoic Era
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ''z ...
. The basin is bordered on the east by the tectonically uplifted Uncompahgre Plateau
The Uncompahgre Plateau in western Colorado is a distinctive large uplift part of the Colorado Plateau. is a Ute word that describes the water: "Dirty Water" or "Rocks that make Water Red".
The plateau, with an average elevation of , rises fro ...
, on the northwest by the San Rafael Swell
The San Rafael Swell is a large geologic feature located in south-central Utah, United States about west of Green River. The San Rafael Swell, measuring approximately , consists of a giant dome-shaped anticline of sandstone, shale, and limesto ...
and extends partway into the Monument Uplift to the west.
Its area is roughly 33,000 square miles (85470 km2). The combined sedimentary
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
strata of the Paradox Basin are more than 15,000 feet (4600 m) thick in some places.
Unlike most Rocky Mountain
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
basins, the Paradox Basin is an evaporite
An evaporite () is a water-soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as ocean ...
basin containing sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, san ...
s 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 temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer.
Thermometers are calibrated in various temperature scales that historically have relied o ...
s and pressures, salt tectonics play a major role in the post- Pennsylvanian 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 naturalaquifers
An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...
as recently as between 400,000 and 1.1 million years ago."
Natural resources
Natural resources extracted from the basin includepetroleum
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...
, uranium
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...
, copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish- ...
, and potash.
Much of the petroleum production in the basin has come from porous carbonate
A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate g ...
deposits, such as algal
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthesis, photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from u ...
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 Leadville Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms wh ...
, the Pennsylvanian Hermosa Group ( Honaker Trail, Paradox
A paradox is a logically self-contradictory statement or a statement that runs contrary to one's expectation. It is a statement that, despite apparently valid reasoning from true premises, leads to a seemingly self-contradictory or a logically u ...
, and Pinkerton Trail formations) and the Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
age Cutler Formation.
Discoveries in the Cane Creek Shale of the Paradox Formation have resulted in new oil production near Moab, Utah.
See also
*Paradox Valley
Paradox Valley is a basin located in Montrose County in the U.S. state of Colorado. The dry, sparsely populated valley is named after the apparently paradoxical course of the Dolores River—instead of flowing down the length of the valley, ...
, which gave the basin its name
References
{{coord, 38, N, 109, W, display=title Geologic provinces of Colorado Geology of Utah Sedimentary basins of North America