More than 33,000 feet (10,000 metres) of generally conformable upper Precambrian (present in the subsurface), Paleozoic, and Lower Triassic strata, all overlain in profound unconformity by Oligocene and younger volcanic and sedimentary rock, are present in the Confusion Range of west-central Utah. During the late Mesozoic to early Cenozoic, the pre-Tertiary rocks were deformed into a structural trough or synclinorium concave in map view to the west. The development of the trough generated two decollement-type faults, above which rocks glided toward its axis. This gliding resulted in the formation, in the highest plate, of isoclinal and recumbent folds, the latter with their lobes directed into the axis. After the trough was filled, additional steepening of the west flank caused the develo~ ment of a lower decollement that died out eastward toward the axis of the trough. Movement of this decollement caused local overturning of the intermediate and upper plates and a more pronounced westward concavity of the trough. Subsequent increase ofthe slope of the flanks of the trough, whether by uplift or compression, achieved relief of axial stress by thrusting away from the axis of the trough.
Hot springs are numerous and nearly uniformly distributed in northern Most occur on the flanks of basins, along Basin and Range (late Surface temperatures of the springs range from slightly above Nevada. Miocene to Holocene) faults, while some occur in the inner parts of the basins. ambient to boiling; some springs are superheated. water temperatures calculated on the basis 6 f quartz solubility range as high as 252OC, although most are below 190OC. to several hundred liters per minute. Maximum subsurface Flows range from a trickle The Nevada geothermal systems differ markedly from the power-producing system at The Geysers, Calif., and from those areas with a high potential for power production (e.g., Yellowstone Park, Wyo.; Jemez Mountains, N. Mex.). These other systems are'associated with Quaternary felsic volcanic rocks, and probably derive their heat from cooling magma rather high in the crust. In northern. Nevada, however, felsic volcanic rocks are virtually all older than 10 million years, and analogous magmatic heat sources are, therefore, probably lacking. Nevada is part of an area of much higher average heat flow than the 'rest of the United States. In north-central Nevada, geothermal gradients. are as great as 64OC per kilometer in bedrock and even higher in basin fill. The,high gradients probably result from a combination of thin crust and high temperature upper mantle.. We suggest that the geothermal systems of northern Nevada result from circulation of meteoric waters along Basin and Range faults and that their temperature chiefly depends upon (1) depth of circulation and (2) the geothermal gradient near the faults.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.