Geology

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Geology of the Black Rock Desert area

Web Sites

Black Rock Desert Specific Sites

  • Nevada Bureau of Mines and Geology
    The Nevada Bureau of Mines and Geology (NBMG) is a research and public service unit of the University of Nevada and is the state geological survey. NBMG scientists conduct research and publish reports on mineral resources, engineering geology, environmental geology, hydrogeology, and geologic mapping. Current activities in geologic mapping and mineral resources include detailed geologic mapping and stratigraphic studies in Nevada, comparative studies of bulk-mineable precious-metal deposits, geochemical investigations of mining districts, metallic and industrial mineral resource assessments, igneous petrologic studies, hydrothermal experiments, and research on the origin of mineral deposits.
  • The Tufas of Pyramid Lake, Nevada
    "Pyramid Lake is the site of some of the Earth's most spectacular tufa deposits. The Tufas are composed of calcium carbonate (CaCO3). The large tufa mounds, reef- and sheet-like tufas formed within Pyramid Lake, between 26,000 and 13,000 years (yr) ago, when the lake was part of pluvial Lake Lahontan. The mounds are composed of large interlocking spheres that contain multiple generations of a crystalline (thinolite) variety of tufa. Over time many of the mounds have fallen apart, exposing an internal network of tubes. The tubular structures are thought to have been created when springs discharged from the bottom of Pyramid Lake, supplying calcium that combined with carbonate dissolved in lake water to form the mounds. The reef- and sheet-like deposits contain pillow and pendant forms made up of a branching variety of tufa that often grades into dense layers or nodules. Dense layers of tufa also coat cobbles and boulders that were deposited in near-shore shallow-water areas. The thickest tufa deposits formed at lake-bottom sites of ground-water discharge and at overflow elevations1 where the lake was held at near-constant levels for long periods of time."

Black Rock Desert Mammoth

Black Rock Desert Arrowheads

Black Rock Desert Meteorites

Black Rock Desert Geological Maps

Earthquakes

Desert Geology

  • Archaebacteria cyanobacteria, stromatolites, Desert Varnish, Thermophilic and Halophilic Bacteria, thermophilic eubacteria

Papers

  • Anderson, J.P., 1977, A geological and geochemical study of the southwest part of the Black Rock Desert and its geothermal area; Washoe, Pershing, and Humboldt Counties, Nevada [M.S.]: Colorado School of Mines.
  • Adams, Kenneth D., Wesnousky, Steven G. and Bills, Bruce G., "Isostatic rebound, active faulting, and potential geomorphic effects in the Lake Lahontan basin, Nevada and California," GSA Bulletin, v. 111, no. 12, p 1739-1756, December 1999.
    "The high shoreline of the late Pleistocene (Sehoo) lake in the Lahontan basin is used as a passive strain marker to delineate the magnitude and character of regional deformation since 13 ka. The elevations of 170 high shoreline sites document that the once horizontal (equipotential) shoreline, which traverses almost 4° of latitude and 3° of longitude, is now deflected vertically about 22 m. Most of the deformation is attributed to isostatic rebound, but a small down-to-the-north regional tilting also appears to contribute to the overall deformation pattern. Active faults locally offset the high shoreline, but cannot explain the regional upwarping attributed to isostatic rebound since 13 ka. Preliminary models of the rebound yield an upper mantle viscosity of 1018 Pa s that implies a Maxwell relaxation time of about 300 yr. The rapid Earth response, coupled with the rapid fall in lake level at the end of Pleistocene time, may have acted to divert some of the major rivers flowing into the basin from one terminal subbasin to another. The regional deformation caused by the rebound may also have acted to control the present location of Honey Lake. These shoreline data, therefore, support the potential for a link between climate change, deep Earth processes, and surficial processes."
  • Crewdson, Robert A., 1976, Geophysical studies in the Black Rock Desert geothermal prospect, Nevada [Ph.D.]: Colorado School of Mines, 366 p.
  • Dodge, Rebecca Lee, 1982, Seismic and geomorphic history of the Black Rock fault zone, northwest Nevada [Ph.D.]: Colorado School of Mines, 271 p.
  • Gianella, V. P., and Larson, E. R., 1960, Marine Permian at Black Rock, Nevada: Geol. Soc. Amer, Bull., v. 71, p. 2061.
    "Black Rock, a prominent topographic feature of the Black Rock Desert in northwest Nevada, was first reported by John C. Fremont who, in 1844, noted the abundance of black fragments, like the cinders from a blacksmith's forge, at the base of this sharply conical hill.
    The rock, generally thought to be a mass of volcanic-flow rock, received only cursory attention over the years. Recent detailed examination has shown the cone to be composed of very steeply dipping, fossiliferous, volcanic sediments and limestones. The fossiliferous beds contain well-preserved upper (?) Permian brachiopods. This is the westernmost exposure of fossiliferous Permian strata known in the State.
    The Black Rock Permian consists of more than 1800 feet of volcanic sediments with variable amounts of limestone and includes a 100-foot unit of well-bedded limestone. The major portion of the sequence is 1- to 2-foot beds of andesite clasts which average about half an inch in diameter but range from a small fraction of an inch to 6 inches. The volcanic rocks consist principally of augite andesite breccia.
    The volcanic sediments at Black Rock are typical of accumulations in eugeosynclines. In these belts local volcanic sources may supply volcanic detritus to adjacent areas of limestone deposition. In some fortuitous circumstances, as at Black Rock, organic remains are preserved in the more limey beds and in the dominantly volcanic detritus."
  • Howe, Daniel Marshall, 1975, Correlation of the fauna from the Middle Permian section at Black Rock, northwestern Nevada [M.S.]: Univ. Nevada, Reno, 133 p.
  • Maher, Kevin A., "Geology of the Jackson Mountains, northwest Nevada," Ph.D. Thesis, California Institute of Technology, 1989.
    "The Jackson Mountains are located in the western Great Basin in Humboldt County, northwest Nevada. The range contains a late Paleozoic to Mesozoic depositional sequence. This sequence records sedimentation, volcanism and deformation in a back-arc setting. The Mississippian to late Early Permian McGill Canyon Formation was deposited in basinal to slope to distal shelf environments, dominated by hemipelagic and turbiditic facies. In the Permian there was an volcanic arc andesite component, and a nearby contemporaneous carbonate platform shed olistostromes into the unit. The McGill Canyon was laid down in an area between the McCloud arc and the Havallah back-arc basin. The late Middle Triassic to middle Norian Bliss Canyon Formation was laid down in basinal to fore-reef to carbonate platform to lagoonal to terrigenous littoral environments. Both of these formations are of flap sequences deposited on an east-facing, back-arc margin. The Bliss Canyon represents the western margin of the Early Mesozoic marine basin of the western Great Basin. From the late Norian to the Bathonian, several stages of subearial volcanism and alluvial epiclastic sedimentation laid down the Happy Creek Formation, a thick arc andesite volcanic pile. The Happy Creek is part of the Early Mesozoic Cordilleran magmatic arc province. In the Bathonian, this volcanic pile was cut by a conjugate sinistral high-angle wrench fault system as volcanism waned. During the Callovian, sediments of the King Lear Formation filled in and then overlapped the wrench basins. These sediments were derived from the east, where a west-vergent thrust system was active. This phase of thrusting ceased by the Oxfordian. Arc-related silicic volcanism and alluvial to fluvial sedimentation within the King Tear continued into the Aptian, when the thrusts were reactivated during a second phase. Both phases of thrusting verged both east and west. Stocks, dikes and sills of the Early Mesozoic Intrusive suite are comagmatic with the volcanism in the Happy Creek and King Lear, and intrude the sedimentary units. This suite both plugs and is truncated by the wrench faults and the first phase of thrusting, but is cut by the second phase. The Jackson Mountains are part of the Black Rock terrane in northwest Nevada. Within this terrane, the rocks share a common tectonic history and stratigraphy distinct from the neighboring terranes, and are separated from them by Mesozoic thrust and strike-slip faults."
  • Meyer, Cari, Negrini, Robert M., Ewing, Inge, Edwards, Kathy, and Herrero-Bervera, Emilio, "A Paleoclimate Record from The Black Rock Desert Subbasin of Lake Lahontan: 23,000-12,000 C-14 YR B.P," Cordilleran Section - 97th Annual Meeting, and Pacific Section, American Association of Petroleum Geologists (April 9-11, 2001).
    Three cores were taken from the northeastern--most arm of the Black Rock Desert in NW Nevada in order to determine the paleoclimate through time in this subbasin of Pleistocene Lake Lahontan. A variety of analyses have been performed on the cores including C-14 dating, tephrochronology, preliminary faunal analysis of ostracodes, measurement of paleomagnetic directions and of sediment magnetic parameters. The magnetic parameters include susceptibility, anhysteretic and isothermal remanent magnetizations, the S-parameter, and the anisotropy of magnetic susceptibility. Further analyses currently underway are the measurement of total organic and inorganic carbon, trace element geochemistry using ICP-MS instrumentation, x-ray diffraction work, granulometry and a more detailed ostracode analysis.
  • Neal, James T., 1970. Playa Surface Features as Indicators of Environment, Proc. 1970 Playa Lake Symposium, Texas Tech Univ.
    "Recognition of surface features on playas is an important element in determining their geologic character and utilization potential because they can reveal some aspects of the physical environment. Moreover, surface features are usually identifiable on air photos and from some remote sensing data, enabling their recognition from a distance. Some features form conspicuous, regular patterns, whereas others are of local extent and randomly ordered."
    "Groundwater discharge through playa surfaces, or the lack of it, can often be inferred by the recognition of playa surface types. Phreatophyte growth around playa perimeters is an important indicator, but more subtle are soft, friable surfaces with a saline efflorescence. Thicker evaporate crusts are normally associated with greater groundwater discharge. Playa surfaces of moderate groundwater discharge can be readily modified through dissolution by surface water."
  • Sunzeri, C.C., 1975, The lean brown land; a study of the relationship between landform and plant ecology in the Black Rock Desert [M.S.]: Univ. California, Santa Cruz.
  • Welch, Alan Herbert, 1985, Geothermal resources of the western Black Rock Desert, northwestern Nevada; hydrology and aqueous geochemistry [Ph.D.]: Univ. Nevada, Reno, 150 p.
  • Wyld, Sandra J., Wright, James E., Kinsella, Margaret E., and Warren, Mark Benjamin, "Identification of a Distinct Terrane in the Cordillera that is Offset Along the Early Cretaceous Dextran MSNI Fault System," Geological Society of America, Cordilleran Section - 103rd Annual Meeting (4–6 May 2007), Bellingham, Washington.
    "Mapping along the Nevada-southeast Oregon portion of the MSNI fault (this portion previously called the western Nevada shear zone; Wyld and Wright, 2001) has identified several lithotectonic assemblages that are clearly out of place with respect to geologic provinces to the east. These include (in Oregon) the Middle Jurassic continental arc assemblage of the Pueblo Mountains, and (in Nevada) Permian volcanogenic rocks at Black Rock Point, Permian and early Mesozoic carbonate, clastics and bimodal volcanogenic rocks in the Granite Range, and an assemblage of argillite, quartzite and carbonate in the Fox Range that is at least in part Late Triassic or younger. Quartzites from the Fox and Granite Ranges have a detrital zircon age signature identical to that of Jurassic erg sandstones of the Colorado plateau."

See Also