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At least 37 records · Page 2Linked to original sources
USGS2017

Tectonic Speleogenesis of Devils Hole, Nevada, and Implications for Hydrogeology and the Development of Long, Continuous Paleoenvironmental Records

Devils Hole, in southern Nevada, is a surface collapse into a deep, planar, steeply dipping fault-controlled fissure in Cambrian limestone and dolostone. The collapse intersects the water table about 15 m below land surface and the fissure extends at least 130 m deeper. Below water, most of the fissure is lined with a >30-cm-thick layer of dense maxillary calcite that precipitated continuously from groundwater for >500,000 yr. The thick mammillary calcite coat implies a long history of calcite-supersaturated groundwaters, which, combined with the absence of dissolutional morphologies, suggests that Devils Hole was not formed by karst processes. Devils Hole is located in a region of active extension; its tectonic origin is shown by evidence of spreading of its planar opening along a fault and by the orientation of its opening and others nearby, perpendicular to the northwest-southeast minimum principal stress direction of the region. Most Quaternary tectonic activity in the area, including seismicity and Quaternary faults and fractures, occurs on or parallel to northeast-striking structures. The hydrogeologic implications of this primarily structural origin are that fracture networks and caves opened by extensional tectonism can act as groundwater flowpaths functionally similar to those developed by karst processes and that, during active extension, transmissivity can be maintained despite infilling by mineral precipitation. Such extensional environments can provide conditions favorable for accumulation of deposits preserving long, continuous paleoenvironmental records. The precipitates in Devils Hole store chronologies of flow system water-level fluctuations, hydrochemistry, a half-million-yr proxy paleoclimate record, evidence of Devils Hole's tectonic origin, and probably atmospheric circulation.

Quaternary Research↗
USGS1982

Reconnaissance geology of the Manjamah Quadrangle, sheet 18/41 A, Kingdom of Saudi Arabia

The Manjamah quadrangle (sheet 18/41 A) lies between lat 18?30' and 19?00' N. and long 41?00' and 41?30' E. and encompasses an area of 2,932 km2, of which about half is land and the remainder covered by the Red Sea. The geologic formations exposed in the quadrangle comprise Precambrian layered and intrusive rocks,. Tertiary layered rocks and gabbro dikes, and. Quaternary basaltic lavas, pyroclastic rocks, and surficial deposits. The Precambrian rocks are layered metasedimentary and metavolcanic rocks that have been assigned to the Baish and Bahah groups. These rocks are cut by Precambrian biotite quartz monzonite and by Miocene gabbro dikes that were intruded during the initial stages of the opening of the Red Sea rift. Tuffaceous siltstone of the Baid formation was also deposited during the Miocene, followed in the Pliocene by the polymict conglomerate of the Bathan formation. The Quaternary rocks include basalt that was extruded during a continuation of the opening of the Red Sea rift, after uplift of the escarpment parallel with the Red Sea but before the Holocene erosional cycle. The greater part of the land area of the quadrangle is covered by Quaternary coastal, pediment, and alluvial deposits of various kinds associated with the deltaic mouths of Wadi Hall and Wadi Yiba and their tributaries and with the development of fringing reefs and islands. The area also contains extensive Quaternary eolian deposits. The economic potential of the quadrangle lies essentially in the agricultural value .of its flood-plain deposits, which are frequently refreshed during flooding with the products of weathering and erosion of the Precambrian rocks in the valleys of Wadi Hal i and Wadi Yiba; coral reefs could possibly provide raw material for use in a cement industry, if any such industry were ever required in this area.

Open-File Report↗
USGS2006

Maps of quaternary deposits and liquefaction susceptibility in the Central San Francisco Bay Region, California

This report presents a map and database of Quaternary deposits and liquefaction susceptibility for the urban core of the San Francisco Bay region. It supercedes the equivalent area of U.S. Geological Survey Open-File Report 00-444 (Knudsen and others, 2000), which covers the larger 9-county San Francisco Bay region. The report consists of (1) a spatial database, (2) two small-scale colored maps (Quaternary deposits and liquefaction susceptibility), (3) a text describing the Quaternary map and liquefaction interpretation (part 3), and (4) a text introducing the report and describing the database (part 1). All parts of the report are digital; part 1 describes the database and digital files and how to obtain them by downloading across the internet. The nine counties surrounding San Francisco Bay straddle the San Andreas fault system, which exposes the region to serious earthquake hazard (Working Group on California Earthquake Probabilities, 1999). Much of the land adjacent to the Bay and the major rivers and streams is underlain by unconsolidated deposits that are particularly vulnerable to earthquake shaking and liquefaction of water-saturated granular sediment. This new map provides a consistent detailed treatment of the central part of the 9-county region in which much of the mapping of Open-File Report 00-444 was either at smaller (less detailed) scale or represented only preliminary revision of earlier work. Like Open-File Report 00-444, the current mapping uses geomorphic expression, pedogenic soils, inferred depositional environments, and geologic age to define and distinguish the map units. Further scrutiny of the factors controlling liquefaction susceptibility has led to some changes relative to Open-File Report 00-444: particularly the reclassification of San Francisco Bay mud (Qhbm) to have only MODERATE susceptibility and the rating of artificial fills according to the Quaternary map units inferred to underlie them (other than dams - adf). The two colored maps provide a regional summary of the new mapping at a scale of 1:200,000, a scale that is sufficient to show the general distribution and relationships of the map units but not to distinguish the more detailed elements that are present in the database. The report is the product of cooperative work by the National Earthquake Hazards Reduction Program (NEHRP) and National Cooperative Geologic Mapping Program of the U.S. Geological Survey, William Lettis and & Associates, Inc. (WLA), and the California Geological Survey. An earlier version was submitted to the U.S. Geological Survey by WLA as a final report for a NEHRP grant (Witter and others, 2005). The mapping has been carried out by WLA geologists under contract to the NEHRP Earthquake Program (Grant 99-HQ-GR-0095) and by the California Geological Survey.

Open-File Report↗
USGS1966

Geology of the Cupsuptic quadrangle, Maine

The Cupsuptic quadrangle, in west-central Maine, lies in a relatively narrow belt of pre-Silurian rocks extending from the Connecticut River valley across northern New Hampshire to north-central Maine. The Albee Formation, composed of green, purple, and black phyllite with interbedded-quartzite, is exposed in the core of a regional anticlinorium overlain to the southeast by greenstone of the Oquossoc Formation which in turn is overlain by black slate of the Kamankeag Formation. In the northern part of the quadrangle the Albee Formation is overlain by black slate, feldspathic graywacke, and minor greenstone of the Dixville Formation. The Kamankeag Formation is dated as 1-ate Middle Ordovician by graptolites (zone 12) found near the base of the unit. The Dixville Formation is correlated with the Kamankeag Formation and Oquossoc Formation and is considered to be Middle Ordovician. The Albee Formation is considered to be Middle to Lower Ordovician from correlations with similar rocks in northeastern and southwestern Vermont. The Oquossoc and Kamankeag Formations are correlated with the Amonoosuc and Partridge Formations of northern New Hampshire. The pre-Silurian rocks are unconformably overlain by unnamed rocks of Silurian age in the southeast, west-central, and northwest ninths of the quadrangle. The basal Silurian units are boulder to cobble polymict conglomerate and quartz-pebble conglomerate of late Lower Silurian (Upper Llandovery) age. The overlying rocks are either well-bedded slate and quartzite, silty limestone, or arenaceous limestone. Thearenaceous limestone contains Upper Silurian (Lower Ludlow) brachiopods. The stratified rocks have been intruded by three stocks of biotite-muscovite quartz monzonite, a large body of metadiorite and associated serpentinite, smaller bodies of gabbro, granodiorite, and intrusive felsite, as well as numerous diabase and quartz monzonite dikes. The metadiorite and serpentinite, and possibly the gabbro and granodiorite are Late Ordovician in age. The quartz monzonite is considered to be Late Devonian. Five tectonic events are inferred from the structural features in the area. The earliest was a period of folding producing tightly-appressed, northeast-trending folds in the rocks of pre-Silurian age. In the second stage the folded pre-Silurian rocks were uplifted, eroded, and truncated to produce a major unconformity between the Middle Ordovician and Lower Silurian rocks. These events constitute the Taconic orogeny. The third tectonic event was a period of folding, probably of Middle Devonian age, that warped the unconformity and overlying rocks into open, gently-plunging, east-trending folds. This period of folding undoubtedly changed the attitude of the early folds in the pre-Silurian units but it did not produce any recognizable, cross-cutting planar features in the older rocks. The fourth tectonic event was a period of igneous intrusion that locally deformed the northeast-trending folds in the pre-Silurian rocks into a macroscopic drag fold plunging at 80 degrees in a direction S.10?w. A north-trending, subvertical slip cleavage was produced locally during this period of Late Devonian (?) deformation. A period of faulting, possibly of Triassic age, dislocated some of the earlier features. The rocks are in the chlorite zone of regional metamorphism, but have been contact metamorphosed to sillimanite-bearing hornfels adjacent to the quartz monzonite stocks. The chemical changes in chlorite, biotite, garnet, cordierite, and muscovite in the chlorite, biotite, andalusite, and sillimanite zones have been-studied by optical and x-ray methods and by partial chemical analyses. The progressive changes in mineral assemblages have been graphically portrayed on quaternary diagrams and ternary projections.

Open-File Report↗
USGS2001

Sea-level and environmental changes since the last interglacial in the Gulf of Carpentaria, Australia: an overview

The Gulf of Carpentaria is an epicontinental sea (maximum depth 70 m) between Australia and New Guinea, bordered to the east by Torres Strait (currently 12 m deep) and to the west by the Arafura Sill (53 m below present sea level). Throughout the Quaternary, during times of low sea-level, the Gulf was separated from the open waters of the Indian and Pacific Oceans, forming Lake Carpentaria, an isolation basin, perched above contemporaneous sea-level with outlet channels to the Arafura Sea. A preliminary interpretation is presented of the palaeoenvironments recorded in six sediment cores collected by the IMAGES program in the Gulf of Carpentaria. The longest core (approx. 15 m) spans the past 130 ka and includes a record of sea-level/lake-level changes, with particular complexity between 80 and 40 ka when sea-level repeatedly breached and withdrew from Gulf/Lake Carpentaria. Evidence from biotic remains (foraminifers, ostracods, pollen), sedimentology and geochemistry clearly identifies a final marine transgression at about 9.7 ka (radiocarbon years). Before this transgression, Lake Carpentaria was surrounded by grassland, was near full, and may have had a surface area approaching 600 km×300 km and a depth of about 15 m. The earlier rise in sea-level which accompanied the Marine Isotopic Stage 6/5 transgression at about 130 ka is constrained by sedimentological and biotic evidence and dated by optical- and thermoluminescence and amino acid racemisation methods.

Gulf Of Carpentaria↗
USGS1981

Altitude and configuration of the water table in the High Plains aquifer in Kansas, 1980

The High Plains aquifer in Kansas is part of a regional system that extends into Colorado, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. The aquifer in Kansas underlies an area of 31,000 square miles in the western and south-central part of the State. This aquifer is a hydraulically connected assemblage of unconsolidated water-bearing deposits. In western Kansas, the High Plains aquifer consists principally of the Ogallala Formation of late Tertiary age and the overlying deposits of Quaternary age. In south-central Kansas, the aquifer consists of unconsolidated deposits principally of the Quaternary age. Valley alluvium of Quaternary age also is included in the deposits in both areas. The High Plains aquifer is delimited on the east by outcrops of Permian or Cretaceous rocks and by unsaturated deposits of Quaternary age.

Kansas↗
USGS1984

Reconnaissance geologic map of the Janban Quadrangle, sheet 20/44 B, Kingdom of Saudi Arabia

The Janban quadrangle, 20/44B, lies along the eastern margin of the Arabian Shield. The oldest rocks comprise the Precambrian Namtah Formation of the Halaban(?) group, and consist of basalt, dacite, siltstone, and calcareous greywacke metamorphosed in the lower amphibolite facies. Metamorphic rocks of uncertain Precambrian age in the northern part of the quadrangle are amphibolite, gneissic quartz diorite and metarhyolite that occur as roof pendants in plutonic rocks. Precambrian intrusive rocks, in order of decreasing age, are: biotite-hornblende tonalite; the locally gneissic Dawasir granodiorite and granite; the as Sabahah granite, coarse-grained alkaline granite; biotite-muscovite granite forming a small circular stock; the Janban granite, a coarse-grained non-foliated alkali-feldspar rapakiyl granite; aplitic granite; and fine-grained alkali granite that forms a stock, plugs, and dikes. Andesite dikes cut most of the plutonic rock units. Precambrian rocks are unconformably overlain by the Wajid Sandstone of Cambrian and Ordovician age, which covers the southeastern half of the quadrangle and consists of reddish-brown, medium-grained arkosic sandstone. Tertiary lake beds of gray marl, siltstone, and sandstone crop out locally, and lie unconformably on the Wajid. Most of the Wajid sandstone is mantled by an extensive blanket of Quaternary eolian sand and silt.

Open-File Report↗
USGS2007

Map and data for Quaternary faults and fault systems on the Island of Hawai'i

Introduction This report and digitally prepared, GIS-based map is one of a series of similar products covering individual states or regions of United States that show the locations, ages, and activity rates of major earthquake-related features such as faults and fault-related folds. It is part of a continuing the effort to compile a comprehensive Quaternary fault and fold map and database for the United States, which is supported by the U.S. Geological Survey's (USGS) Earthquake Hazards Program. Guidelines for the compilation of the Quaternary fault and fold maps for the United States were published by Haller and others (1993) at the onset of this project. This compilation of Quaternary surface faulting and folding in Hawai`i is one of several similar state and regional compilations that were planned for the United States. Reports published to date include West Texas (Collins and others, 1996), New Mexico (Machette and others, 1998), Arizona (Pearthree, 1998), Colorado (Widmann and others, 1998), Montana (Stickney and others, 2000), Idaho (Haller and others, 2005), and Washington (Lidke and others, 2003). Reports for other states such as California and Alaska are still in preparation. The primary intention of this compilation is to aid in seismic-hazard evaluations. The report contains detailed information on the location and style of faulting, the time of most recent movement, and assigns each feature to a slip-rate category (as a proxy for fault activity). It also contains the name and affiliation of the compiler, date of compilation, geographic and other paleoseismologic parameters, as well as an extensive set of references for each feature. The map (plate 1) shows faults, volcanic rift zones, and lineaments that show evidence of Quaternary surface movement related to faulting, including data on the time of most recent movement, sense of movement, slip rate, and continuity of surface expression. This compilation is presented as a digitally prepared map product and catalog of data, both in Adobe Acrobat PDF format. The senior authors (Eric C. Cannon and Roland Burgmann) compiled the fault data as part of ongoing studies of active faulting on the Island of Hawai`i. The USGS is responsible for organizing and integrating the State or regional products under their National Seismic Hazard Mapping project, including the coordination and oversight of contributions from individuals and groups (Michael N. Machette and Anthony J. Crone), database design and management (Kathleen M. Haller), and digitization and analysis of map data (Richard L. Dart). After being released an Open-File Report, the data in this report will be available online at http://earthquake.usgs.gov/regional/qfaults/, the USGS Quaternary Fault and Fold Database of the United States.

Hawaii↗