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USGS2003

Map of surficial deposits and materials in the eastern and central United States (east of 102 degrees West longitude)

This data set contains surficial geologic units in the Eastern and Central United States, as well as a glacial limit line showing the position of maximum glacial advance during various geologic time periods. The geologic units represent surficial deposits and other surface materials that accumulated or formed during the past 2+ million years, such as soils, alluvium, and glacial deposits. These surface materials are referred to collectively by many geologists as regolith, the mantle of fragmented and generally unconsolidated material that overlies the bedrock foundation of a continent. This data set and the printed map produced from it, U.S. Geological Survey (USGS) Geologic Investigation Series I-2789, were based on 31 published maps in the USGS's Quaternary Geologic Atlas of the United States map series (USGS Miscellaneous Investigations Series I-1420). The data were compiled at 1:1,000,000 scale, to be viewed as a digital map at 1:2,000,000 nominal scale and to be printed as a conventional paper map at 1:2,500,000 scale.

IMAP↗

USGS1946

The quartz crystal deposits of western Arkansas

Extensive geological investigations of domestic deposits of quartz crystals were undertaken by the Geological Survey of the United States Department of the Interior in the fall of 1942 in response to the urgent demand for crystals for war purposes. The work was continued throughout 1943 and took survey geologists into some 20 states in which over 1,400 deposits or reports of deposits were examined. Of the numerous highly varied occurrences of quartz examined, only the deposits in western Arkansas, in the Piedmont and Blue Ridge provinces of Virginia, North Carolina and Georgia and the placer quartz of Mokelumne Hill, California, were of sufficient promise to warrant detailed work. Production in 1943 from these areas totaled slightly less than 4 tons of oscillator quartz, over 85 per cent of which came from Arkansas.The Arkansas deposits occur throughout the thick, deformed Paleozoic shales, sandstones, and cherts exposed along the central belt of the Ouachita Mountains. Steeply dipping fractures closely related to the major folds control the deposition of most quartz.Clear quartz is confined largely to the terminal parts of primary crystals, which have developed without disturbance or interference, are commonly elongate parallel to their C axes and are bounded by relatively simple forms. Deposition of silica during and subsequent to the fracturing of crystals resulted in the formation of complex crystals which are characterized by extensive optical twinning and lineage structures, and commonly are bounded by aggregates of the simpler crystal forms. The principal defects in all types of crystals are twinning, smokiness, cavities, solid inclusions and fractures.The Arkansas quartz deposits include veins, sheeted zones and stock-works. They are largely cavity fillings, apparently deposited by rising, attenuated, hydrothermal solutions, at relatively low temperatures and pressures. Minerals associated with the quartz, which constitutes 90 per cent or more of the cavity fillings, include dickite and carbonaceous material, calcite, adularia, and chlorite. The constituents of the cavity fillings could have been derived principally from magmatic sources or more probably from underlying rocks, with small additions from the rocks enclosing the cavities. The complex vein fabrics apparently resulting from intermittent regional deformation during the deposition of the quartz, and certain structural relations of the deposits, indicate that they were formed in the final stages of the Ouachita orogeny, probably in mid-Pennsylvanian time.

Arkansas↗

USGS1982

A plan for hydrologic investigations of in situ, oil-shale retorting near Rock Springs, Wyoming

The recovery of shale oil by the in-situ retort process may cause hydrologic impacts, the most significant being ground-water contamination and possible transport of contaminants into surrounding areas. Although these impacts are site-specific, many of the techniques used to investigate each retort operation commonly will be the same. The U.S. Geological Survey has begun a study of hydrologic impacts in the area of an in-situ retort near Rock Springs, Wyoming, as a means of refining and demonstrating these techniques. Geological investigations include determining the areal extent and thickness of aquifers. Emphasis will be placed on determining lithologic variations from geophysical logging. Hydrologic investigations include mapping of potentiometric surfaces, determining rates of ground-water discharge, and estimating aquifer properties by analytical techniques. Water-quality investigations include monitoring solute migration from the retort site and evaluating sampling techniques by standard statistical procedures. A ground-water-flow and solute-transport model will be developed to predict future movement of the water plume away from the retort. (USGS)

Open-File Report↗

USGS1984

Measured Sections of Upper Paleozoic to Early Tertiary Rocks, Demarcation Point Quadrangle, Alaska

Introduction Twelve sections of upper Paleozoic to early Tertiary rocks from the Demarcation Point quadrangle and the northern edge of the Table Mountain quadrangle are presented. These measured sections include the type sections for the Joe Creek Member of the Echooka Formation (Section 11), the Bathtub Graywacke and Kongakut Formation (Section 9), and the unnamed early Tertiary rocks (Section 1). The early Tertiary rocks correlate closely with the Moose Channel Formation in the MacKenzie Delta, Candada (Detterman and Spicer, 1981). The sections were measured with a Jacob's staff during the geologic investigations of the Demarcation Point quadrangle in 1969 to 1971. The geologic map is published in generalized form (Detterman, 1974, 1976; Detterman and others, 1975). The sections are at a scale of 1 in to 100 ft, except for section 1, which is at 1 in to 200 ft. The location map shows the year and station number for each station. Fossils collected from these rocks and marked by and asterisk (*) are included in Detterman and others, 1975 (p. 42-45). A double asterisk (**) indicates they are included in the list below. All other fossil indicators mean fossils are present, but not collected.

Open-File Report↗

USGS1966

Gravity survey and regional geology of the Prince William Sound epicentral region, Alaska

Sedimentary and volcanic rocks of Mesozoic and early Tertiary age form a roughly arcuate pattern in and around Prince William Sound, the epicentral region of the Alaska earthquake of 1964. These rocks include the Valdez Group, a predominantly slate and graywacke sequence of Jurassic and Cretaceous age, and the Orca Group, a younger sequence of early Tertiary age. The Orca consists of a lower unit of dense-average 2.87 g per cm 3 (grams per cubic centimeter) pillow basalt and greenstone intercalated with sedimentary rocks and an upper unit of lithologically variable sandstone interbedded with siltstone or argillite. Densities of the clastic rocks in both the Valdez and Orca Groups average about 2.69 g per cm 3 . Granitic rocks of relatively low density (2.62 g per cm 3 ) cut the Valdez and Orca Groups at several localities. Both the Valdez and the Orca Groups were complexly folded and extensively faulted during at least three major episodes of deformation: an early period of Cretaceous or early Tertiary orogeny, a second orogeny that probably culminated in late Eocene or early Oligocene time and was accompanied or closely followed by emplacement of granitic batholiths, and a third episode of deformation that began in late Cenozoic time and continued intermittently to the present. About 500 gravity stations were established in the Prince William Sound region in conjunction with postearthquake geologic investigations. Simple Bouguer anomaly contours trend approximately parallel to the arcuate geologic structure around the sound. Bouguer anomalies decrease northward from +40 mgal (milligals) at the southwestern end of Montague Island to -70 mgal at College and Harriman Fiords. Most of this change may be interpreted as a regional gradient caused by thickening of the continental crust. Superimposed on the gradient is a prominent gravity high of as much as 65 mgal that extends from Elrington Island on the southwest, across Knight and Glacier Islands to the Ellamar Peninsula and Valdez on the northeast. This high coincides with the wide belt of greenstone and pillow basalt of the Orca Group and largely reflects the high density of these volcanic rocks. A large low in the east-central part of the sound is inferred to have a composite origin, and results from the combined effects of low-density sedimentary and granitic rocks. The Prince William Sound gravity high extends southwest-northeast without major horizontal offset for more than 100 miles. Thus the belt of volcanic rocks causing the high constitutes a major virtually continuous, geologic element of south-central Alaska.

Alaska↗

USGS2014

Geologic sources and concentrations of selenium in the West-Central Denver Basin, including the Toll Gate Creek watershed, Aurora, Colorado, 2003-2007

Toll Gate Creek, in the west-central part of the Denver Basin, is a perennial stream in which concentrations of dissolved selenium have consistently exceeded the Colorado aquatic-life standard of 4.6 micrograms per liter. Recent studies of selenium in Toll Gate Creek identified the Denver lignite zone of the non-marine Cretaceous to Tertiary-aged (Paleocene) Denver Formation underlying the watershed as the geologic source of dissolved selenium to shallow ground-water and surface water. Previous work led to this study by the U.S. Geological Survey, in cooperation with the City of Aurora Utilities Department, which investigated geologic sources of selenium and selenium concentrations in the watershed. This report documents the occurrence of selenium-bearing rocks and groundwater within the Cretaceous- to Tertiary-aged Denver Formation in the west-central part of the Denver Basin, including the Toll Gate Creek watershed. The report presents background information on geochemical processes controlling selenium concentrations in the aquatic environment and possible geologic sources of selenium; the hydrogeologic setting of the watershed; selenium results from groundwater-sampling programs; and chemical analyses of solids samples as evidence that weathering of the Denver Formation is a geologic source of selenium to groundwater and surface water in the west-central part of the Denver Basin, including Toll Gate Creek. Analyses of water samples collected from 61 water-table wells in 2003 and from 19 water-table wells in 2007 indicate dissolved selenium concentrations in groundwater in the west-central Denver Basin frequently exceeded the Colorado aquatic-life standard and in some locations exceeded the primary drinking-water standard of 50 micrograms per liter. The greatest selenium concentrations were associated with oxidized groundwater samples from wells completed in bedrock materials. Selenium analysis of geologic core samples indicates that total selenium concentrations were greatest in samples containing indications of reducing conditions and organic matter (dark gray to black claystones and lignite horizons). The Toll Gate Creek watershed is situated in a unique hydrogeologic setting in the west-central part of the Denver Basin such that weathering of Cretaceous- to Tertiary-aged, non-marine, selenium-bearing rocks releases selenium to groundwater and surface water under present-day semi-arid environmental conditions. The Denver Formation contains several known and suspected geologic sources of selenium including: (1) lignite deposits; (2) tonstein partings; (3) organic-rich bentonite claystones; (4) salts formed as secondary weathering products; and possibly (5) the Cretaceous-Tertiary boundary. Organically complexed selenium and/or selenium-bearing pyrite in the enclosing claystones are likely the primary mineral sources of selenium in the Denver Formation, and correlations between concentration of dissolved selenium and dissolved organic carbon in groundwater indicate weathering and dissolution of organically complexed selenium from organic-rich claystone is a primary process mobilizing selenium. Secondary salts accumulated along fractures and bedding planes in the weathered zone are another potential geologic source of selenium, although their composition was not specifically addressed by the solids analyses. Results from this and previous work indicate that shallow groundwater and streams similarly positioned over Denver Formation claystone units at other locations in the Denver Basin also may contain concentrations of dissolved selenium greater than the Colorado aquatic-life standard or the drinking- water standard.

Colorado↗

USGS2002

Geologic Map of the Katmai Volcanic Cluster, Katmai National Park, Alaska

This digital publication contains all the geologic map information used to publish U.S. Geological Survey Geologic Investigations Map Series I-2778 (Hildreth and Fierstein, 2003). This is a geologic map of the Katmai volcanic cluster on the Alaska Peninsula (including Mount Katmai, Trident Volcano, Mount Mageik, Mount Martin, Mount Griggs, Snowy Mountain, Alagogshak volcano, and Novarupta volcano), and shows the distribution of ejecta from the great eruption of June, 1912 at Novarupta. Widely scattered erosional remnants of volcanic rocks, unrelated to but in the vicinity of the Katmai cluster, are also mapped. Distribution of glacial deposits, large landslides, debris avalanches, and surficial deposits are a snapshot of an ever-changing landscape.

IMAP↗

USGS1980

Geologic literature on Egypt, 1933 to 1978

The following list of references includes most of the geological literature on Egypt published between 1933 and 1978; a few entries have been added from years prior to or after this period. To insure complete coverage, some publications that refer to areas adjacent to or extending slightly beyond the political boundaries of Egypt have been included. Abstracts, theses, dissertations, and unpublished papers are not included. Entries in this index to the geological literature on Egypt are arranged by author and year and are cross-indexed under subject headings that are listed in alphabetical order. In the subject index, subheadings under Areal Studies provide for a rapid survey of literature pertaining to a particular geographic area. Geographic boundaries are primarily those defined within the confines of the Egyptian Geological Survey's 1:500,000 base-map sheets (see figure 1). This compilation has been made as part of a program of geological investigations of the energy resources of Egypt conducted cooperatively by the U.S. Geological Survey and the Geological Survey of Egypt for the Government of Egypt and the U.S. Department of Energy. The compilers wish to acknowledge special assistance rendered by Jacquelyn H. Freeberg and William G. Sanders of the Geological Survey in locating little-known references and publications.

Open-File Report↗

USGS1955

Geology of the southeastern part of the Robinson Mountains, Yakataga district, Alaska

This report gives the results of geologic investigations in the Yakataga district on the south coast of Alaska, including detailed geologic mapping in the southeastern part of the Robinson Mountains, and reconnaissance study of the stratigraphy and structure of adjoining areas. The geologic map that accompanies this report covers an area of 630 square miles and includes the Bering Glacier (A-2), (A-3), and (A-4) quadrangles and the Icy Bay (D-2 and D-3) quadrangle of the Alaska inch-to-the-mile quadrangle map series. (see fig,. 1.)

Alaska↗

USGS1974

Geology of the San Francisco North quadrangle, California

San Francisco is a heavily built up city in a region of active faults and is subject to earthquakes and landslides. In such an area careful selection of building sites and foundations is imperative. This geologic investigation of the San Francisco North quadrangle was carried out to obtain basic geologic data to aid in construction and other civil engineering problems. The study also contributes to a better understanding of the geology of this part of the Coast Ranges in general and of the Franciscan Formation and surficial deposits in particular. On the geologic map (pl. 1) , consolidated rocks are delineated by their composition, age, and origin. Such a classification also gives an approximate indication of the engineering properties of each formation. To make the map more useful to the civil engineer, unconsolidated deposits are shown where thick enough to be depicted. This report and the accompanying map should be a useful guide for planning foundation studies necessary in engineering design.

California↗

USGS1964

Preliminary report on the geologic and geophysical investigations of the Loveland Basin landslide, Clear Creek County, Colorado

Geologic and geophysical investigations of the Loveland Basin landslide, which formed at the cut for the east portal of the Straight Creek tunnel, were made by the U.S. Geological Survey in cooperation with the U.S. Bureau of Public Road and the Colorado Department of Highways. The investigations indicate that the slide has a probable minimum volume of 500,000 cubic yards weighing 1,000,000 tons and probable maximum volume of 770,000 cubic yards weighing 1,600,000 tons.

Colorado↗

USGS2006

Reconnaissance investigation of Caribbean extreme wave deposits — Preliminary observations, interpretations, and research directions

This report presents an overview of preliminary geological investigations and recommended future research activities in the Caribbean region pertaining to coastal hazards with an emphasis on establishing tsunami risk for U.S. territories. Fieldwork was conducted in March 2006 on the islands of Bonaire, Puerto Rico, and Guadeloupe to evaluate the stratigraphic records of extreme wave deposits as possible indicators of paleotsunami recurrence. Morphological, sedimentological, and stratigraphic evidence indicate that shore-parallel coral rubble deposits composed of coarse clasts and sand that are 10s of meters wide and several meters thick are depositional complexes that have accumulated for a few centuries or millennia, and are not entirely the result of one or a few tsunamis as previously reported. The origins of boulder fields on elevated rock platforms of the Caribbean islands are more complicated than the origins of ridge complexes because boulder fields can be constructed by either storm waves or tsunamis. What is needed now for more conclusive interpretations is a systematic sedimentological approach to deposit analysis and a set of criteria for distinguishing between coarse clast storm and tsunami deposits. Assembling more field data from other Caribbean islands, analyzing stratigraphic deposits on Puerto Rico and Bonaire, and investigating boulder field deposits resulting from a historical tsunami can accomplish this. Also needed are improved sediment transport models for coarse clasts that can be used to estimate the competence and capacity of tsunamis and storms waves and to determine whether a deposit likely was created by a tsunami or extreme storm. Improved models may also be useful for reconstructing the magnitude of extreme wave events.

Puerto Rico↗

USGS1997

Geologic studies in Alaska by the U.S. Geological Survey, 1995

This collection of 20 papers continues the annual series of U.S. Geological Survey (USGS) reports on geologic investigations in Alaska1 . Contributions cover a broad spectrum of earth science topics and report results from all parts of the State (fig. 1). USGS activities in Alaska include studies of environment and climate, hazards, resources, and geologic framework. Five papers in this volume discuss aspects of environment and climate. Environmental geochemistry of parts of southwestern and south-central Alaska is the focus of four articles; a fifth study, of emergent postglacial lake shorelines in southwestern Alaska, contributes to ongoing investigations of paleoclimate. Two papers address geologic hazards. The first assesses ground deformation in Katmai National Park at Novarupta dome, site of the largest volcanic eruption in this century, and the second evaluates earthquake risks related to the "Twin Peak fault" near Anchorage. Resources, including metallic minerals in northern, southwestern, and southeastern Alaska and coal in south-central Alaska, are discussed in four articles. Nine geologic framework studies apply a variety of techniques to a wide range of subjects throughout Alaska, including tectonics, geophysics, geochronology, bio stratigraphy, sedimentology, paleogeography, and paleomagnetism. Two bibliographies at the end of the volume list reports about Alaska in USGS publications released in 1995 and reports about Alaska by USGS authors in non-USGS publications in 1995.

Alaska↗

USGS2008

Site characterization of Italian strong motion recording stations

A dataset of site conditions at 101 Italian ground motion stations with recorded motions has been compiled that includes geologic characteristics and seismic velocities. Geologic characterization is derived principally from local geologic investigations by ENEL that include detailed mapping and cross sections. For sites lacking such detailed geologic characterization, the geology maps of the by Servizio Geologico d'Italia are used. Seismic velocities are extracted from the literature and the files of consulting engineers, geologists and public agencies for 33 sites. Data sources utilized include post earthquake site investigations (Friuli and Irpinia events), microzonation studies, and miscellaneous investigations performed by researchers or consulting engineers/geologists. Additional seismic velocities are measured by the authors using the controlled source spectral analysis of surface waves (SASW) method for 18 sites that recorded the 1997–1998 Umbria Marche earthquake sequence. The compiled velocity measurements provide data for 51 of the 101 sites. For the remaining sites, the average seismic velocity in the upper 30 m (V s30 ) "> (V s30 ) is estimated using a hybrid approach. For young Quaternary alluvium, V s30 "> 𝑉 s30 an existing empirical relationship for California sites by Wills and Clahan (2006) is used, which we justify by validating this relationship against Italian data. For Tertiary Limestone and Italian Mesozoic rocks, empirical estimates of V s30 "> 𝑉 s30 are developed using the available data.

Conference Paper↗

USGS1992

Geologic studies in Alaska by the U.S. Geological Survey, 1990

This collection of papers continues the annual series of U.S. Geological Survey (USGS) reports on geologic investigations in Alaska. From 1975 through 1988, the series was published as USGS circulars. The first of these appeared under the title "The United States Geological Survey in Alaska: Accomplishments during 1975," and the series continued to the last annual circular entitled "Geologic studies in Alaska by the U.S. Geological Survey during 1987," which reflects a title change made in 1986. This 1990 volume continues the bulletin format started in 1988. As in 1989, this volume separates shorter contributions as Geologic Notes from more extensive Articles. This 1990 volume of 18 Articles and 4 Geologic Notes represents the broad range of USGS research activities carried out in Alaska over the past few years. These studies include topics on mineral and other resources such as gold (Y eend), platinum-group elements (Cathrall and Antweiler), coal (Roberts, Stricker, and Affolter), and petroleum (Howell, Bird, and others). Many other investigations provide background geochemical (Kilburn, Box, and others) and geologic data needed for resource evaluation as well as for determining the general geologic framework of Alaska, as in stratigraphic, sedimentologic, and paleontologic and radiometric age studies (Blodgett, Clough, and others; Box and Elder; Dickinson and Skipp; Marincovich and Moriya; McLean and Stanley; Stanley, Flores, and Wiley; Roeske, Pavlis, and others); geophysics (Sampson, Labson, and Long); structure and tectonic evaluations (Bradley and Kosky; Clendenen, Sliter, and Byrne; Karl; Csejtey; Howell, Johnsson, and others); and geomorphic and late Quaternary studies (Carter and Hillhouse; Galloway, Huebner, and others; McGimsey, Richter, and others; Nelson and Carter). These studies span nearly the entire State from the North Slope and Brooks Range to interior, southwestern, and south-central Alaska (fig. 1). Two bibliographies (White) at the end of the volume list (1) reports about Alaska in USGS publications released in 1990 and (2) reports about Alaska by USGS authors in publications outside the USGS in 1990. A bibliography and index of papers in past USGS circulars that are devoted to geologic research and accomplishments in Alaska (1975 to 1986) is published as USGS Open-File Report 87-420.

Alaska↗

USGS1955

Preliminary geologic evaluation of the Chena area, Alaska

It seems fitting at this session of the Alaska Science Conference, the first to be held in the Fairbanks area, to give a preliminary summary of the practical results of a geologic investigation of the Chena area east of Fairbanks. The work was done by the Geological Survey in 1950. One important objective of the study was to consider some of the geologic problems affecting development of the land for commercial and agricultural use -- especially to outline the parts of the area that are subject to possible ground subsidence and differential settling because of melting of ground ice masses in permafrost following clearing of the land for agriculture and for construction.

Alaska↗

USGS1997

Digital geologic map database of the Nevada Test Site area, Nevada

Forty years of geologic investigations at the Nevada Test Site (NTS) have been digitized. These data include all geologic information that: (1) has been collected, and (2) can be represented on a map within the map borders at the map scale is included in the map digital coverages. The following coverages are included with this dataset: Coverage Type Description geolpoly Polygon Geologic outcrops geolflts line Fault traces geolatts Point Bedding attitudes, etc. geolcald line Caldera boundaries geollins line Interpreted lineaments geolmeta line Metamorphic gradients The above coverages are attributed with numeric values and interpreted information. The entity files documented below show the data associated with each coverage.

Nevada↗

USGS1970

Analyses of stream-sediment samples from western St. Lawrence Island, Alaska

Analytical data for 207 stream-sediment samples from western St. Lawrence Island are presented in this report, together with a statistical treatment of the data. The samples were collected in 1968 and 1969 as part of the Heavy Metals Program of the U.S. Geological Survey. This report is intended to supplement Geological Survey open-file report entitled "Preliminary geologic investigations of western St. Lawrence Island, Alaska" (Patton and Csejtey, 1970) which describes the general geology of the area and discusses several localities where anomalous amounts of metals were found.

Alaska↗