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At least 253 records · Page 14Linked to original sources
USGS2015

Ignimbrites to batholiths: integrating perspectives from geological, geophysical, and geochronological data

Multistage histories of incremental accumulation, fractionation, and solidification during construction of large subvolcanic magma bodies that remained sufficiently liquid to erupt are recorded by Tertiary ignimbrites, source calderas, and granitoid intrusions associated with large gravity lows at the Southern Rocky Mountain volcanic field (SRMVF). Geophysical data combined with geological constraints and comparisons with tilted plutons and magmatic-arc sections elsewhere are consistent with the presence of vertically extensive (>20 km) intermediate to silicic batholiths (with intrusive:extrusive ratios of 10:1 or greater) beneath the major SRMVF volcanic loci (Sawatch, San Juan, Questa-Latir). Isotopic data require involvement of voluminous mantle-derived mafic magmas on a scale equal to or greater than that of the intermediate to silicic volcanic and plutonic rocks. Early waxing-stage intrusions (35–30 Ma) that fed intermediate-composition central volcanoes of the San Juan locus are more widespread than the geophysically defined batholith; these likely heated and processed the crust, preparatory for ignimbrite volcanism (32–27 Ma) and large-scale upper-crustal batholith growth. Age and compositional similarities indicate that SRMVF ignimbrites and granitic intrusions are closely related, but the extent to which the plutons record remnants of former magma reservoirs that lost melt to volcanic eruptions has been controversial. Published Ar/Ar-feldspar and U-Pb-zircon ages for plutons spatially associated with ignimbrite calderas document final crystallization of granitoid intrusions at times indistinguishable from the tuff to ages several million years younger. These ages also show that SRMVF caldera-related intrusions cooled and solidified soon after zircon crystallization, as magma supply waned. Some researchers interpret these results as recording pluton assembly in small increments that crystallized rapidly, leading to temporal disconnects between ignimbrite eruption and intrusion growth. Alternatively, crystallization ages of the granitic rocks are here inferred to record late solidification, after protracted open-system evolution involving voluminous mantle input, lengthy residence (10 5 –10 6 yr) as near-solidus crystal mush, and intermittent separation of liquid to supply volcanic eruptions. The compositions of the least-evolved ignimbrite magmas tend to merge with those of caldera-related plutons, suggesting that the plutons record nonerupted parts of long-lived cogenetic magmatic systems, variably modified prior to final solidification. Precambrian-source zircons are scarce in caldera plutons, in contrast to their abundance in some peripheral waning-stage intrusions of the SRMVF, implying dissolution of inherited crustal zircon during lengthy magma assembly for the ignimbrite eruptions and construction of a subvolcanic batholith. Broad age spans of zircons (to several million years) from individual samples of some ignimbrites and intrusions, commonly averaged and interpreted as “intrusion-emplacement age,” alternatively provide an incomplete record of intermittent crystallization during protracted incremental magma-body assembly, with final solidification only when the system began to wane. Analyses of whole zircons cannot resolve late stages of crystal growth, and early growth in a long-lived magmatic system may be poorly recorded due to periods of zircon dissolution. Overall, construction of a batholith can take longer than recorded by zircon-crystallization ages, while the time interval for separation and shallow assembly of eruptible magma may be much shorter. Magma-supply estimates (from ages and volcano-plutonic volumes) yield focused intrusion-assembly rates sufficient to generate ignimbrite-scale volumes of eruptible magma, based on published thermal models. Mid-Tertiary processes of batholith assembly associated with the SRMVF caused drastic chemical and physical reconstruction of the entire lithosphere, probably accompanied by asthenospheric input.

Colorado, New Mexico↗
USGS2017

Geophysical expression of buried range-front embayment structure: Great Sand Dunes National Park, Rio Grande rift, Colorado

Great Sand Dunes National Park and Preserve (GRSA, Colorado) lies along the eastern margin of the San Luis Basin and the tectonically active Sangre de Cristo fault system that are part of the northern Rio Grande rift. GRSA lies within a prominent embayment in the range front where two separate sections of the Sangre de Cristo fault system intersect. Fault scarps are observed along both intersecting fault zones within older basin-fill alluvium, but have been obscured by the actively migrating dunefield. The dune sand is also strongly magnetic, locally limiting the usefulness of aeromagnetic methods for mapping concealed structure. This study uses airborne geophysical methods, primarily airborne gravity gradient data, along with constraints from geologic mapping and limited subsurface data and groundwater modeling, to interpret the subsurface basin geometry and range-front structure of the embayment. Using forward modeling of the gravity gradient data and locations of faults inferred from gravity gradient and aeromagnetic lineaments, several previously unrecognized tectonic elements are interpreted adjacent to the range front. Some of the largest rift-related fault offsets are demonstrated to be basinward of the normal fault zones mapped at the surface along the range front of the Sangre de Cristo Mountains, along faults concealed under the dunefield and subparallel to the two fault sections. A fault-bounded structural bench, likely composed of Proterozoic rocks, underlies most of the high dunefield at depths of 500 m to 1 km. The bench is truncated on its southwest margin by a northwest-trending, southwest-dipping normal fault. A northeast-trending, northwest-dipping normal fault with ∼600 m of estimated relief lies under the southern margin of the dunefield and bounds a structurally higher bench of Proterozoic rocks concealed at <400 m depth near the range front. The northwest- and northeast-trending geophysical lineaments generally correspond well with the trends of faults mapped at the surface, and with both pre- and syn-rift structures in the Sangre de Cristo Mountains. Aeromagnetic anomalies are explained by variations in the magnetization of pre-rift rocks, and the strongly magnetic dune sand.

Colorado↗
USGS2019

Geophysical characterization of a Proterozoic REE terrane at Mountain Pass, eastern Mojave Desert, California

Mountain Pass, California (USA), located in the eastern Mojave Desert, hosts one of the world’s richest rare earth element (REE) deposits. The REE-rich terrane occurs in a 2.5-km-wide, northwest-trending belt of Mesoproterozoic (1.4 Ga) stocks and dikes, which intrude a larger Paleoproterozoic (1.7 Ga) metamorphic block that extends ∼10 km southward from Clark Mountain to the eastern Mescal Range. To characterize the REE terrane, gravity, magnetic, magnetotelluric, and whole-rock physical property data were analyzed. Geophysical data reveal that the Mountain Pass carbonatite body is associated with an ∼5 mGal local gravity high that is superimposed on a gravity terrace (∼4 km wide) caused by granitic Paleoproterozoic host rocks. Physical rock property data indicate that the Mountain Pass REE suite is essentially nonmagnetic at the surface with a magnetic susceptibility of 2.0 × 10 −3 SI ( n = 57), and lower-than-expected magnetizations may be the result of alteration. However, aeromagnetic data indicate that the intrusive suite occurs along the eastern edge of a distinct northwest-trending aeromagnetic high along the eastern Mescal Range. The source of this magnetic anomaly is ∼1.5–2 km below the surface and coincides with an electrical conductivity zone that is several orders of magnitude more conductive than the surrounding rock. The source of the magnetic anomaly is likely a moderately magnetic pluton. Combined geophysical data and models suggest that the carbonatite and its associated REE-enriched ultrapotassic suite were preferentially emplaced along a northwest-trending zone of weakness, which has potential implications for regional mineral exploration.

California↗
USGS2015

What lies beneath: geophysical mapping of a concealed Precambrian intrusive complex along the Iowa–Minnesota border

Large-amplitude gravity and magnetic highs over northeast Iowa are interpreted to reflect a buried intrusive complex composed of mafic–ultramafic rocks, the northeast Iowa intrusive complex (NEIIC), intruding Yavapai province (1.8–1.72 Ga) rocks. The age of the complex is unproven, although it has been considered to be Keweenawan (∼1.1 Ga). Because only four boreholes reach the complex, which is covered by 200–700 m of Paleozoic sedimentary rocks, geophysical methods are critical to developing a better understanding of the nature and mineral resource potential of the NEIIC. Lithologic and cross-cutting relations interpreted from high-resolution aeromagnetic and airborne gravity gradient data are presented in the form of a preliminary geologic map of the basement Precambrian rocks. Numerous magnetic anomalies are coincident with airborne gravity gradient (AGG) highs, indicating widespread strongly magnetized and dense rocks of likely mafic–ultramafic composition. A Yavapai-age metagabbro unit is interpreted to be part of a layered intrusion with subvertical dip. Another presumed Yavapai unit has low density and weak magnetization, observations consistent with felsic plutons. Northeast-trending, linear magnetic lows are interpreted to reflect reversely magnetized diabase dikes and have properties consistent with Keweenawan rocks. The interpreted dikes are cut in places by normally magnetized mafic–ultramafic rocks, suggesting that the latter represent younger Keweenawan rocks. Distinctive horseshoe-shaped magnetic and AGG highs correspond with a known gabbro, and surround rocks with weaker magnetization and lower density. Here, informally called the Decorah complex, the source body has notable geophysical similarities to Keweenawan alkaline ring complexes, such as the Coldwell and Killala Lake complexes, and Mesoproterozoic anorogenic complexes, such as the Kiglapait, Hettasch, and Voisey’s Bay intrusions in Labrador. Results presented here suggest that much of the NEIIC is composed of such complexes, and broadly speaking, may be a discontinuous group of several intrusive bodies. Most units are cut by suspected northwest-trending faults imaged as magnetic lineaments, and one produces apparent sinistral fault separation of a dike in the eastern part of the survey area. The location, trend, and apparent sinistral sense of motion are consistent with the suspected faults being part of the Belle Plaine fault zone, a complex transform fault zone within the Midcontinent rift system that is here proposed to correspond with a major structural discontinuity.

Iowa, Minnesota↗
USGS1999

Deformation and quaternary faulting in southeast Missouri across the Commerce geophysical lineament

High-resolution seismic-reflection data acquired at three sites along the surface projection of the Commerce geophysical lineament in southeast Missouri reveal a complex history of post-Cretaceous faulting that has continued into the Quaternary. Near Qulin, Missouri, approximately 20 m of apparent vertical fault displacement has occurred in the Quaternary. Reflection data collected at Idalia Hill, about 45 km to the northeast, reveal a series of reverse and possibly right-lateral strike-slip faults with Quaternary displacement. In the Benton Hills, 45 km northeast of Idalia Hill, seismic data image a complicated series of anticlinal and synclinal fault-bounded blocks immediately north of the Commerce fault. We infer that most of the deformation imaged in the upper 400 m of these three data sets occurred since post-Cretaceous time, and a significant portion of it occurred during Quaternary time. Collectively, these seismic data along with geomorphic and surface-geologic evidence suggest (1) the existence of at least one potential seismogenic structure in southeastern Missouri outside the main zones of New Madrid seismicity, and (2) these structures have been active during the Quaternary. The geographic location of the imaged deformation suggests it is related to structures along with the Commerce geophysical lineament.

Missouri↗
USGS2002

The Commerce geophysical lineament and its possible relation to Mesoproterozoic igneous complexes and large earthquakes in the central Illinois Basin

New inversions of existing magnetic and gravity data lead to insights on upper crustal structures in the central Illinois basin. The results of 2D and 3D inversion techniques suggest that the source of the Commerce geophysical lineament follows the southeast boundary of a dense and magnetic, northeast-trending igneous center, named the Vincennes igneous center. Thus the Commerce geophysical lineament, defining the 5- to 10-km-wide Commerce deformation zone, appears to have influenced the structural development of the Vincennes igneous center. Overlying this igneous center is the Centralia seismic-reflection sequence, expressed as highly coherent reflectors ( McBride and Kolata, 1999 ). We suggest that the buried Vincennes igneous center is the source of inferred volcanic units of the Centralia sequence and is related to a rifted margin or a Proterozoic plate boundary. A comparison of gravity and magnetic fields over the Vincennes igneous center and the St. Francois Mountains igneous center in southeastern Missouri suggests that the associated sources in these regions are similar in composition and perhaps origin. Such a conclusion, although speculative, suggests that ∼1.47 Ga-year-old volcanic fields of high-silica rocks, with more abundant mafic components at depth, characterize basement in the regions of the Vincennes igneous center and the St. Francois Mountains. Further, we conclude that the Commerce deformation zone evolved in the Mesoproterozoic (1.1 to 1.5 Ga) as a major cratonic rheological boundary and was the focus of episodic reactivation related to varying stress regimes throughout its history. Spatial relations of the Commerce deformation zone with large Pleistocene and Holocene earthquakes suggest that the zone represents a major rheological boundary intimately related to both surface and deep structures and to the seismic hazard of the Illinois basin region. Assuming recent right-lateral slip along the Commerce deformation zone, we propose that a jog or left step in the Vincennes area leads to thrusting or a restraining bend, where associated stress accumulations may have resulted in nearby large prehistoric earthquakes and may also be the nucleation sites of future large earthquakes.

Illinois, Indiana, Kentucky↗
USGS1956

Geophysical abstracts 164, January-March 1956

Geophysical Abstracts includes abstracts of technical papers and books on the physics of the solid earth, the application of physical methods and techniques to geologic problems, and geophysical exploration. A new table of contents, alphabetically arranged, has been adapted to show more clearly the material covered. Abstracts are prepared only of material that is believed to be generally available. Ordinarily abstracts are not published of material with limited circulation (such as dissertations, open-file reports, or memoranda) or of papers presented orally at meetings unless summaries of substantial length are published. Abstracts of papers in Japanese and Chinese are based on abstracts or summaries in a western language accompanying the paper.

Bulletin↗
USGS1956

Geophysical abstracts 165, April-June 1956

Geophysical Abstracts includes abstracts of technical papers and books on the physics of the solid earth, the application of physical methods and techniques to geologic problems, and geophysical exploration. The table of contents, which is alphabetically arranged, shows the material covered. Abstracts are prepared only of material that is believed to be generally available. Ordinarily abstracts are not published of material with limited circulation (such as dissertations, open-file reports, or memoranda) or of other papers presented orally at meetings unless summaries of substantial length are published. Abstracts of papers in Japanese and Chinese are based on abstracts or summaries in a western language accompanying the paper.

Bulletin↗
USGS1956

Geophysical abstracts 166, July-September 1956

Geophysical Abstracts includes abstracts of technical papers and books on the physics of the solid earth, the application of physical methods and techniques to geologic problems, and geophysical exploration. The table of contents, which is alphabetically arranged, shows the material covered. Abstracts are prepared only of material that is believed to be generally available. Ordinarily abstracts are not published of material with limited circulation (such as dissertations, open-file reports, or memoranda) or of other papers presented orally at meetings unless summaries of substantial length are published. Abstracts of papers in Japanese and Chinese are based on abstracts or summaries in a western language accompanying the paper.

Bulletin↗
USGS1991

The Conterminous United States Mineral Appraisal Program; background information to accompany folio of geologic, geochemical, geophysical, and mineral resources maps of the Tonopah 1 by 2 degree Quadrangle, Nevada

The Tonopah 1 ? by 2 ? quadrangle in south-central Nevada was studied by an interdisciplinary research team to appraise its mineral resources. The appraisal is based on geological, geochemical, and geophysical field and laboratory investigations, the results of which are published as a folio of maps, figures, and tables, with accompanying discussions. This circular provides background information on the investigations and integrates the information presented in the folio. The selected bibliography lists references to the geology, geochemistry, geophysics, and mineral deposits of the Tonopah 1 ? by 2 ? quadrangle.

Circular↗
USGS1992

The Conterminous United States Mineral Assessment Project; background information to accompany folio of geologic, geochemical, geophysical, and mineral resources maps of the Reno 1 by 2 degree Quadrangle, Nevada and California

The Reno 1 ? by 2 ? quadrangle in west-central Nevada was studied by an interdisciplinary research team to appraise its mineral resources. The assessment is based on geological, geochemical, and geophysical field and laboratory investigations, the results of which are published as a folio of maps, reports, figures, and tables, with accompanying discussions. This circular provides background information on the investigations and integrates the information presented in the folio. The selected bibliography lists references to the geology, geochemistry, geophysics, and mineral deposits of the Reno 1 ? by 2 ? quadrangle.

Circular↗
USGS1992

The Conterminous United States Mineral Assessment Program: Background information to accompany folio of geologic, geochemical, geophysical, and mineral resource maps of the Ajo and Lukeville 1° by 2° quadrangles, Arizona

Encompassing about 21,000 km 2 in southwestern Arizona, the Ajo and Lukeville 1° by 2° quadrangles have been the subject of mineral resource investigations utilizing field and laboratory studies in the disciplines of geology, geochemistry, geophysics, and Landsat imagery. The results of these studies are published as a folio of maps, figures, and tables, with accompanying discussions. Past mineral production has been limited to copper from the Ajo Mining District. In addition to copper, the quadrangles contain potentially significant resources of gold and silver; a few other commodities, including molybdenum and evaporites, may also exist in the area as appreciable resources. This circular provides background information on the mineral deposits and on the investigations and integrates the information presented in the folio. The bibliography cites references to the geology, geochemistry, geophysics, and mineral deposits of the two quadrangles.

Arizona↗
USGS1986

The Conterminous United States Mineral Assessment Program; background information to accompany folio of geologic, geophysical, geochemical, mineral-occurrence, mineral-resource potential, and mineral-production maps of the Charlotte 1 degree x 2 degrees Quadrangle, North Carolina and South Carolina

This Circular and the folio of separately published maps described herein are part of a series of reports compiled under the Conterminous United States Mineral Assessment Program ICUSMAP). The folio on the Charlotte 1 degree ? 2 degree quadrangle, North Carolina and South Carolina, includes (1) a geologic map; (2) four geophysical maps; (3) geochemical maps for metamorphic heavy minerals, copper, lead and artifacts, zinc, gold, tin, beryllium, niobium, tungsten, molybdenum, titanium, cobalt, lithium, barium, antimony-arsenic-bismuth-cadmium, thorium-cerium-monazite, and limonite; (4) mineral-occurrence maps for kyanite-sillimanite-lithium-mica-feldspar-copper-lead-zinc, gold-quartz-barite-fluorite, iron-thorium-tin-niobium, and construction materials-gemstones; (5) mineral-resource potential maps for copper-lead-zinc-combined base metals, gold, tin-tungsten, beryllium-molybdenum-niobium, lithium-kyanite- sillimanitebarite, thorium (monazite)-uranium, and construction materials; and (6) mineral-production maps. The Charlotte quadrangle is mainly within the Piedmont physiographic province and extends from near the Coastal Plain on the southeast into the Blue Ridge province on the northwest for a short distance. Parts of six lithotectonic belts are present--the Blue Ridge, the Inner Piedmont, the Kings Mountain belt, the Charlotte belt, the Carolina slate belt, and the Wadesboro basin. Igneous, metamorphic, and sedimentary rocks are present and range in age from Proterozoic to Mesozoic; alluvial sediments of Quaternary age occur along rivers and larger streams. Rocks of the Blue Ridge include Middle Proterozoic granitoid gneiss intruded by Late Proterozoic granite; Late Proterozoic paragneiss, schist, and other metasedimentary and metavolcaniclastic rocks (Ashe and Grandfather Mountain Formations); Late Proterozoic and Early Cambrian metasedimentary rocks (Chilhowee Group); and Early Cambrian sedimentary rocks (Shady Dolomite). Paleozoic granites intrude the Proterozoic rocks. The Inner Piedmont contains noncarbonate metasedimentary rocks and amphibolite of medium to high metamorphic grades. These rocks are intruded by the Toluca Granite and Henderson Gneiss of Cambrian and Ordovician(?) age. The Charlotte belt consists largely of Late Proterozoic to Late Paleozoic granitic and gabbroic plutonic rocks and intervening enclaves of metasedimentary and metavolcanic rocks. The narrow Kings Mountain belt is located between the Charlotte and the Inner Piedmont belts and contains mainly Late Proterozoic metasedimentary rocks and plutonic rocks similar to those of the Charlotte belt. The Carolina slate belt, flanking the Charlotte belt on the east, contains weakly metamorphosed volcanic and sedimentary rocks. East of this belt, at the southeast corner of the quadrangle, is the Wadesboro basin, which has continental sedimentary rocks of Triassic age. Layered rocks westward from and in the Charlotte belt are complexly folded, are steeply dipping, and in the Blue Ridge and Inner Piedmont are contained within major thrust slices. Rocks of the Carolina slate belt are gently folded. Rocks of the Wadesboro basin occur in downfaulted blocks. The geophysical surveys of the Charlotte quadrangle consisted of Bouguer gravity, aeromagnetic, and aeroradioactivity surveys and used both newly obtained data and information from prior work. The gravity survey disclosed a distinct northeast-trending, northwest-decreasing gradient, which is part of the major gravity gradient that extends the length of the Appalachian Mountains. Granitic plutons of the Charlotte belt, in particular, are marked by gravity lows, and gabbro plutons, by highs. Several of the geologic belts display distinct magnetic character. The aeroradioactivity surveys showed a swath of consistently high gamma-ray intensities along the central part of the Inner Piedmont belt; these high intensities correspond to the so-called monazite belt. Oval patterns of high gamma-ray readi

Circular↗
USGS1986

The Conterminous United States Mineral Appraisal Program; background information to accompany folio of geologic, geochemical, geophysical, and mineral resources maps of the Medford 1 degree x 2 degrees Quadrangle, Oregon and California

The Medford 1 ? by 2 ? quadrangle in southern Oregon and northern California was studied by an interdisciplinary research team to appraise its mineral resources. The appraisal is based on geological, geochemical, and geophysical field and laboratory investigations, the results of which are published as a folio of maps, figures, and tables, with accompanying discussions. This circular provides background information on the investigations and integrates the information presented in the folio. The bibliography lists selected references to the geology, geochemistry, geophysics, and mineral deposits of the Medford 1 ? by 2 ? quadrangle.

Circular↗
USGS2017

Continued geophysical logging near the GMH Electronics National Priorities List Superfund site near Roxboro, North Carolina

The U.S. Geological Survey South Atlantic Water Science Center collected borehole geophysical logs and images and continuous water-level data near the GMH Electronics National Priorities List Superfund site near Roxboro, North Carolina, during December 2012 through July 2015. Previous work by the U.S. Geological Survey South Atlantic Water Science Center at the site involved the collection of borehole geophysical log data in 15 wells, in addition to surface geologic mapping and passive diffusion bag sampling. In a continued effort to assist the U.S. Environmental Protection Agency in developing a conceptual groundwater model to assess current contaminant distribution and future migration of contaminants, more than 900 subsurface features (primarily fracture orientations) in 10 open borehole wells were delineated and continuous water-level data information from 14 monitoring wells within close proximity of the initially drilled boreholes was collected to observe any induced water-level fluctuations during drilling operations

North Carolina↗
USGS2008

Construction diagrams, geophysical logs, and lithologic descriptions for boreholes USGS 126a, 126b, 127, 128, 129, 130, 131, 132, 133, and 134, Idaho National Laboratory, Idaho

This report summarizes construction, geophysical, and lithologic data collected from ten U.S. Geological Survey (USGS) boreholes completed between 1999 nd 2006 at the Idaho National Laboratory (INL): USGS 126a, 126b, 127, 128, 129, 130, 131, 132, 133, and 134. Nine boreholes were continuously cored; USGS 126b had 5 ft of core. Completion depths range from 472 to 1,238 ft. Geophysical data were collected for each borehole, and those data are summarized in this report. Cores were photographed and digitally logged using commercially available software. Digital core logs are in appendixes A through J. Borehole descriptions summarize location, completion date, and amount and type of core recovered. This report was prepared by the USGS in cooperation with the U.S. Department of Energy (DOE).

Idaho↗
USGS2009

Water-level, borehole geophysical log, and water-quality data from wells transecting the freshwater/saline-water interface of the San Antonio segment of the Edwards Aquifer, South-Central Texas, 1999-2007

As a part of a 9-year (1999-2007) study done by the U.S. Geological Survey in cooperation with the San Antonio Water System to improve understanding of the San Antonio segment of the Edwards aquifer, south-central Texas, in and near the freshwater/saline-water transition zone of the aquifer, the U.S. Geological Survey collected water-level, borehole geophysical, and water-quality data during 1999-2007 from 37 wells arranged in nine transects (except for two wells) across the freshwater/saline-water interface of the aquifer. This report presents the data collected and also describes the data-collection, analytical, and quality-assurance methods used. The wells, constructed with casing from land surface into the upper part of the aquifer and completed as open hole in the aquifer, are in Uvalde County (East Uvalde transect), in Medina County (South Medina and Devine wells), in Bexar County (Pitluk, Mission, and San Antonio transects), in Comal and Guadalupe Counties (Tri-County transect), in Comal County (New Braunfels transect), and in Hays County (Fish Hatchery, San Marcos, and Kyle transects). Data collected included continuous water level at 18 wells; fluid electrical conductivity and temperature with depth (fluid profiles) obtained by borehole geophysical logging of 15 wells; discrete (periodic) samples for major ions and trace elements at 36 wells; stable isotopes or stable isotopes and tritium at 27 wells; dissolved gases obtained by pumping (or collecting flow) of 19 wells; and continuous specific conductance and temperature at three of the wells equipped with continuous water-level sensors.

Data Series↗
USGS2010

Geophysical Logs of Selected Wells at the Diaz Chemical Superfund Site in the Village of Holley, New York, 2009

Geophysical logs were collected and analyzed to define the bedrock fracture patterns and flow zones penetrated by three wells at the Diaz Chemical Superfund Site in the Village of Holley in Orleans County, New York. The work was conducted in December 2009 as part of the investigation of contamination by organic compounds in the shale, mudstone, and sandstone bedrock at the Site. The geophysical logs include natural-gamma, caliper, borehole image, fluid properties, and flowmeter data. The orientation of fractures in the boreholes was inferred from the log data and summarized in stereo and tadpole plots; when possible, the transmissivity and hydraulic head was also determined for fracture zones that were observed to be hydraulically active through the flowmeter logs. The data are intended, in part, for use in the remediation of the site.

Data Series↗