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Twenty-two igneous and metamorphic rock samples were collected in a 20-km-long swath centered on the Alaska Highway between Tetlin Junction, Alaska, and the Canada border. Igneous and metamorphic rock samples were submitted to the Apatite to Zircon, Inc. laboratory (A2Z), where zircon U-Pb age analysis, using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), was performed by Paul O'Sullivan. The 15 felsic plutonic rock samples and one gabbro sample yield Cretaceous zircon U-Pb weighted-mean ages ranging from 95.7 Ma to 106.2 Ma. Zircons from a metadiorite yield a Triassic weighted-mean age of about 241.9 Ma. Metamorphic zircons from two samples with felsic igneous protoliths yield Mississippian...
Cook Inlet has been recognized as the second-largest petroleum province in Alaska, second only to the North Slope. The south-central Tyonek Quadrangle is an area of significant geologic interest because it is the only location in Cook Inlet where the entire producing stratigraphy of the basin is exposed on the surface. Additionally, this area encompasses the structural boundary between the forearc basin and its sediment source rocks. To better understand the petroleum system and the geologic relationships between the exhumed arc intrusive rocks and adjacent Cenozoic stratigraphy of the Cook Inlet forearc basin, during the summer of 2010 the Alaska Division of Geological & Geophysical Surveys conducted a federally-funded...
A physiographically prominent, approximately 40 square km plateau lies roughly 20 km east of Mount Spurr volcano, northwestern Cook Inlet region, Alaska, and comprises the preserved remnant of a volcaniclastic succession, designated in this study as map unit Qvc. Although this readily mappable package of volcaniclastic rocks has been recognized in numerous studies during the past five decades, uncertainties regarding its age and origin have persisted. We describe the general characteristics of the volcaniclastic plateau, provide new age constraints for deposits, present lithofacies descriptions and interpretations of the volcaniclastic strata, and synthesize our observations and lithofacies analysis to propose an...
The cold deserts of the Colorado Plateau contain numerous geologically and geochemically distinct sedimentary bedrock types. In the area near Canyonlands National Park in Southeastern Utah, geochemical variation in geologic substrates is related to the depositional environment with higher concentrations of Fe, Al, P, K, and Mg in sediments deposited in alluvial or marine environments and lower concentrations in bedrock derived from eolian sand dunes. Availability of soil nutrients to vegetation is also controlled by the formation of secondary minerals, particularly for P and Ca availability, which, in some geologic settings, appears closely related to variation of CaCO3 and Ca-phosphates in soils. However, the results...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Ecosystems,
bedrock,
desert,
foliar,
nutrient,
This dataset contains a digital version of the Geologic Map of the United States, originally published at a scale of 1:2,500,000 (King and Beikman, 1974b). It excludes Alaska and Hawaii. In addition to the graphical formats, the map key is included in ASCII text. A geographic information system (GIS) allows combining and overlaying of layers for analysis of spatial relations not readily apparent in the standard paper publication. This disc contains only geology. However, digital data on geology, geophysics, and geochemistry can be combined to create useful derivative products-- for example, see Phillips and others (1993).
Mineral Resources Section personnel from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a geologic field survey, including mapping and sampling, in the eastern part of the Bonnifield mining district in the Fairbanks A-1 and A-2 and the Healy D-1 and D-2 quadrangles, Alaska, from June 16 through July 18, 2008. The fieldwork provides basic information critical to building an understanding of Alaska's geology and is part of an integrated program of airborne geophysical surveys followed by geologic mapping. Specifically, this work provides geologic context for geophysical surveys conducted in 2006. Interpretation and synthesis of this data has been presented in professional and trade meetings....
40Ar/39Ar analyses were performed on igneous rocks from the Ray Mountains area of west-central Alaska. The plutonic samples have ages from about 89 Ma to 109 Ma, while the volcanic samples show ranges from about 30 Ma to 64 Ma. The three volcanic samples fall into two age groups: the younger sample, a basalt, has an age of about 30 Ma, while the two older, rhyolitic samples fall between 58 Ma and 64 Ma. Analyses were performed by the University of Alaska Fairbanks Geochronology Laboratory, and results were reported by Paul Layer and Jeff Benowitz. Products included in this data release are: a summary of sample collection method; the laboratory report, analytical data tables and associated metadata; and plots of...
These data were released prior to the October 1, 2016 effective date for the USGS’s policy dictating the review, approval, and release of scientific data as referenced in USGS Survey Manual Chapter 502.8 Fundamental Science Practices: Review and Approval of Scientific Data for Release. The U.S. Geological Survey developed this dataset as part of the Colorado Front Range Infrastructure Resources Project (FRIRP). One goal of the FRIRP was to provide information on the availability of those hydrogeologic resources that are either critical to maintaining infrastructure along the northern Front Range or that may become less available because of urban expansion in the northern Front Range. This dataset extends from the...
This raster depicts the percentage of lithological the hydraulic conductivity (in micrometers per second) of surface or near surface geology. We derived these rasters by calculating the average conductivity for each map unit in combined surficial-bedrock geologic maps. We used state geologic maps (Preliminary Integrated Geologic Map Databases for the United States, Open File Reports 2004-1355, 2005-1305, 2005-1323, 2005-1324, 2005-1325, 2005-1351, and 2006-1272), which depict surficial geology instead of bedrock when the surficial layers are sufficiently deep. For the state maps that do not incorporate surficial geology (i.e., midwestern states), we overlaid surficial geologic map units with thicknesses greater...
Categories: Data,
Map;
Types: ArcGIS REST Map Service,
ArcGIS Service Definition,
Citation,
Downloadable,
Map Service;
Tags: Bedrock,
Conterminous U.S.,
Geology,
Geophysical,
hydraulic conductivity
This workbook summarizes geochemical data for each lithology contained within the USGS Preliminary Integrated Geologic Map Databases for the United States (Open File Reports 2004-1355, 2005-1305, 2005-1323, 2005-1324, 2005-1325, 2005-1351, and 2006-1272). The summarized geochemical data contained in the “Lith Summary” spreadsheet (tab) is used to translate lithologies in state geologic maps into maps of continuous chemical characteristics (see Geochemical and Geophysical Characteristics of the Conterminous United States, http://dx.doi.org/10.5066/F7X0653P). Full details of the data are provided in the “ReadMe” spreadsheet at the beginning of the workbook.
This child item dataset contains a single horizontal-to-vertical spectral ratio (HVSR) measurement from Delaware County, New York, DHVSR8. Raw and processed HVSR data for this HVSR measurement are included in a zipped directory named by the measurement site identifier. The HVSR data-collection sites are designated by a county sequential numbering system (DHVSR8, etc. where "D" indicates Delaware County).
The US Geological Survey, in cooperation with the National Park Service, mapped 35 7.5-minute quadrangles, within a 2-mile-wide+ corridor centered on the Parkway, from BLRI (Blue Ridge Parkway) Mile Post (MP) 0 near Afton, Virginia southward to MP 218 at Cumberland Knob, approximately 1.3 km south of the Virginia – North Carolina State Line. Detailed bedrock geologic mapping for this project was conducted at 1:24,000-scale by systematically traversing roads, trails, creeks, and ridges within and adjacent to the 2-mile-wide+ corridor along the 216.9-mile length of the BLRI in Virginia. Geologic data at more than 23,000 station points were collected during this project (September 2009 – February 2014), with approximately...
Geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) and the University of Alaska Fairbanks (UAF) carried out geologic field surveys, including bedrock mapping and sampling, in the Alaska Highway Corridor from 2006 through 2010. The fieldwork provides basic information critical to building an understanding of Alaska's geology and is part of a broader, integrated program that includes airborne geophysical surveys, bedrock and surficial mapping, a mineral-resource assessment, a geologic-hazards assessment, and other geological studies. This publication contains descriptive, location, and analytical information for samples collected in the Mount Hayes, Tanacross, and Nabesna quadrangles, Alaska,...
Connecticut Bedrock Mining Sites Database (2022) is a comprehensive inventory of active and historic bedrock mine and quarry sites in Connecticut. Developed in 2020-2022 by the Connecticut Geological Survey. Contributors: Harold Moritz, Randolph Steinen, Taryn Isenburg, Zachary Klang, Rebekah Kennedy, David Vohra, Madison Rosen, Margaret Thomas, Madison Knox, Charles Kaiser. Supersedes all previously published bedrock mines maps. Point features include site locations, commodity data, activity status, host rock, references, validation methods, reconciliation of duplicate sites and other information. Area features identify disturbed land and tailings piles resulting from mining activities. The geodatabase is a synthesis...
This child item dataset contains a single horizontal-to-vertical spectral ratio (HVSR) measurement from Orange County, New York, for 39 measurements, OHVSR1 through OHVSR39. Raw and processed HVSR data for this HVSR measurement are included in a zipped directory named by the measurement site identifier. The HVSR data-collection sites are designated by a county sequential numbering system (OHVSR1, OHVSR2, etc. where "O" indicates Orange County).
This page contains horizontal-to-vertical spectral ratio (HVSR) data for 86 measurements, LVHVSR1 through LVHVSR97. In October and November of 2016 and 2017, the U.S. Geological Survey collected horizontal-to-vertical spectral ratio (HVSR) data at 104 sites in the Genesee Valley, Livingston County, New York as part of a saline-groundwater investigation in cooperation with the New York State Department of Environmental Resources. The HVSR technique, commonly referred to as the passive-seismic method, is used to estimate the thickness of unconsolidated sediments and the depth to bedrock (Lane and others, 2008). The passive-seismic method uses a single, broad-band three-component (two horizontal and one vertical)...
These data were released prior to the October 1, 2016 effective date for the USGS’s policy dictating the review, approval, and release of scientific data as referenced in USGS Survey Manual Chapter 502.8 Fundamental Science Practices: Review and Approval of Scientific Data for Release. The U.S. Geological Survey developed this dataset as part of the Colorado Front Range Infrastructure Resources Project (FRIRP). One goal of the FRIRP was to provide information on the availability of those hydrogeologic resources that are either critical to maintaining infrastructure along the northern Front Range or that may become less available because of urban expansion in the northern Front Range. This dataset extends from the...
This data set contains boundaries and tags for major geologic units in Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands. In addition to the polygons representing the areal extent of geologic units, it identifies major faults and continental glaciation in Alaska. The data depict the geology of the bedrock that lies at or near the land surface, but not the distribution of surficial materials such as soils, alluvium, and glacial deposits. This map complements the Generalized Geologic Map of the Conterminous United States by Reed and Bush. The data are generalized from a compilation prepared for use in the Geologic Map of North America, published as a paper map by the Geological Society of America and...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: AK,
Alaska,
Bedrock,
Faults,
Geologic History,
Kasatochi is a small, isolated island volcano in the center of the Aleutian Island chain. It consists of a roughly circular cone approximately 3 km in diameter with a lake-filled central crater that is 1.2 km in diameter and extends from the highest point on the island to sea level. The oldest unit recognized is a thick series of mid-Pleistocene glaciovolcanic deposits consisting of autobrecciated lava, lahars, and volumetrically minor lava masses that we believe to have been emplaced underneath a regional ice cap. This unit is unconformably overlain by several massive Holocene lavas, above which lies a thick sequence of latest-Holocene pyroclastic deposits likely deposited during the crater-forming eruption. The...
We report U-Pb zircon geochronology results for one metavolcanic and one metaplutonic rock sample from the Mount Hayes A-6 Quadrangle of central Alaska. These samples are representative of rock units assigned to the Clearwater terrane of Jones and others (1987), a sequence of greenschist-grade metavolcanic and metasedimentary rocks of poorly constrained age and tectonic origin. Our results indicate a crystallization age of 277.33 +/- 11.84 Ma for a felsic metavolcanic rock, and a 268.05 +/- 11.64 Ma crystallization age for a granitic metaplutonic unit intruding the former.
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