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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...
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...
This report describes the results of geologic mapping and sample analysis from the Richardson district, east-central Alaska.
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...
This data release contains three spreadsheets that have aluminum-26 and beryllium-10 concentrations for samples collected in and near Sparta, North Carolina in 2021-2022. These samples were prepared for burial dating by the Reston Cosmogenic Nuclide (RECON) Lab and measured via accelerator mass spectrometry at the Purdue Rare Isotope Measurement (PRIME) Lab. The file “Sparta_SiteLocations_Odom.csv” contains site locations and interpreted ages; measurements of aluminum-26 and beryllium-10 and related data are located in respective .csv files.
Cassiterite (SnO2), a main ore mineral in tin deposits, was collected by multiple Russian geologists or obtained from museum collections in both the USA and Russia and dated at the U.S. Geological Survey. The dated samples represent four different mining districts spanning the entire country from the village of Pitkäranta in the west (31° E Longitude) to the Merekskoe Deposit in the Russian Far East (134°E Longitude). The samples were recovered from a variety of host deposit types that range from the Proterozoic to Phanerozoic. Cassiterite (in the form of mounted loose grains) was prepared and analyzed for direct age dating on a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) system at the...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: GGGSC,
Geology, Geophysics, and Geochemistry Science Center,
LA-ICP-MS,
MRP,
Mineral Resources Program,
This dataset accompanies planned publication 'Determining fault geometry through the transport-parallel distribution of thermochronometer cooling ages'. The Ar/Ar data is for samples that record the thermal history of the area. The geochronology provides time constraints for the thermal histories studied in the manuscript. Samples were collected from Nepal, overseen by Nadine McQuarrie (University of Pittsburgh), who sent them to the USGS Denver Argon Geochronology Laboratory for Ar/Ar analysis.
Categories: Data;
Tags: 40Ar/39Ar,
Argon Geochronology Laboratory,
GGGSC,
Geochemistry,
Geology, Geophysics, and Geochemistry Science Center,
In 2016, with National Park Service support, several previously undated plutons were sampled in Glacier Bay National Park and Preserve along the west side of Glacier Bay for age determinations. Geochronologic analyses were conducted to determine the ages of the plutonic rocks in the Glacier Bay area. Five samples were collected by Frederic Wilson (USGS Alaska Science Center), from Dundas Bay and Geikie Inlet, and dated by laser ablation-inductively coupled plasma mass spectrometry U-Pb methods. The dates obtained ranged from approximately 112-118 Ma, indicating that these samples are younger than the Saint Elias plutonic suite (ca. 160 Ma-130Ma), which runs along the same trend as the sampled rocks to the south.
Ar/Ar data are reported from minerals and rocks that were collected as part of a mineral resource investigation of the Tonopah, Divide, and Goldfield districts in Nevada. Data are reported from 92 samples and associated standards from eight separate neutron irradiations in the Denver USGS TRIGA reactor, including separated mineral grains and whole rocks. Data were collected by infrared laser heating of irradiated samples, either incremental heating or fusion, and analysis by multi-collector mass spectrometry. The reported data have been corrected for blanks, radioactive decay, and interfering nucleogenic reactions associated with sample irradiation.
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: 40Ar/39Ar,
Ar,
Divide district,
Geochemistry,
Goldfield,
This report summarizes the cosmogenic beryllium-10 (10Be) geochronologic results from boulders deposited on moraines in the Stura Valley of the Maritime Alps, the southwestern most extent of the European Alpine mountain chain, northwestern Italy. Within this report are detailed the methodologies used to collect samples of whole rock, determine the concentrations of cosmogenic 10Be in purified quartz isolated from those samples, and use those nuclide concentrations to calculate surface exposure ages. This report should be used as supplementary material for any publication(s) that uses the nuclide concentrations and/or ages reported herein. This version supersedes all previous age estimates and reports.
This U.S. Geological Survey (USGS) data release provides monazite and xenotime geochronology from Proterozoic rocks collected from outcrop in central Colorado and whole rock isotope geochemistry, and zircon and monazite geochronology from a Proterozoic rock sampled from a drill core from western Colorado. The drill core sample was collected from the 1 Paradox Valley injection core near Bedrock, CO at a depth of 4,755-4,765 m below the surface. The samples were in order to constrain the age, provenance, metamorphic history, and geochemical character of basement terranes in Colorado.
Categories: Data;
Tags: Colorado,
Geochemistry,
USGS Science Data Catalog (SDC),
USGS:63bed9e9d34e92aad3cda906,
geochemistry,
Burnsville Cove in Bath and Highland Counties (Virginia, USA) is a karst region in the Valley and Ridge Province of the Appalachian Mountains. The region contains many caves in Silurian to Devonian limestone, and is well suited for examining geologic controls on cave location and cave passage morphology. In Burnsville Cove, many caves are located preferentially near the axes of synclines and anticlines. For example, Butler Cave is an elongate cave where the trunk channel follows the axis of Sinking Creek syncline and most of the side passages follow joints at right angles to the syncline axis. In contrast, the Water Sinks Subway Cave, Owl Cave, and Helictite Cave have abundant maze patterns, and are located near...
Categories: Data,
Data Release - In Progress;
Tags: Bath County,
Burnsville Cove,
Butler Cave,
Geomorphology,
Highland County,
This dataset accompanies the publication, 'In situ LA-ICPMS U-Pb dating of cassiterite without a known-age matrix-matched reference material: Examples from worldwide tin deposits spanning the Proterozoic to Tertiary', published in Chemical Geology (https://doi.org/10.1016/j.chemgeo.2018.03.008), which reports a LA-ICPMS analytical procedure for dating cassiterite, a main ore mineral in tin deposits, with no need for an independently dated matrix-matched cassiterite standard.
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service,
Shapefile;
Tags: Bolivia,
Brazil,
China,
Geochemistry,
Geology, Geophysics, and Geochemistry Science Center,
These data are U-Pb sensitive high-resolution ion microprobe (SHRIMP) geochronology data from quartz porphyry dikes for the study of the Butte mining district, U.S.A. Results of the study are described and interpreted in Lund and others (2018).
This dataset provides geochronologic and geochemical data for selected metasedimentary and associated rock samples collected in the Lane Mountain area about 20 kilometers northeast of Barstow, California. Geochronologic data were obtained for 24 samples, and geochemical data were obtained for 5 of these. The dataset consists of four tables in csv (comma separated values) format: (1) sample localities and lithology; (2) LA-SF-ICPMS (Laser Ablation Sector Field Inductively Coupled Plasma Mass Spectrometry) U-Pb (uranium-lead) zircon geochronologic data; (3) SHRIMP-RG (Sensitive High-Resolution Ion Microprobe-Reverse Geometry) U-Pb zircon geochronologic data; and (4) whole-rock geochemical data determined by ICP-AES-MS...
This location is part of the Arizona Mineral Industry Location System (AzMILS), an inventory of mineral occurences, prospects and mine locations in Arizona. Cochise742 is located in T20S R23E Sec 34 ALL in the Hay Mountain - 7.5 Min quad. This collection consists of various reports, maps, records and related materials acquired by the Arizona Department of Mines and Mineral Resources regarding mining properties in Arizona. Information was obtained by various means, including the property owners, exploration companies, consultants, verbal interviews, field visits, newspapers and publications. Some sections may be redacted for copyright. Please see the access statement.
The Preliminary Interpretive Report 2004-3B, "Bedrock geologic map of the Livengood SW C-3 and SE C-4 quadrangles, Tolovana mining district, Alaska," is the bedrock geologic map of an approximately 123-square-mile area in the central Livengood Quadrangle, Alaska.
This data release includes raw detrital zircon U-Pb data for isolated sandstones in Upper Triassic deposits of the Auld Lang Syne basin of northwest Nevada, USA. Detrital zircon U-Pb data for 11 sandstone samples (3269 zircon U-Pb dates) were acquired via LA-ICP-MS at the University of Arizona LaserChron Center for 11 sandstone samples. Primary insights from the data are twofold: 1) The data provide information about sediment provenance and indicate that sediment of the Auld Lang Syne basin was primarily derived from near the ancestral Ouachita orogen of Texas and Oklahoma. Sediment was transported to the Auld Lang Syne basin by a Late Triassic transcontinental river system, recorded today by the Upper Triassic...
We have constrained the age of the Nussbaum Gravel at Baculite Mesa, CO using cosmogenic Al-26/Be-10 isochron burial dating. Two samples, a coarse sand and a fine gravel, were prepared for burial dating at the Reston Cosmogenic Nuclide (RECON) Lab and measured via accelerator mass spectrometry at the Purdue Rare Isotope Measurement (PRIME) Lab. The results of this work are summarized in the file “BaculiteMesa_SiteLocation_Odom.csv”, which contains site data and burial age calculations; measurements of aluminum-26 and beryllium-10, as well as related data, are located in respective .csv files. We calculated respective minimum and maximum burial ages for the sand (1.25 ± 0.08 Ma and 1.66 ± 0.12 Ma) and gravel (1.44...
This dataset accompanies the planned publication “Mantle Melting in Regions of Thick Continental Lithosphere-Examples from Late Cretaceous and Younger Volcanic Rocks, Southern Rocky Mountains, Colorado” in the journal Geosphere. The dataset includes 40Ar/39Ar data for 19 samples from the Rabbit Ears volcanic field and from the Elkhead Mountains in northcentral Colorado, USA. Samples were collected from this area by James Mize (University of Colorado, Boulder), Lang Farmer (University of Colorado, Boulder), and Michael Cosca (USGS) with helpful input about sampling locations by Kenzie Turner (USGS). The samples were analyzed in the Denver Argon Geochronology Laboratory at the USGS from September, 2013 to July, 2017.
Categories: Data;
Tags: 40Ar/39Ar,
Colorado,
Denver Argon Geochronology Laboratory,
Elkhead Mountains,
GGGSC,
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