Filters: Tags: Metamorphic Rocks (X)124 results (166ms)
Geologic map and digital database of the San Bernardino Wash7.5 minute quadrangle, Riverside County, California
This data set maps and describes the geology of the San Bernardino Wash 7.5 minutequadrangle, Riverside County, southern California. The quadrangle, situated inJoshua Tree National Park in the eastern Transverse Ranges physiographic andstructural province, encompasses parts of the northwestern Eagle Mountains,east-central Pinto Basin, and eastern Pinto Mountains.The quadrangle is underlain by a basement terrane comprising metamorphosedProterozoic strata, Mesozoic plutonic rocks, and Jurassic and Mesozoic and (or)Cenozoic hypabyssal dikes. The basement terrane is capped by a widespread Tertiaryerosion surface preserved in remnants in the Pinto and Eagle Mountains and buriedbeneath Cenozoic deposits in Pinto Basin....
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...
View west toward granite rocks (photograph WM01) on west side of river mile 190.1 from Hundred and Ninety Mile canyon.
View southwest and downriver toward Vishnu Schist below Tapeats Sandstone, river mile 112.6.
Aerial view northwest toward Horn Creek Rapids, river mile 90.9, showing numerous pegmatite and granite dikes in black Vishnu Schist. Inner canyon is 1,300 feet deep here.
Aerial view south and downriver from river mile 211.9 toward a Precambrian “island” of schist (photographs WM07, WM08, WM09) during the basal Cambrian sea encroachment, right bank of river mile 212.5.
Black river-polished amphibolitic schist, west (left) bank of river mile 127.5.
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...
Sources of stream sediments in the granulite terrain of the Walawe Ganga Basin, Sri Lanka, indicated by rare earth element geochemistry
EM13. View northwest toward southeast side of Precambrian Zoroaster Granite “island” of Cambrian seaway
View northwest toward southeast side of Precambrian Zoroaster Granite “island” of Cambrian seaway, onlapped by Cambrian Tapeats Sandstone, from Tonto Trail, south of river mile 85.1.
Pegmatite dikes in schist, south bank of river mile 80.5.
View southeast and downriver toward metamorphic rocks with granitic dikes, north of Granite Park, river mile 208.2.
River-polished Vishnu Schist, north bank of Crystal Rapids, river mile 98.7.
Fortymile mining district electromagnetic and magnetic airborne geophysical survey, data compilation
The Fortymile electromagnetic and magnetic airborne geophysical survey data were acquired with a DIGHEM-V Electromagnetic (EM) system and a cesium magnetometer. The EM and magnetic sensors were flown at a height of 30 meters (m). In addition the survey recorded data from radar and laser altimeters, a GPS navigation system, 50/60 Hz monitors and a video camera. Flights were performed with an AS-350-B2 Squirrel helicopter at a mean terrain clearance of 60 m along N-S survey flight lines with a spacing of 400 m. Tie lines were flown perpendicular to the flight lines at intervals of approximately 4,800 m
Bedrock geologic map of the Livengood SW C-3 and SE C-4 quadrangles, Tolovana mining district, Alaska
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.
The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States (https://doi.org/10.5066/F7WH2N65) represents a seamless, spatial database of 48 State geologic maps that range from 1:50,000 to 1:1,000,000 scale. A national digital geologic map database is essential in interpreting other datasets that support numerous types of national-scale studies and assessments, such as those that provide geochemistry, remote sensing, or geophysical data. The SGMC is a compilation of the individual U.S. Geological Survey releases of the Preliminary Integrated Geologic Map Databases for the United States. The SGMC geodatabase also contains updated data for seven States and seven entirely new State geologic...
Major Findings on the Nature of Acoustic Basement Rocks in the Alboran and South Balearic Basins from the Basacalb Cruise (TTR-9, Leg 3).
U-Pb zircon age data from meta-igneous rocks in the Clearwater Mountains, Mount Hayes A-6 Quadrangle, Alaska
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.