A5016787904- Geological and Geochemical Analysis
- Geochemistry and Geologic Mapping
- Geology and Paleoclimatology Research
- earthquake and tectonic studies
- Geological Studies and Exploration
- High-pressure geophysics and materials
- Paleontology and Stratigraphy of Fossils
- Hydrocarbon exploration and reservoir analysis
- Geological and Geophysical Studies Worldwide
- Landslides and related hazards
- Radioactive element chemistry and processing
- Geochemistry and Elemental Analysis
- Rangeland and Wildlife Management
- Geological formations and processes
- Mineralogy and Gemology Studies
- Botany, Ecology, and Taxonomy Studies
- Geological Modeling and Analysis
- Methane Hydrates and Related Phenomena
- Water Quality and Resources Studies
- Marine and environmental studies
- Climate change and permafrost
- Planetary Science and Exploration
- Astro and Planetary Science
- Archaeology and Natural History
- Geological and Geophysical Studies
Denver Federal Center
2007-2023
United States Geological Survey
2011-2023
State Street (United States)
2021
Pacific Island Ecosystems Research Center
2018
Australian National University
2002-2007
George Washington University
2007
Indiana University Bloomington
2007
Dartmouth College
1977-1979
Research Article| January 01, 2006 Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington Complex, Delaware: Morphology, cathodoluminescence backscattered electron zoning, SHRIMP U-Pb geochronology zircon monazite John N. Aleinikoff; Aleinikoff 1U.S. Geological Survey, MS 963, Denver Federal Center, Denver, Colorado 80225, USA Search for other works by this author on: GSW Google Scholar William S. Schenck; Schenck 2Delaware Newark, Delaware 19716, Margaret O. Plank;...
The Killingworth dome of south-central Connecticut occurs at the southern end Bronson Hill belt. It is composed tonalitic and trondhjemitic orthogneisses (Killingworth complex) bimodal metavolcanic rocks (Middletown that display calc-alkaline affinities. Orthogneisses complex (Boulder Lake gneiss, 456 ± 6 Ma; Pond Meadow ∼460 Ma) were emplaced about same time as eruption deposition volcanic-sedimentary Middletown Formation, 449 4 Higganum 459 Ma). Hidden gneiss (339 3 a pluton in core dome,...
Research Article| March 01, 2003 SHRIMP U-Pb geochronology of Neoproterozoic Windermere Supergroup, central Idaho: Implications for rifting western Laurentia and synchroneity Sturtian glacial deposits Karen Lund; Lund 1U.S. Geological Survey, Denver, Colorado 80225, USA Search other works by this author on: GSW Google Scholar John N. Aleinikoff; Aleinikoff Karl V. Evans; Evans C. Mark Fanning 2Australian National University, Canberra, ACT 0200, Australia GSA Bulletin (2003) 115 (3): 349–372....
Research Article| November 01, 2008 Origin and paleoclimatic significance of late Quaternary loess in Nebraska: Evidence from stratigraphy, chronology, sedimentology, geochemistry Daniel R. Muhs; Muhs † 1U.S. Geological Survey, MS 980, Box 25046, Federal Center, Denver, Colorado 80225, USA †E-mail: dmuhs@usgs.gov Search for other works by this author on: GSW Google Scholar E. Arthur Bettis, III; III 2Department Geoscience, University Iowa, Iowa City, 52242, John N. Aleinikoff; Aleinikoff...
New sensitive high resolution ion microprobe (SHRIMP) UPb zircon analyses from two tuffs and a felsic flow in the middle upper Belt Supergroup of northwestern Montana significantly refine age sedimentation for this very thick (15-20 km) Middle Proterozoic stratigraphic sequence. In ascending order, results are (1) 1454 ± 9 Ma tuff part Helena Formation at Logan Pass, Glacier National Park; (2) 1443 7 regionally restricted porphyritic rhyolite to quartz latite Purcell Lava Yaak River region;...
Research Article| December 01, 1999 Late Quaternary loess in northeastern Colorado: Part I—Age and paleoclimatic significance Daniel R. Muhs; Muhs 1U.S. Geological Survey, M.S. 980, Box 25046, Federal Center, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar John N. Aleinikoff; Aleinikoff 2U.S. 963, Thomas W. Stafford, Jr; Jr 3Institute of Arctic Alpine Research, Campus 450, University Colorado, Boulder, 80309 Rolf Kihl; Kihl Josh Been; Been Shannon A....
Research Article| March 01, 2010 SHRIMP U-Pb dating of recurrent Cryogenian and Late Cambrian–Early Ordovician alkalic magmatism in central Idaho: Implications for Rodinian rift tectonics K. Lund; Lund † 1U.S. Geological Survey, MS 973, Denver Federal Center, Box 25046, Denver, Colorado 80225, USA †E-mail: klund@usgs.gov Search other works by this author on: GSW Google Scholar J.N. Aleinikoff; Aleinikoff 2U.S. 963, K.V. Evans; Evans E.A. duBray; duBray E.H. Dewitt; Dewitt D.M. Unruh Author...
This study utilizes Pb isotope data to identify flow paths and sources for Mississippi Valley-type ores in the midcontinent of United States with emphasis on Old New Lead Belt subdistricts southeast Missouri. Nearly 150 new analyses are reported which characterize systematics both ore samples hosted by sedimentary rocks away from districts. A subset has been analyzed sulfur isotopes. The nonore contain trace amounts largely metal- rich FeS 2 (termed sulfide Pb). These metal-rich phases...
Research Article| September 01, 1987 Evolution of the Early Proterozoic Colorado province: Constraints from U-Pb geochronology John C. Reed, Jr; Jr 1U.S. Geological Survey, M.S. 913, Box 25046, Federal Center, Denver, 80225 Search for other works by this author on: GSW Google Scholar M. E. Bickford; Bickford 2Department Geology, University Kansas, Lawrence, Kansas 66095 Wayne R. Premo; Premo 3U.S. 963, N. Aleinikoff; Aleinikoff S. Pallister 4U.S. 903, Geology (1987) 15 (9): 861–865....
Research Article| November 01, 2008 Isotopic evidence for the diversity of late Quaternary loess in Nebraska: Glaciogenic and nonglaciogenic sources John N. Aleinikoff; Aleinikoff † 1U.S. Geological Survey, MS 963, Denver, Colorado 80225, USA †E-mail: jaleinikoff@usgs.gov Search other works by this author on: GSW Google Scholar Daniel R. Muhs; Muhs 2U.S. 980, E. Arthur Bettis, III; III 3Department Geoscience, University Iowa, Iowa City, 52242, William C. Johnson; Johnson 4Department...
Research Article| April 01, 1985 Petrology and tectonic significance of augen gneiss from a belt Mississippian granitoids in the Yukon-Tanana terrane, east-central Alaska CYNTHIA DUSEL-BACON; DUSEL-BACON 1Branch Alaskan Geology, U.S. Geological Survey, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar JOHN N. ALEINIKOFF 2Branch Isotope Denver, Colorado 80225 GSA Bulletin (1985) 96 (4): 411–425....
The Bedrock Geologic Map of Vermont is the result a cooperative agreement between U.S. Geological Survey (USGS) and State Vermont. State's complex geology spans 1.4 billion years Earth's history. new map comes 50 after most recent by Charles G. Doll others in 1961 full 150 since publication first geologic Edward Hitchcock 1861. At scale 1:100,000, shows an uncommon level detail for maps. Mapped rock units are primarily based on lithology, or type, to facilitate derivative studies multiple...
The Blackbird district, east-central Idaho, contains the largest known Co reserves in United States. origin of strata-hosted Co-Cu ± Au mineralization at has been a matter controversy for decades. In order to differentiate among possible genetic models deposits, including various combinations volcanic, sedimentary, magmatic, and metamorphic processes, we used U-Pb geochronology xenotime, monazite, zircon establish time constraints ore formation. New age data reported here were obtained using...
Rare earth element (REE)-rich breccia pipes (600,000 t @ 12% REO) are preserved along the margins of 136 Mt Pea Ridge magnetite-apatite deposit, within Mesoproterozoic (~1.47 Ga) volcanic-plutonic rocks St. Francois Mountains terrane in southeastern Missouri, USA. The cut rhyolite-hosted magnetite and contain clasts nearly all local bedrock mineralized lithologies. Grains monazite xenotime were extracted from pipe samples for SHRIMP U-Pb geochronology; both minerals also dated one polished...
Research Article| December 01, 1999 Late Quaternary loess in northeastern Colorado: Part II—Pb isotopic evidence for the variability of sources John N. Aleinikoff; Aleinikoff 1U.S. Geological Survey, M.S. 963, Box 25046, Denver Federal Center, Denver, Colorado 80225 Search other works by this author on: GSW Google Scholar Daniel R. Muhs; Muhs 2U.S. 980, Rebecca Sauer; Sauer C. Mark Fanning 3Research School Earth Sciences, Australian National University, Canberra ACT 0200, Australia GSA...