Albert H Hofstra (Former Employee)
Science and Products
Filter Total Items: 82
Geology and mineral resources of the North-Central Idaho Sagebrush Focal Area: Chapter C in Mineral resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, Oregon, Utah, and Wyoming Geology and mineral resources of the North-Central Idaho Sagebrush Focal Area: Chapter C in Mineral resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, Oregon, Utah, and Wyoming
Summary The U.S. Department of the Interior has proposed to withdraw approximately 10 million acres of Federal lands from mineral entry (subject to valid existing rights) from 12 million acres of lands defined as Sagebrush Focal Areas (SFAs) in Idaho, Montana, Nevada, Oregon, Utah, and Wyoming (for further discussion on the lands involved see Scientific Investigations Report 2016–5089–A)...
Authors
Karen Lund, Lukas Zürcher, Albert H. Hofstra, Bradley S. Van Gosen, Mary Ellen Benson, Stephen E. Box, Eric D. Anderson, Donald I. Bleiwas, Jacob DeAngelo, Ronald M. Drake, Gregory L. Fernette, Stuart A. Giles, Jonathan M. G. Glen, Jon E. Haacke, John D. Horton, David A. John, Gilpin R. Robinson, Barnaby W. Rockwell, Carma A. San Juan, Brian N. Shaffer, Steven M. Smith, Colin F. Williams
By
Geology, Energy, and Minerals Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Energy & Minerals Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center, National Minerals Information Center
Extreme variation of sulfur isotopic compositions in pyrite from the Qiuling sediment-hosted gold deposit, West Qinling orogen, central China: An in situ SIMS study with implications for the source of sulfur Extreme variation of sulfur isotopic compositions in pyrite from the Qiuling sediment-hosted gold deposit, West Qinling orogen, central China: An in situ SIMS study with implications for the source of sulfur
High spatial resolution textural (scanning electron microscope (SEM)), chemical (electron microprobe (EMP)) and laser ablation-inductively coupled plasma-mass spec- trometry (LA-ICP-MS)), and sulfur isotopic (secondary ion mass spectrometry (SIMS)) analyses of pyrite from the Qiuling sediment-hosted gold deposit (232±4 Ma) in the West Qinling orogen, central China were conducted to...
Authors
Lei Chen, Xian-hua Li, Jian-wei Li, Albert H. Hofstra, Yu Liu, Alan E. Koenig
Pre-eruptive conditions of the Hideaway Park topaz rhyolite: Insights into metal source and evolution of magma parental to the Henderson porphyry molybdenum deposit, Colorado Pre-eruptive conditions of the Hideaway Park topaz rhyolite: Insights into metal source and evolution of magma parental to the Henderson porphyry molybdenum deposit, Colorado
The Hideaway Park tuff is the only preserved extrusive volcanic unit related to the Red Mountain intrusive complex, which produced the world-class Henderson porphyry Mo deposit. Located within the Colorado Mineral Belt, USA, Henderson is the second largest Climax-type Mo deposit in the world, and is therefore an excellent location to investigate magmatic processes leading to Climax-type...
Authors
Celestine N. Mercer, Albert H. Hofstra, Todor I. Todorov, Julie Roberge, Alain Burgisser, David T. Adams, Michael A. Cosca
Silicate melt inclusion evidence for extreme pre-eruptive enrichment and post-eruptive depletion of lithium in silicic volcanic rocks of the western United States: implications for the origin of lithium-rich brines Silicate melt inclusion evidence for extreme pre-eruptive enrichment and post-eruptive depletion of lithium in silicic volcanic rocks of the western United States: implications for the origin of lithium-rich brines
To evaluate whether anatectic and/or highly fractionated lithophile element-enriched rhyolite tuffs deposited in arid lacustrine basins lose enough lithium during eruption, lithification, and weathering to generate significant Li brine resources, pre-eruptive melt compositions, preserved in inclusions, and the magnitude of post-eruptive Li depletions, evident in host rhyolites, were...
Authors
Albert H. Hofstra, T.I. Todorov, C.N. Mercer, D.T. Adams, E.E. Marsh
Ore genesis constraints on the Idaho cobalt belt from fluid inclusion gas, noble gas isotope, and ion ratio analyses--a reply Ore genesis constraints on the Idaho cobalt belt from fluid inclusion gas, noble gas isotope, and ion ratio analyses--a reply
Burlinson (2013) questions the veracity of the H2 concentrations reported for fluid inclusion extracts from minerals in the Idaho cobalt belt (Table 2; Landis and Hofstra, 2012) and suggests that they are an analytical artifact of electron-impact mass spectrometry. He also declares that H2 should not be present in fluid inclusions because it is invariably lost by diffusion and is never...
Authors
Albert H. Hofstra, Gary P. Landis
Analyzing legacy U.S. Geological Survey geochemical databases using GIS: applications for a national mineral resource assessment Analyzing legacy U.S. Geological Survey geochemical databases using GIS: applications for a national mineral resource assessment
This report emphasizes geographic information system analysis and the display of data stored in the legacy U.S. Geological Survey National Geochemical Database for use in mineral resource investigations. Geochemical analyses of soils, stream sediments, and rocks that are archived in the National Geochemical Database provide an extensive data source for investigating geochemical anomalies...
Authors
Douglas B. Yager, Albert H. Hofstra, Matthew Granitto
Science and Products
Filter Total Items: 82
Geology and mineral resources of the North-Central Idaho Sagebrush Focal Area: Chapter C in Mineral resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, Oregon, Utah, and Wyoming Geology and mineral resources of the North-Central Idaho Sagebrush Focal Area: Chapter C in Mineral resources of the Sagebrush Focal Areas of Idaho, Montana, Nevada, Oregon, Utah, and Wyoming
Summary The U.S. Department of the Interior has proposed to withdraw approximately 10 million acres of Federal lands from mineral entry (subject to valid existing rights) from 12 million acres of lands defined as Sagebrush Focal Areas (SFAs) in Idaho, Montana, Nevada, Oregon, Utah, and Wyoming (for further discussion on the lands involved see Scientific Investigations Report 2016–5089–A)...
Authors
Karen Lund, Lukas Zürcher, Albert H. Hofstra, Bradley S. Van Gosen, Mary Ellen Benson, Stephen E. Box, Eric D. Anderson, Donald I. Bleiwas, Jacob DeAngelo, Ronald M. Drake, Gregory L. Fernette, Stuart A. Giles, Jonathan M. G. Glen, Jon E. Haacke, John D. Horton, David A. John, Gilpin R. Robinson, Barnaby W. Rockwell, Carma A. San Juan, Brian N. Shaffer, Steven M. Smith, Colin F. Williams
By
Geology, Energy, and Minerals Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Energy & Minerals Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center, National Minerals Information Center
Extreme variation of sulfur isotopic compositions in pyrite from the Qiuling sediment-hosted gold deposit, West Qinling orogen, central China: An in situ SIMS study with implications for the source of sulfur Extreme variation of sulfur isotopic compositions in pyrite from the Qiuling sediment-hosted gold deposit, West Qinling orogen, central China: An in situ SIMS study with implications for the source of sulfur
High spatial resolution textural (scanning electron microscope (SEM)), chemical (electron microprobe (EMP)) and laser ablation-inductively coupled plasma-mass spec- trometry (LA-ICP-MS)), and sulfur isotopic (secondary ion mass spectrometry (SIMS)) analyses of pyrite from the Qiuling sediment-hosted gold deposit (232±4 Ma) in the West Qinling orogen, central China were conducted to...
Authors
Lei Chen, Xian-hua Li, Jian-wei Li, Albert H. Hofstra, Yu Liu, Alan E. Koenig
Pre-eruptive conditions of the Hideaway Park topaz rhyolite: Insights into metal source and evolution of magma parental to the Henderson porphyry molybdenum deposit, Colorado Pre-eruptive conditions of the Hideaway Park topaz rhyolite: Insights into metal source and evolution of magma parental to the Henderson porphyry molybdenum deposit, Colorado
The Hideaway Park tuff is the only preserved extrusive volcanic unit related to the Red Mountain intrusive complex, which produced the world-class Henderson porphyry Mo deposit. Located within the Colorado Mineral Belt, USA, Henderson is the second largest Climax-type Mo deposit in the world, and is therefore an excellent location to investigate magmatic processes leading to Climax-type...
Authors
Celestine N. Mercer, Albert H. Hofstra, Todor I. Todorov, Julie Roberge, Alain Burgisser, David T. Adams, Michael A. Cosca
Silicate melt inclusion evidence for extreme pre-eruptive enrichment and post-eruptive depletion of lithium in silicic volcanic rocks of the western United States: implications for the origin of lithium-rich brines Silicate melt inclusion evidence for extreme pre-eruptive enrichment and post-eruptive depletion of lithium in silicic volcanic rocks of the western United States: implications for the origin of lithium-rich brines
To evaluate whether anatectic and/or highly fractionated lithophile element-enriched rhyolite tuffs deposited in arid lacustrine basins lose enough lithium during eruption, lithification, and weathering to generate significant Li brine resources, pre-eruptive melt compositions, preserved in inclusions, and the magnitude of post-eruptive Li depletions, evident in host rhyolites, were...
Authors
Albert H. Hofstra, T.I. Todorov, C.N. Mercer, D.T. Adams, E.E. Marsh
Ore genesis constraints on the Idaho cobalt belt from fluid inclusion gas, noble gas isotope, and ion ratio analyses--a reply Ore genesis constraints on the Idaho cobalt belt from fluid inclusion gas, noble gas isotope, and ion ratio analyses--a reply
Burlinson (2013) questions the veracity of the H2 concentrations reported for fluid inclusion extracts from minerals in the Idaho cobalt belt (Table 2; Landis and Hofstra, 2012) and suggests that they are an analytical artifact of electron-impact mass spectrometry. He also declares that H2 should not be present in fluid inclusions because it is invariably lost by diffusion and is never...
Authors
Albert H. Hofstra, Gary P. Landis
Analyzing legacy U.S. Geological Survey geochemical databases using GIS: applications for a national mineral resource assessment Analyzing legacy U.S. Geological Survey geochemical databases using GIS: applications for a national mineral resource assessment
This report emphasizes geographic information system analysis and the display of data stored in the legacy U.S. Geological Survey National Geochemical Database for use in mineral resource investigations. Geochemical analyses of soils, stream sediments, and rocks that are archived in the National Geochemical Database provide an extensive data source for investigating geochemical anomalies...
Authors
Douglas B. Yager, Albert H. Hofstra, Matthew Granitto