Albert H Hofstra (Former Employee)
Science and Products
Filter Total Items: 83
Deposit classification scheme for the Critical Minerals Mapping Initiative Global Geochemical Database Deposit classification scheme for the Critical Minerals Mapping Initiative Global Geochemical Database
A challenge for the global economy is to meet the growing demand for commodities used in today’s advanced technologies. Critical minerals are commodities (for example, elements, compounds, minerals) deemed vital to the economic and national security of individual countries that are vulnerable to supply disruption. The national geological agencies of Australia, Canada, and the United...
Authors
Albert H. Hofstra, Vladimir Lisitsin, Louise Corriveau, Suzanne Paradis, Jan Peter, Kathleen Lauziere, Christopher Lawley, Michael Gadd, Jean-Luc Pilote, Ian Honsberger, Evgeniy Bastrakov, David Champion, Karol Czarnota, Michael Doublier, David Huston, Oliver Raymond, Simon VanDerWielen, Poul Emsbo, Matthew Granitto, Douglas C. Kreiner
Focus areas for data acquisition for potential domestic resources of 11 critical minerals in the conterminous United States, Hawaii, and Puerto Rico—Aluminum, cobalt, graphite, lithium, niobium, platinum-group elements, rare earth elements, tantalum, tin, Focus areas for data acquisition for potential domestic resources of 11 critical minerals in the conterminous United States, Hawaii, and Puerto Rico—Aluminum, cobalt, graphite, lithium, niobium, platinum-group elements, rare earth elements, tantalum, tin,
In response to a need for information on potential domestic sources of critical minerals, the Earth Mapping Resources Initiative (Earth MRI) was established to identify and prioritize areas for acquisition of new geologic mapping, geophysical data, and elevation data to improve our knowledge of the geologic framework of the United States. Phase 1 of Earth MRI concentrated on those...
Authors
Jane M. Hammarstrom, Connie L. Dicken, Warren C. Day, Albert H. Hofstra, Benjamin J. Drenth, Anjana K. Shah, Anne E. McCafferty, Laurel G. Woodruff, Nora K. Foley, David A. Ponce, Thomas P. Frost, Lisa L. Stillings
Systems-deposits-commodities-critical minerals table for the earth mapping resources initiative Systems-deposits-commodities-critical minerals table for the earth mapping resources initiative
To define and prioritize focus areas across the United States with resource potential for 35 critical minerals in a few years’ time, the U.S Geological Survey Earth Mapping Resources Initiative (Earth MRI) required an efficient approach to streamline workflow. A mineral systems approach based on current understanding of how ore deposits that contain critical minerals form and relate to...
Authors
Albert H. Hofstra, Douglas C. Kreiner
Absence of magnetite microlites, geochemistry of magnetite veins and replacements in IOA deposits, SE Missouri, USA: Relations to intermediate intrusions Absence of magnetite microlites, geochemistry of magnetite veins and replacements in IOA deposits, SE Missouri, USA: Relations to intermediate intrusions
The paragenesis, textures, and chemical compositions of magnetite in two mafic to intermediate intrusions and four IOA deposits in SE Missouri were studied to discriminate between igneous and hydrothermal sources. In this study, we found that replacement magnetite with mineral inclusion-rich cores yields erroneously high Ti, Al, Si, Mg, and Mn contents as determined by EMP and LA-ICP-MS...
Authors
Corey J. Meighan, Albert H. Hofstra, David Adams, Erin E. Marsh, Heather A. Lowers, Alan Koenig
Geochemistry of hematite veins in IOA-IOCG deposits of SE Missouri, USA: Relation to felsic magmatism and caldera lakes Geochemistry of hematite veins in IOA-IOCG deposits of SE Missouri, USA: Relation to felsic magmatism and caldera lakes
The paragenesis, textures, and chemical compositions of secondary hematite in regional potassic altered rhyolites, four IOA deposits, the sedimentary iron deposit at Pilot Knob and the Boss IOCG deposit in SE Missouri were determined and compared to primary magnetite from the IOA and IOCG deposits. Magnetite is composed of elements characteristics of mafic to intermediate intrusions...
Authors
Corey J. Meighan, Albert H. Hofstra, Erin E. Marsh, Heather A. Lowers, Alan Koenig
Crustal architecture beneath the southern Midcontinent (USA) and controls on Mesoproterozoic iron-oxide mineralization from 3D geophysical models Crustal architecture beneath the southern Midcontinent (USA) and controls on Mesoproterozoic iron-oxide mineralization from 3D geophysical models
Several types of critical mineral-bearing ore deposits in the southern Midcontinent region of the U.S. are hosted in Mesoproterozoic igneous rocks largely concealed beneath Paleozoic cover. Discerning the architecture of igneous intrusions and volcanic centers in the crust is fundamental to understanding the geologic evolution of this vast region and its mineral resources. To advance the
Authors
Anne E. McCafferty, Jeffrey D. Phillips, Albert H. Hofstra, Warren C. Day
Tourmaline boron and strontium isotope systematics reveal magmatic fluid pulses and external fluid influx in a giant iron oxide-apatite (IOA) deposit Tourmaline boron and strontium isotope systematics reveal magmatic fluid pulses and external fluid influx in a giant iron oxide-apatite (IOA) deposit
Tourmaline is a common boron-bearing mineral in hydrothermal system and has been widely used as a mineral probe to reconstruct geological processes because of its broad range in composition and resistance to metasomatic alteration. The origin of Kiruna-type iron oxide-apatite (IOA) deposits, commonly linked to andesitic subvolcanic or volcanic rocks, is highly controversial. Constraints...
Authors
Zhi-kun Su, Xinfu Zhao, Li-ping Zeng, Kui-dong Zhao, Albert H. Hofstra
Noble gas data from Goldfield and Tonopah epithermal Au-Ag deposits, ancestral Cascades Arc, USA: Evidence for a primitive mantle volatile source Noble gas data from Goldfield and Tonopah epithermal Au-Ag deposits, ancestral Cascades Arc, USA: Evidence for a primitive mantle volatile source
The He, Ne, and Ar isotopic composition of fluid inclusions in ore and gangue minerals were analyzed to determine the source of volatiles in the high-grade Goldfield and Tonopah epithermal Au-Ag deposits in southwestern Nevada, USA. Ar and Ne are mainly atmospheric, whereas He has only a minor atmospheric component. Corrected 3He/4He ratios (with atmospheric He removed) range widely from...
Authors
Andrew H. Manning, Albert H. Hofstra
The Valmy thrust sheet: A regional structure formed during the protracted assembly of the Roberts Mountains allochthon, Nevada, USA The Valmy thrust sheet: A regional structure formed during the protracted assembly of the Roberts Mountains allochthon, Nevada, USA
A synthesis of field, biostratigraphic, detrital zircon geochronologic, and remote sensing data across north-central Nevada, United States, defines a thick, regionally extensive sheet of Middle–Upper Ordovician Valmy Formation quartzite that structurally overlies deformed early Paleozoic units of the Roberts Mountains allochthon. Late Paleozoic regional unconformities that record...
Authors
Christopher S. Holm-Denoma, Albert H. Hofstra, Barnaby W. Rockwell, Paula J. Noble
Isotopic data for Late Cretaceous intrusions and associated altered and mineralized rocks in the Big Belt Mountains, Montana Isotopic data for Late Cretaceous intrusions and associated altered and mineralized rocks in the Big Belt Mountains, Montana
The quartz monzodiorite of Mount Edith and the concentrically zoned intrusive suite of Boulder Baldy constitute the principal Late Cretaceous igneous intrusions hosted by Mesoproterozoic sedimentary rocks of the Newland Formation in the Big Belt Mountains, Montana. These calc-alkaline plutonic masses are manifestations of subduction-related magmatism that prevailed along the western edge...
Authors
Edward A. du Bray, Daniel M. Unruh, Albert H. Hofstra
Mineral thermometry and fluid inclusion studies of the Pea Ridge iron oxide-apatite–rare earth element deposit, Mesoproterozoic St. Francois Mountains Terrane, southeast Missouri, USA Mineral thermometry and fluid inclusion studies of the Pea Ridge iron oxide-apatite–rare earth element deposit, Mesoproterozoic St. Francois Mountains Terrane, southeast Missouri, USA
Mineral thermometry and fluid inclusion studies were conducted on variably altered and mineralized samples from the Mesoproterozoic Pea Ridge iron oxide-apatite (IOA)-rare earth element (REE) deposit in order to constrain P-T conditions, fluid chemistry, and the source of salt and volatiles during early magnetite and later REE mineralization. Scanning electron microscopy (SEM)...
Authors
Albert H. Hofstra, Corey J. Meighan, Xinyu Song, Iain Samson, Erin E. Marsh, Heather A. Lowers, Poul Emsbo, Andrew G. Hunt
Critical elements in Carlin, epithermal, and orogenic gold deposits Critical elements in Carlin, epithermal, and orogenic gold deposits
Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered...
Authors
Richard J. Goldfarb, Albert H. Hofstra, Stuart F. Simmons
Science and Products
Filter Total Items: 83
Deposit classification scheme for the Critical Minerals Mapping Initiative Global Geochemical Database Deposit classification scheme for the Critical Minerals Mapping Initiative Global Geochemical Database
A challenge for the global economy is to meet the growing demand for commodities used in today’s advanced technologies. Critical minerals are commodities (for example, elements, compounds, minerals) deemed vital to the economic and national security of individual countries that are vulnerable to supply disruption. The national geological agencies of Australia, Canada, and the United...
Authors
Albert H. Hofstra, Vladimir Lisitsin, Louise Corriveau, Suzanne Paradis, Jan Peter, Kathleen Lauziere, Christopher Lawley, Michael Gadd, Jean-Luc Pilote, Ian Honsberger, Evgeniy Bastrakov, David Champion, Karol Czarnota, Michael Doublier, David Huston, Oliver Raymond, Simon VanDerWielen, Poul Emsbo, Matthew Granitto, Douglas C. Kreiner
Focus areas for data acquisition for potential domestic resources of 11 critical minerals in the conterminous United States, Hawaii, and Puerto Rico—Aluminum, cobalt, graphite, lithium, niobium, platinum-group elements, rare earth elements, tantalum, tin, Focus areas for data acquisition for potential domestic resources of 11 critical minerals in the conterminous United States, Hawaii, and Puerto Rico—Aluminum, cobalt, graphite, lithium, niobium, platinum-group elements, rare earth elements, tantalum, tin,
In response to a need for information on potential domestic sources of critical minerals, the Earth Mapping Resources Initiative (Earth MRI) was established to identify and prioritize areas for acquisition of new geologic mapping, geophysical data, and elevation data to improve our knowledge of the geologic framework of the United States. Phase 1 of Earth MRI concentrated on those...
Authors
Jane M. Hammarstrom, Connie L. Dicken, Warren C. Day, Albert H. Hofstra, Benjamin J. Drenth, Anjana K. Shah, Anne E. McCafferty, Laurel G. Woodruff, Nora K. Foley, David A. Ponce, Thomas P. Frost, Lisa L. Stillings
Systems-deposits-commodities-critical minerals table for the earth mapping resources initiative Systems-deposits-commodities-critical minerals table for the earth mapping resources initiative
To define and prioritize focus areas across the United States with resource potential for 35 critical minerals in a few years’ time, the U.S Geological Survey Earth Mapping Resources Initiative (Earth MRI) required an efficient approach to streamline workflow. A mineral systems approach based on current understanding of how ore deposits that contain critical minerals form and relate to...
Authors
Albert H. Hofstra, Douglas C. Kreiner
Absence of magnetite microlites, geochemistry of magnetite veins and replacements in IOA deposits, SE Missouri, USA: Relations to intermediate intrusions Absence of magnetite microlites, geochemistry of magnetite veins and replacements in IOA deposits, SE Missouri, USA: Relations to intermediate intrusions
The paragenesis, textures, and chemical compositions of magnetite in two mafic to intermediate intrusions and four IOA deposits in SE Missouri were studied to discriminate between igneous and hydrothermal sources. In this study, we found that replacement magnetite with mineral inclusion-rich cores yields erroneously high Ti, Al, Si, Mg, and Mn contents as determined by EMP and LA-ICP-MS...
Authors
Corey J. Meighan, Albert H. Hofstra, David Adams, Erin E. Marsh, Heather A. Lowers, Alan Koenig
Geochemistry of hematite veins in IOA-IOCG deposits of SE Missouri, USA: Relation to felsic magmatism and caldera lakes Geochemistry of hematite veins in IOA-IOCG deposits of SE Missouri, USA: Relation to felsic magmatism and caldera lakes
The paragenesis, textures, and chemical compositions of secondary hematite in regional potassic altered rhyolites, four IOA deposits, the sedimentary iron deposit at Pilot Knob and the Boss IOCG deposit in SE Missouri were determined and compared to primary magnetite from the IOA and IOCG deposits. Magnetite is composed of elements characteristics of mafic to intermediate intrusions...
Authors
Corey J. Meighan, Albert H. Hofstra, Erin E. Marsh, Heather A. Lowers, Alan Koenig
Crustal architecture beneath the southern Midcontinent (USA) and controls on Mesoproterozoic iron-oxide mineralization from 3D geophysical models Crustal architecture beneath the southern Midcontinent (USA) and controls on Mesoproterozoic iron-oxide mineralization from 3D geophysical models
Several types of critical mineral-bearing ore deposits in the southern Midcontinent region of the U.S. are hosted in Mesoproterozoic igneous rocks largely concealed beneath Paleozoic cover. Discerning the architecture of igneous intrusions and volcanic centers in the crust is fundamental to understanding the geologic evolution of this vast region and its mineral resources. To advance the
Authors
Anne E. McCafferty, Jeffrey D. Phillips, Albert H. Hofstra, Warren C. Day
Tourmaline boron and strontium isotope systematics reveal magmatic fluid pulses and external fluid influx in a giant iron oxide-apatite (IOA) deposit Tourmaline boron and strontium isotope systematics reveal magmatic fluid pulses and external fluid influx in a giant iron oxide-apatite (IOA) deposit
Tourmaline is a common boron-bearing mineral in hydrothermal system and has been widely used as a mineral probe to reconstruct geological processes because of its broad range in composition and resistance to metasomatic alteration. The origin of Kiruna-type iron oxide-apatite (IOA) deposits, commonly linked to andesitic subvolcanic or volcanic rocks, is highly controversial. Constraints...
Authors
Zhi-kun Su, Xinfu Zhao, Li-ping Zeng, Kui-dong Zhao, Albert H. Hofstra
Noble gas data from Goldfield and Tonopah epithermal Au-Ag deposits, ancestral Cascades Arc, USA: Evidence for a primitive mantle volatile source Noble gas data from Goldfield and Tonopah epithermal Au-Ag deposits, ancestral Cascades Arc, USA: Evidence for a primitive mantle volatile source
The He, Ne, and Ar isotopic composition of fluid inclusions in ore and gangue minerals were analyzed to determine the source of volatiles in the high-grade Goldfield and Tonopah epithermal Au-Ag deposits in southwestern Nevada, USA. Ar and Ne are mainly atmospheric, whereas He has only a minor atmospheric component. Corrected 3He/4He ratios (with atmospheric He removed) range widely from...
Authors
Andrew H. Manning, Albert H. Hofstra
The Valmy thrust sheet: A regional structure formed during the protracted assembly of the Roberts Mountains allochthon, Nevada, USA The Valmy thrust sheet: A regional structure formed during the protracted assembly of the Roberts Mountains allochthon, Nevada, USA
A synthesis of field, biostratigraphic, detrital zircon geochronologic, and remote sensing data across north-central Nevada, United States, defines a thick, regionally extensive sheet of Middle–Upper Ordovician Valmy Formation quartzite that structurally overlies deformed early Paleozoic units of the Roberts Mountains allochthon. Late Paleozoic regional unconformities that record...
Authors
Christopher S. Holm-Denoma, Albert H. Hofstra, Barnaby W. Rockwell, Paula J. Noble
Isotopic data for Late Cretaceous intrusions and associated altered and mineralized rocks in the Big Belt Mountains, Montana Isotopic data for Late Cretaceous intrusions and associated altered and mineralized rocks in the Big Belt Mountains, Montana
The quartz monzodiorite of Mount Edith and the concentrically zoned intrusive suite of Boulder Baldy constitute the principal Late Cretaceous igneous intrusions hosted by Mesoproterozoic sedimentary rocks of the Newland Formation in the Big Belt Mountains, Montana. These calc-alkaline plutonic masses are manifestations of subduction-related magmatism that prevailed along the western edge...
Authors
Edward A. du Bray, Daniel M. Unruh, Albert H. Hofstra
Mineral thermometry and fluid inclusion studies of the Pea Ridge iron oxide-apatite–rare earth element deposit, Mesoproterozoic St. Francois Mountains Terrane, southeast Missouri, USA Mineral thermometry and fluid inclusion studies of the Pea Ridge iron oxide-apatite–rare earth element deposit, Mesoproterozoic St. Francois Mountains Terrane, southeast Missouri, USA
Mineral thermometry and fluid inclusion studies were conducted on variably altered and mineralized samples from the Mesoproterozoic Pea Ridge iron oxide-apatite (IOA)-rare earth element (REE) deposit in order to constrain P-T conditions, fluid chemistry, and the source of salt and volatiles during early magnetite and later REE mineralization. Scanning electron microscopy (SEM)...
Authors
Albert H. Hofstra, Corey J. Meighan, Xinyu Song, Iain Samson, Erin E. Marsh, Heather A. Lowers, Poul Emsbo, Andrew G. Hunt
Critical elements in Carlin, epithermal, and orogenic gold deposits Critical elements in Carlin, epithermal, and orogenic gold deposits
Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered...
Authors
Richard J. Goldfarb, Albert H. Hofstra, Stuart F. Simmons