John F. Slack
John Slack is a Scientist Emeritus with the USGS Geology, Energy & Minerals (GEM) Science Center in Reston, VA.
Science and Products
Geological and Pb-isotope data for New England volcanogenic massive sulfide deposits
This dataset accompanies publication “Lead isotopes in New England (USA) volcanogenic massive sulfide deposits: implications for metal sources and pre-accretionary tectonostratigraphic terranes”, published in Canadian Journal of Earth Sciences (see 'Related External Resources' section below). The data encompass Pb-isotope analyses of sulfide mineral separates, mainly galena, as well as...
Sulfide Electron Microprobe Analyses and Petrography of Mineralized Samples from the Stratabound Sheep Creek Sediment-Hosted Zn-Pb-Ag-Sn Prospect, and SHRIMP U-Pb Zircon Data for Metaigneous Rocks in the Bonnifield Mining District, Healy Quadrangle, AK
This data set contains 99 electron microprobe analyses of cassiterite, chalcopyrite, galena, pyrite, sphalerite, and tetrahedrite from seven Sheep Creek drill core samples and one outcrop; and a table that describes the textures, mineralogy, and rock type of 15 thin sections of Sheep Creek drill core and observations from our study and from drill core logging by industry. These data were...
Geochemical and Modal Data for Mesoproterozoic Igneous Rocks of the St. Francois Mountains, Southeast Missouri
This data release accompanies the Data Series report 'Compilation of new and previously published geochemical and modal data for Mesoproterozoic igneous rocks of the St. Francois Mountains, southeast Missouri (https://doi.org/10.3133/ds1080). The compilation includes recently acquired as well as previously published geochemical and modal petrographic data for igneous rocks in the St...
Appendices for Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana
This set of data files are the appendices for paper titled Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana. The dataset consists of 8 appendices, including a histogram of solid bitumen and vitrinite Ro values, gas chromatograms, isotopic data, organic and inorganic geochemical analyses, and x-ray diffraction...
Geochemical Database for Iron Oxide-Copper-Cobalt-Gold-Rare Earth Element Deposits of Southeast Missouri
The Geochemical Database for Iron Oxide-Copper-Cobalt-Gold-Rare Earth Element Deposits of Southeast Missouri (IOCG-REE_GX) contains new geochemical data compilations for samples from IOCG-REE type deposits in which each rock sample has one "best value" determination for each analyzed species, greatly improving speed and efficiency of use. IOCG-REE_GX was created and designed to compile...
Filter Total Items: 69
Sulphide petrology and ore genesis of the stratabound Sheep Creek sediment-hosted Zn–Pb–Ag–Sn prospect, and U–Pb zircon constraints on the timing of magmatism in the northern Alaska Range
The Sheep Creek prospect is a stratabound Zn–Pb–Ag–Sn massive sulfide occurrence in the Bonnifield mining district, northern Alaska Range. The prospect is within a quartz–sericite–graphite–chlorite schist unit associated with Devonian carbonaceous and siliceous metasedimentary rocks. Volcanogenic massive sulfide (VMS) deposits in the district are hosted in felsic metavolcanic rocks (362...
Authors
Cynthia Dusel-Bacon, John N. Aleinikoff, Suzanne Paradise, John F. Slack
Lead isotopes in New England (USA) volcanogenic massive sulphide deposits: Implications for metal sources and pre-accretionary tectonostratigraphic terranes
Lead isotope values for volcanogenic massive sulfide (VMS) deposits provide important insights into metal sources and the nature of pre-accretionary tectonostratigraphic terranes and underlying basements. Deposits of this type in New England formed in diverse tectonic settings including volcanic arcs and backarcs, a supra–subduction zone arc, a rifted forearc foreland basin, and a rifted...
Authors
John F. Slack, Scott Swinden, Stephen Piercey, Robert A. Ayuso, Cees Van Staal, Anne P. LeHuray
A recently discovered trachyte-hosted rare earth element-niobium-zirconium occurrence in northern Maine, USA
Reported here are geological, geophysical, mineralogical, and geochemical data on a previously unknown trachyte-hosted rare earth element (REE)-Nb-Zr occurrence at Pennington Mountain in northern Maine, USA. This occurrence was newly discovered by a regional multiparameter, airborne radiometric survey that revealed anomalously high equivalent Th (eTh) and U (eU), confirmed by a detailed...
Authors
Chunzeng Wang, John F. Slack, Anjana K. Shah, Martin G. Yates, David R. Lentz, Amber T.H. Whittaker, Robert G. Marvinney
Perspectives on premetamorphic stratabound tourmalinites
Stratabound tourmalinites are metallogenically important rocks that locally show a close spatial association with diverse types of mineralization, especially volcanogenic massive sulfides (VMS) and clastic-dominated (CD) Zn-Pb deposits. These tourmalinite occurrences pan the geologic record from Eoarchean to Jurassic. Host lithologies are dominated by clastic metasedimentary rocks but in...
Authors
John F. Slack
Potential for critical mineral deposits in Maine, USA
An analysis of the potential for deposits of critical minerals and elements in Maine presented here includes data and discussions for antimony, beryllium, cesium, chromium, cobalt, graphite, lithium, manganese, niobium, platinum group elements, rhenium, rare earth elements, tin, tantalum, tellurium, titanium, uranium, vanadium, tungsten, and zirconium. Deposits are divided into two...
Authors
John F. Slack, F.M. Beck, David Bradley, M. M. Felch, Robert G. Marvinney, A.T.H. Whittaker
Diagenetic barite-pyrite-wurtzite formation and redox signatures in Triassic mudstone, Brooks Range, northern Alaska
Mineralogical and geochemical studies of interbedded black and gray mudstones in the Triassic part of the Triassic-Jurassic Otuk Formation (northern Alaska) document locally abundant barite and pyrite plus diverse redox signatures. These strata, deposited in an outer shelf setting at paleolatitudes of ~45 to 60°N, show widespread sedimentological evidence for bioturbation. Barite occurs...
Authors
John F. Slack, Ryan J. McAleer, Wayne (Pat) Shanks, Julie A. Dumoulin
Sulfur isotopes of host strata for Howards Pass (Yukon–Northwest Territories) Zn-Pb deposits implicate anaerobic oxidation of methane, not basin stagnation
A new sulfur isotope stratigraphic profile has been developed for Ordovician-Silurian mudstones that host the Howards Pass Zn-Pb deposits (Canada) in an attempt to reconcile the traditional model of a stagnant euxinic basin setting with new contradictory findings. Our analyses of pyrite confirm the up-section 34S enrichment reported previously, but additional observations show parallel...
Authors
Craig A. Johnson, John F. Slack, Julie A. Dumoulin, Karen Duttweiler Kelley, Hendrik Falck
Cobalt
Cobalt is a silvery gray metal that has diverse uses based on certain key properties, including ferromagnetism, hardness and wear-resistance when alloyed with other metals, low thermal and electrical conductivity, high melting point, multiple valences, and production of intense blue colors when combined with silica. Cobalt is used mostly in cathodes in rechargeable batteries and in...
Authors
John F. Slack, Bryn E. Kimball, Kim B. Shedd
Cobalt—Styles of deposits and the search for primary deposits
Cobalt (Co) is a potentially critical mineral. The vast majority of cobalt is a byproduct of copper and (or) nickel production. Cobalt is increasingly used in magnets and rechargeable batteries. More than 50 percent of primary cobalt production is from the Central African Copperbelt. The Central African Copperbelt is the only sedimentary rock-hosted stratiform copper district that...
Authors
Murray W. Hitzman, Arthur A. Bookstrom, John F. Slack, Michael L. Zientek
The hyper-enrichment of V and Zn in black shales of the Late Devonian-Early Mississippian Bakken Formation (USA)
Black shales of the Late Devonian to Early Mississippian Bakken Formation are characterized by high concentrations of organic carbon and the hyper-enrichment (> 500 to 1000s of mg/kg) of V and Zn. Deposition of black shales resulted from shallow seafloor depths that promoted rapid development of euxinic conditions. Vanadium hyper-enrichments, which are unknown in modern environments, are...
Authors
Clint Scott, John F. Slack, Karen Duttweiler Kelley
Transgressive-regressive cycles in the metalliferous, oil-shale-bearing Heath Formation (Upper Mississippian), central Montana
The Upper Mississippian Heath Formation, which accumulated in the Big Snowy Trough of central Montana, has been known for three decades to contain mudrocks highly enriched in Zn, V, Mo, Ni and other metals, and source rocks for oil. The unit has more recently been recognized as a prospective tight oil play. Here we present petrographic, paleontologic, geochemical, and carbon and sulfur...
Authors
Julie A. Dumoulin, Craig A. Johnson, Karen D. Kelley, Palma J. Botterell, Paul C. Hackley, Clint Scott, John F. Slack
Source of salinity in the Broken Hill (Australia) Pb-Zn-Ag deposit: Insights from halogen ratios in fluid inclusions
Ratios of Na/Br, Br/Cl, and I/Cl were determined on leachates of fluid inclusions from the Broken Hill Pb-ZnAg deposit in Australia. Paragenetic relations suggest that whereas all analyzed inclusions formed during or after regional metamorphism, ion ratios are not greatly changed from those of the pre-metamorphic ore-forming fluids. Based on relatively high Br/Cl and I/Cl ratios, and low...
Authors
John F. Slack, D.A. Banks, R.T. Wilkin
Science and Products
Geological and Pb-isotope data for New England volcanogenic massive sulfide deposits
This dataset accompanies publication “Lead isotopes in New England (USA) volcanogenic massive sulfide deposits: implications for metal sources and pre-accretionary tectonostratigraphic terranes”, published in Canadian Journal of Earth Sciences (see 'Related External Resources' section below). The data encompass Pb-isotope analyses of sulfide mineral separates, mainly galena, as well as...
Sulfide Electron Microprobe Analyses and Petrography of Mineralized Samples from the Stratabound Sheep Creek Sediment-Hosted Zn-Pb-Ag-Sn Prospect, and SHRIMP U-Pb Zircon Data for Metaigneous Rocks in the Bonnifield Mining District, Healy Quadrangle, AK
This data set contains 99 electron microprobe analyses of cassiterite, chalcopyrite, galena, pyrite, sphalerite, and tetrahedrite from seven Sheep Creek drill core samples and one outcrop; and a table that describes the textures, mineralogy, and rock type of 15 thin sections of Sheep Creek drill core and observations from our study and from drill core logging by industry. These data were...
Geochemical and Modal Data for Mesoproterozoic Igneous Rocks of the St. Francois Mountains, Southeast Missouri
This data release accompanies the Data Series report 'Compilation of new and previously published geochemical and modal data for Mesoproterozoic igneous rocks of the St. Francois Mountains, southeast Missouri (https://doi.org/10.3133/ds1080). The compilation includes recently acquired as well as previously published geochemical and modal petrographic data for igneous rocks in the St...
Appendices for Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana
This set of data files are the appendices for paper titled Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana. The dataset consists of 8 appendices, including a histogram of solid bitumen and vitrinite Ro values, gas chromatograms, isotopic data, organic and inorganic geochemical analyses, and x-ray diffraction...
Geochemical Database for Iron Oxide-Copper-Cobalt-Gold-Rare Earth Element Deposits of Southeast Missouri
The Geochemical Database for Iron Oxide-Copper-Cobalt-Gold-Rare Earth Element Deposits of Southeast Missouri (IOCG-REE_GX) contains new geochemical data compilations for samples from IOCG-REE type deposits in which each rock sample has one "best value" determination for each analyzed species, greatly improving speed and efficiency of use. IOCG-REE_GX was created and designed to compile...
Filter Total Items: 69
Sulphide petrology and ore genesis of the stratabound Sheep Creek sediment-hosted Zn–Pb–Ag–Sn prospect, and U–Pb zircon constraints on the timing of magmatism in the northern Alaska Range
The Sheep Creek prospect is a stratabound Zn–Pb–Ag–Sn massive sulfide occurrence in the Bonnifield mining district, northern Alaska Range. The prospect is within a quartz–sericite–graphite–chlorite schist unit associated with Devonian carbonaceous and siliceous metasedimentary rocks. Volcanogenic massive sulfide (VMS) deposits in the district are hosted in felsic metavolcanic rocks (362...
Authors
Cynthia Dusel-Bacon, John N. Aleinikoff, Suzanne Paradise, John F. Slack
Lead isotopes in New England (USA) volcanogenic massive sulphide deposits: Implications for metal sources and pre-accretionary tectonostratigraphic terranes
Lead isotope values for volcanogenic massive sulfide (VMS) deposits provide important insights into metal sources and the nature of pre-accretionary tectonostratigraphic terranes and underlying basements. Deposits of this type in New England formed in diverse tectonic settings including volcanic arcs and backarcs, a supra–subduction zone arc, a rifted forearc foreland basin, and a rifted...
Authors
John F. Slack, Scott Swinden, Stephen Piercey, Robert A. Ayuso, Cees Van Staal, Anne P. LeHuray
A recently discovered trachyte-hosted rare earth element-niobium-zirconium occurrence in northern Maine, USA
Reported here are geological, geophysical, mineralogical, and geochemical data on a previously unknown trachyte-hosted rare earth element (REE)-Nb-Zr occurrence at Pennington Mountain in northern Maine, USA. This occurrence was newly discovered by a regional multiparameter, airborne radiometric survey that revealed anomalously high equivalent Th (eTh) and U (eU), confirmed by a detailed...
Authors
Chunzeng Wang, John F. Slack, Anjana K. Shah, Martin G. Yates, David R. Lentz, Amber T.H. Whittaker, Robert G. Marvinney
Perspectives on premetamorphic stratabound tourmalinites
Stratabound tourmalinites are metallogenically important rocks that locally show a close spatial association with diverse types of mineralization, especially volcanogenic massive sulfides (VMS) and clastic-dominated (CD) Zn-Pb deposits. These tourmalinite occurrences pan the geologic record from Eoarchean to Jurassic. Host lithologies are dominated by clastic metasedimentary rocks but in...
Authors
John F. Slack
Potential for critical mineral deposits in Maine, USA
An analysis of the potential for deposits of critical minerals and elements in Maine presented here includes data and discussions for antimony, beryllium, cesium, chromium, cobalt, graphite, lithium, manganese, niobium, platinum group elements, rhenium, rare earth elements, tin, tantalum, tellurium, titanium, uranium, vanadium, tungsten, and zirconium. Deposits are divided into two...
Authors
John F. Slack, F.M. Beck, David Bradley, M. M. Felch, Robert G. Marvinney, A.T.H. Whittaker
Diagenetic barite-pyrite-wurtzite formation and redox signatures in Triassic mudstone, Brooks Range, northern Alaska
Mineralogical and geochemical studies of interbedded black and gray mudstones in the Triassic part of the Triassic-Jurassic Otuk Formation (northern Alaska) document locally abundant barite and pyrite plus diverse redox signatures. These strata, deposited in an outer shelf setting at paleolatitudes of ~45 to 60°N, show widespread sedimentological evidence for bioturbation. Barite occurs...
Authors
John F. Slack, Ryan J. McAleer, Wayne (Pat) Shanks, Julie A. Dumoulin
Sulfur isotopes of host strata for Howards Pass (Yukon–Northwest Territories) Zn-Pb deposits implicate anaerobic oxidation of methane, not basin stagnation
A new sulfur isotope stratigraphic profile has been developed for Ordovician-Silurian mudstones that host the Howards Pass Zn-Pb deposits (Canada) in an attempt to reconcile the traditional model of a stagnant euxinic basin setting with new contradictory findings. Our analyses of pyrite confirm the up-section 34S enrichment reported previously, but additional observations show parallel...
Authors
Craig A. Johnson, John F. Slack, Julie A. Dumoulin, Karen Duttweiler Kelley, Hendrik Falck
Cobalt
Cobalt is a silvery gray metal that has diverse uses based on certain key properties, including ferromagnetism, hardness and wear-resistance when alloyed with other metals, low thermal and electrical conductivity, high melting point, multiple valences, and production of intense blue colors when combined with silica. Cobalt is used mostly in cathodes in rechargeable batteries and in...
Authors
John F. Slack, Bryn E. Kimball, Kim B. Shedd
Cobalt—Styles of deposits and the search for primary deposits
Cobalt (Co) is a potentially critical mineral. The vast majority of cobalt is a byproduct of copper and (or) nickel production. Cobalt is increasingly used in magnets and rechargeable batteries. More than 50 percent of primary cobalt production is from the Central African Copperbelt. The Central African Copperbelt is the only sedimentary rock-hosted stratiform copper district that...
Authors
Murray W. Hitzman, Arthur A. Bookstrom, John F. Slack, Michael L. Zientek
The hyper-enrichment of V and Zn in black shales of the Late Devonian-Early Mississippian Bakken Formation (USA)
Black shales of the Late Devonian to Early Mississippian Bakken Formation are characterized by high concentrations of organic carbon and the hyper-enrichment (> 500 to 1000s of mg/kg) of V and Zn. Deposition of black shales resulted from shallow seafloor depths that promoted rapid development of euxinic conditions. Vanadium hyper-enrichments, which are unknown in modern environments, are...
Authors
Clint Scott, John F. Slack, Karen Duttweiler Kelley
Transgressive-regressive cycles in the metalliferous, oil-shale-bearing Heath Formation (Upper Mississippian), central Montana
The Upper Mississippian Heath Formation, which accumulated in the Big Snowy Trough of central Montana, has been known for three decades to contain mudrocks highly enriched in Zn, V, Mo, Ni and other metals, and source rocks for oil. The unit has more recently been recognized as a prospective tight oil play. Here we present petrographic, paleontologic, geochemical, and carbon and sulfur...
Authors
Julie A. Dumoulin, Craig A. Johnson, Karen D. Kelley, Palma J. Botterell, Paul C. Hackley, Clint Scott, John F. Slack
Source of salinity in the Broken Hill (Australia) Pb-Zn-Ag deposit: Insights from halogen ratios in fluid inclusions
Ratios of Na/Br, Br/Cl, and I/Cl were determined on leachates of fluid inclusions from the Broken Hill Pb-ZnAg deposit in Australia. Paragenetic relations suggest that whereas all analyzed inclusions formed during or after regional metamorphism, ion ratios are not greatly changed from those of the pre-metamorphic ore-forming fluids. Based on relatively high Br/Cl and I/Cl ratios, and low...
Authors
John F. Slack, D.A. Banks, R.T. Wilkin