Steve Ludington
Steve is a Geologist Emeritus at Geology, Minerals, Energy, and Geophysics Science Center in Menlo Park, CA. He is a graduate of Stanford University (B.S.) and the University of Colorado (M.S. and Ph.D.). He joined the USGS in 1974 and retired from full-time work in 2012. His skills are in petrology, volcanology, mineral deposit controls, and mineral-resource assessment.
Science and Products
Whole-Rock Geochemical Data for Cenozoic Silicic Igneous and Hydrothermal Rocks from Colorado, New Mexico, Arizona, Nevada, and California
This data release presents whole-rock geochemical data for a suite of silicic igneous and magmatic-hydrothermal rocks from the western Cordillera of the United States. Samples were mainly collected from Eocene to Miocene high-silica igneous rocks and other nearby igneous and hydrothermal±magmatic rocks. These data were collected to help define highly evolved magma systems that can be...
Cenozoic Highly Evolved Rhyolites of the Western Cordillera of the Conterminous United States
The use of data analytics and digital mineral prospectivity mapping has become increasingly important to mineral resource assessment in recent years. Necessary information for many forms of such modeling are expert-validated training sets. Previous work defined occurrence and grade and tonnage models for Climax-type porphyry molybdenum deposits (Singer and others, 1986; Ludington and...
Locatable Mineral Assessment Tracts for the U.S. Geological Survey Sagebrush Mineral Resource Assessment Project
The polygon (vector) feature class represents locatable mineral resource assessment tracts (tracts of land) associated with the Department of the Interior (DOI) Sagebrush Focal Areas in Montana, Wyoming and Utah, central Idaho, and the Oregon-Nevada-Idaho border area. The mineral resources tracts are geographic areas that were assessed by the U.S. Geological Survey (USGS) and were...
Filter Total Items: 17
Porphyry copper potential of the U.S. Southern Basin and Range using ASTER data integrated with geochemical and geologic datasets to assess potential near-surface deposits in well-explored permissive tracts
ArcGIS was used to spatially assess and rank potential porphyry copper deposits using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data together with geochemical and geologic datasets in order to estimate undiscovered deposits in the southern Basin and Range Province in the southwestern United States. The assessment was done using a traditional expert opinion...
Authors
John C. Mars, Gilpin R. Robinson,, Jane M. Hammarstrom, Lukas Zürcher, Helen A. Whitney, Federico Solano, Mark E. Gettings, Stephen Ludington
Tectono-magmatic evolution of porphyry belts in the central Tethys region of Turkey, the Caucasus, Iran, western Pakistan, and southern Afghanistan
Exploration in the central Tethys region of Turkey, Armenia, Azerbaijan, Georgia, Iran, and western Pakistan has led to the identification of the giant Reko Diq (24 Mt Cu and 1300 t Au), Sar Cheshmeh (8.9 Mt Cu and 0.46 Mt Mo), Sungun (5.1 Mt Cu and 0.20 Mt Mo), and Kadjaran (4.6 Mt Cu, 0.94 Mt Mo, and 1100 t Au), and 10 other large (1–2 Mt Cu) porphyry deposits including Saindak...
Authors
Lukas Zürcher, Arthur A. Bookstrom, Jane M. Hammarstrom, John C. Mars, Stephen Ludington, Michael L. Zientek, Pamela Dunlap, John C. Wallis
Probabilistic mineral resource assessment of U.S. Territories of the Caribbean Basin and adjacent areas: Progress report
The U.S. Geological Survey is partnering with the IberoAmerican Association of Geological and Mining Surveys (ASGMI) to conduct an assessment of undiscovered metallic and non-metallic resources in the Greater Antilles region. The assessment plans to provide science-based information on the geologic availability of these resources for development, land-use planning, and decision making...
Authors
Lukas Zürcher, Floyd Gray, Stephen Ludington, Frederic H. Wilson, Greta J. Orris, Mark D. Cocker, Mark E. Gettings, Timothy Hayes
New method to integrate remotely sensed hydrothermal alteration mapping into quantitative mineral resource assessments
Hydrothermal alteration data mapped using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were compiled into hydrothermal alteration polygons for use in an assessment of porphyry copper mineral resource potential in the southwestern United States. Hydrothermal alteration polygons along with geochemistry, gravity and magnetic, lithologic, and deposit and...
Authors
John C. Mars, Jane M. Hammarstrom, Gilpin R. Robinson,, Stephen Ludington, Lukas Zürcher, Helen W. Folger, Mark E. Gettings, Federico Solano, Thomas Kress
Undiscovered porphyry copper resources in the Urals—A probabilistic mineral resource assessment
A probabilistic mineral resource assessment of metal resources in undiscovered porphyry copper deposits of the Ural Mountains in Russia and Kazakhstan was done using a quantitative form of mineral resource assessment. Permissive tracts were delineated on the basis of mapped and inferred subsurface distributions of igneous rocks assigned to tectonic zones that include magmatic arcs where...
Authors
Jane M. Hammarstrom, Mark J. Mihalasky, Stephen Ludington, Jeffrey Phillips, Byron R. Berger, Paul Denning, Connie Dicken, John C. Mars, Michael L. Zientek, Richard J. Herrington, Reimar Seltmann
Geology and mineral resources of the Sheldon-Hart Mountain National Wildlife Refuge Complex (Oregon and Nevada), the Southeastern Oregon and North-Central Nevada, and the Southern Idaho and Northern Nevada (and Utah) Sagebrush Focal Areas: Chapter B in
SummaryThe 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
Peter Vikre, Mary Ellen Benson, Donald I. Bleiwas, Joseph P. Colgan, Pamela M. Cossette, Jacob DeAngelo, Connie Dicken, Ronald M. Drake, Edward A. du Bray, Gregory Fernette, Jonathan M.G. Glen, Jon Haacke, Susan M. Hall, Albert H. Hofstra, David A. John, Stephen Ludington, Mark J. Mihalasky, James J. Rytuba, Brian N. Shaffer, Lisa L. Stillings, John C. Wallis, Colin F. Williams, Douglas B. Yager, Lukas Zürcher
By
Energy and Mineral Resources Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center, National Minerals Information Center
Relationship between porphyry systems, crustal preservation levels, and amount of exploration in magmatic belts of the Central Tethys Region
Tectonic, geologic, geochemical, geochronologic, and ore deposit data from the U.S. Geological Survey-led assessment of 26 porphyry belts identified in the central Tethys region of Turkey, the Caucasus, Iran, western Pakistan, and southern Afghanistan relate porphyry mineralization to the tectonomagmatic evolution of the region and associated subduction and postsubduction processes...
Authors
Lukas Zürcher, Jane M. Hammarstrom, John C. Mars, Stephen Ludington, Michael L. Zientek
Porphyry copper assessment of the Tethys region of western and southern Asia: Chapter V in Global mineral resource assessment
A probabilistic mineral resource assessment of undiscovered resources in porphyry copper deposits in the Tethys region of western and southern Asia was carried out as part of a global mineral resource assessment led by the U.S. Geological Survey (USGS). The purpose of the study was to delineate geographic areas as permissive tracts for the occurrence of porphyry copper deposits at a...
Authors
Lukas Zürcher, Arthur A. Bookstrom, Jane M. Hammarstrom, John C. Mars, Stephen Ludington, Michael L. Zientek, Pamela Dunlap, John C. Wallis, Lawrence Drew, David M. Sutphin, Byron R. Berger, Richard J. Herrington, Mario Billa, Ilkay Kuşcu, Charles J. Moon, Jeremy P. Richards
By
Energy and Mineral Resources Mission Area, Energy Resources Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Energy & Minerals Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Porphyry copper assessment of northeast Asia: Far East Russia and northeasternmost China: Chapter W in Global mineral resource assessment
The U.S. Geological Survey assesses resources (mineral, energy, water, environmental, and biologic) at regional, national, and global scales to provide science in support of land management and decision making. Mineral resource assessments provide a synthesis of available information about where mineral deposits are known and suspected to be in the Earth’s crust, which commodities may be...
Authors
Mark J. Mihalasky, Stephen Ludington, Dmitriy V. Alexeiev, Thomas P. Frost, Thomas D. Light, Deborah A. Briggs, Jane M. Hammarstrom, John C. Wallis, Arthur A. Bookstrom, Andre Panteleyev
Porphyry copper assessment of the Central Asian Orogenic Belt and eastern Tethysides: China, Mongolia, Russia, Pakistan, Kazakhstan, Tajikistan, and India: Chapter X in Global mineral resource assessment
The U.S. Geological Survey collaborated with international colleagues to assess undiscovered resources in porphyry copper deposits in the Central Asian Orogenic Belt and eastern Tethysides. These areas host 20 known porphyry copper deposits, including the world class Oyu Tolgoi deposit in Mongolia that was discovered in the late 1990s. The study area covers major parts of the world’s...
Authors
Mark J. Mihalasky, Stephen Ludington, Jane M. Hammarstrom, Dmitriy V. Alexeiev, Thomas P. Frost, Thomas D. Light, Gilpin Robinson, Deborah A. Briggs, John C. Wallis, Robert J. Miller, Arthur A. Bookstrom, Andre Panteleyev, Andre Chitalin, Reimar Seltmann, Yan Guangsheng, Lian Changyun, Mao Jingwen, Li Jinyi, Xiao Keyan, Qiu Ruizhao, Shao Jianbao, Shai Gangyi, Du Yuliang
By
Energy and Mineral Resources Mission Area, Energy Resources Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Energy & Minerals Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Potash: a global overview of evaporate-related potash resources, including spatial databases of deposits, occurrences, and permissive tracts
Potash is mined worldwide to provide potassium, an essential nutrient for food crops. Evaporite-hosted potash deposits are the largest source of salts that contain potassium in water-soluble form, including potassium chloride, potassium-magnesium chloride, potassium sulfate, and potassium nitrate. Thick sections of evaporitic salt that form laterally continuous strata in sedimentary...
Authors
Greta J. Orris, Mark D. Cocker, Pamela Dunlap, Jeff Wynn, Gregory T. Spanski, Deborah A. Briggs, Leila Gass, James D. Bliss, Karen Sue Bolm, Chao Yang, Bruce R. Lipin, Stephen Ludington, Robert J. Miller, Mirosław Słowakiewicz
By
Energy and Mineral Resources Mission Area, Energy Resources Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Energy & Minerals Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Porphyry copper assessment of East and Southeast Asia: Philippines, Taiwan (Republic of China), Republic of Korea (South Korea), and Japan
The U.S. Geological Survey collaborated with member countries of the Coordinating Committee for Geoscience Programmes in East and Southeast Asia (CCOP) on an assessment of the porphyry copper resources of East and Southeast Asia as part of a global mineral resource assessment. The assessment covers the Philippines in Southeast Asia, and the Republic of Korea (South Korea), Taiwan...
Authors
Jane M. Hammarstrom, Arthur A. Bookstrom, Michael W. Demarr, Connie Dicken, Stephen Ludington, Gilpin Robinson, Michael L. Zientek
Science and Products
Whole-Rock Geochemical Data for Cenozoic Silicic Igneous and Hydrothermal Rocks from Colorado, New Mexico, Arizona, Nevada, and California
This data release presents whole-rock geochemical data for a suite of silicic igneous and magmatic-hydrothermal rocks from the western Cordillera of the United States. Samples were mainly collected from Eocene to Miocene high-silica igneous rocks and other nearby igneous and hydrothermal±magmatic rocks. These data were collected to help define highly evolved magma systems that can be...
Cenozoic Highly Evolved Rhyolites of the Western Cordillera of the Conterminous United States
The use of data analytics and digital mineral prospectivity mapping has become increasingly important to mineral resource assessment in recent years. Necessary information for many forms of such modeling are expert-validated training sets. Previous work defined occurrence and grade and tonnage models for Climax-type porphyry molybdenum deposits (Singer and others, 1986; Ludington and...
Locatable Mineral Assessment Tracts for the U.S. Geological Survey Sagebrush Mineral Resource Assessment Project
The polygon (vector) feature class represents locatable mineral resource assessment tracts (tracts of land) associated with the Department of the Interior (DOI) Sagebrush Focal Areas in Montana, Wyoming and Utah, central Idaho, and the Oregon-Nevada-Idaho border area. The mineral resources tracts are geographic areas that were assessed by the U.S. Geological Survey (USGS) and were...
Filter Total Items: 17
Porphyry copper potential of the U.S. Southern Basin and Range using ASTER data integrated with geochemical and geologic datasets to assess potential near-surface deposits in well-explored permissive tracts
ArcGIS was used to spatially assess and rank potential porphyry copper deposits using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data together with geochemical and geologic datasets in order to estimate undiscovered deposits in the southern Basin and Range Province in the southwestern United States. The assessment was done using a traditional expert opinion...
Authors
John C. Mars, Gilpin R. Robinson,, Jane M. Hammarstrom, Lukas Zürcher, Helen A. Whitney, Federico Solano, Mark E. Gettings, Stephen Ludington
Tectono-magmatic evolution of porphyry belts in the central Tethys region of Turkey, the Caucasus, Iran, western Pakistan, and southern Afghanistan
Exploration in the central Tethys region of Turkey, Armenia, Azerbaijan, Georgia, Iran, and western Pakistan has led to the identification of the giant Reko Diq (24 Mt Cu and 1300 t Au), Sar Cheshmeh (8.9 Mt Cu and 0.46 Mt Mo), Sungun (5.1 Mt Cu and 0.20 Mt Mo), and Kadjaran (4.6 Mt Cu, 0.94 Mt Mo, and 1100 t Au), and 10 other large (1–2 Mt Cu) porphyry deposits including Saindak...
Authors
Lukas Zürcher, Arthur A. Bookstrom, Jane M. Hammarstrom, John C. Mars, Stephen Ludington, Michael L. Zientek, Pamela Dunlap, John C. Wallis
Probabilistic mineral resource assessment of U.S. Territories of the Caribbean Basin and adjacent areas: Progress report
The U.S. Geological Survey is partnering with the IberoAmerican Association of Geological and Mining Surveys (ASGMI) to conduct an assessment of undiscovered metallic and non-metallic resources in the Greater Antilles region. The assessment plans to provide science-based information on the geologic availability of these resources for development, land-use planning, and decision making...
Authors
Lukas Zürcher, Floyd Gray, Stephen Ludington, Frederic H. Wilson, Greta J. Orris, Mark D. Cocker, Mark E. Gettings, Timothy Hayes
New method to integrate remotely sensed hydrothermal alteration mapping into quantitative mineral resource assessments
Hydrothermal alteration data mapped using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were compiled into hydrothermal alteration polygons for use in an assessment of porphyry copper mineral resource potential in the southwestern United States. Hydrothermal alteration polygons along with geochemistry, gravity and magnetic, lithologic, and deposit and...
Authors
John C. Mars, Jane M. Hammarstrom, Gilpin R. Robinson,, Stephen Ludington, Lukas Zürcher, Helen W. Folger, Mark E. Gettings, Federico Solano, Thomas Kress
Undiscovered porphyry copper resources in the Urals—A probabilistic mineral resource assessment
A probabilistic mineral resource assessment of metal resources in undiscovered porphyry copper deposits of the Ural Mountains in Russia and Kazakhstan was done using a quantitative form of mineral resource assessment. Permissive tracts were delineated on the basis of mapped and inferred subsurface distributions of igneous rocks assigned to tectonic zones that include magmatic arcs where...
Authors
Jane M. Hammarstrom, Mark J. Mihalasky, Stephen Ludington, Jeffrey Phillips, Byron R. Berger, Paul Denning, Connie Dicken, John C. Mars, Michael L. Zientek, Richard J. Herrington, Reimar Seltmann
Geology and mineral resources of the Sheldon-Hart Mountain National Wildlife Refuge Complex (Oregon and Nevada), the Southeastern Oregon and North-Central Nevada, and the Southern Idaho and Northern Nevada (and Utah) Sagebrush Focal Areas: Chapter B in
SummaryThe 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
Peter Vikre, Mary Ellen Benson, Donald I. Bleiwas, Joseph P. Colgan, Pamela M. Cossette, Jacob DeAngelo, Connie Dicken, Ronald M. Drake, Edward A. du Bray, Gregory Fernette, Jonathan M.G. Glen, Jon Haacke, Susan M. Hall, Albert H. Hofstra, David A. John, Stephen Ludington, Mark J. Mihalasky, James J. Rytuba, Brian N. Shaffer, Lisa L. Stillings, John C. Wallis, Colin F. Williams, Douglas B. Yager, Lukas Zürcher
By
Energy and Mineral Resources Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center, National Minerals Information Center
Relationship between porphyry systems, crustal preservation levels, and amount of exploration in magmatic belts of the Central Tethys Region
Tectonic, geologic, geochemical, geochronologic, and ore deposit data from the U.S. Geological Survey-led assessment of 26 porphyry belts identified in the central Tethys region of Turkey, the Caucasus, Iran, western Pakistan, and southern Afghanistan relate porphyry mineralization to the tectonomagmatic evolution of the region and associated subduction and postsubduction processes...
Authors
Lukas Zürcher, Jane M. Hammarstrom, John C. Mars, Stephen Ludington, Michael L. Zientek
Porphyry copper assessment of the Tethys region of western and southern Asia: Chapter V in Global mineral resource assessment
A probabilistic mineral resource assessment of undiscovered resources in porphyry copper deposits in the Tethys region of western and southern Asia was carried out as part of a global mineral resource assessment led by the U.S. Geological Survey (USGS). The purpose of the study was to delineate geographic areas as permissive tracts for the occurrence of porphyry copper deposits at a...
Authors
Lukas Zürcher, Arthur A. Bookstrom, Jane M. Hammarstrom, John C. Mars, Stephen Ludington, Michael L. Zientek, Pamela Dunlap, John C. Wallis, Lawrence Drew, David M. Sutphin, Byron R. Berger, Richard J. Herrington, Mario Billa, Ilkay Kuşcu, Charles J. Moon, Jeremy P. Richards
By
Energy and Mineral Resources Mission Area, Energy Resources Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Energy & Minerals Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Porphyry copper assessment of northeast Asia: Far East Russia and northeasternmost China: Chapter W in Global mineral resource assessment
The U.S. Geological Survey assesses resources (mineral, energy, water, environmental, and biologic) at regional, national, and global scales to provide science in support of land management and decision making. Mineral resource assessments provide a synthesis of available information about where mineral deposits are known and suspected to be in the Earth’s crust, which commodities may be...
Authors
Mark J. Mihalasky, Stephen Ludington, Dmitriy V. Alexeiev, Thomas P. Frost, Thomas D. Light, Deborah A. Briggs, Jane M. Hammarstrom, John C. Wallis, Arthur A. Bookstrom, Andre Panteleyev
Porphyry copper assessment of the Central Asian Orogenic Belt and eastern Tethysides: China, Mongolia, Russia, Pakistan, Kazakhstan, Tajikistan, and India: Chapter X in Global mineral resource assessment
The U.S. Geological Survey collaborated with international colleagues to assess undiscovered resources in porphyry copper deposits in the Central Asian Orogenic Belt and eastern Tethysides. These areas host 20 known porphyry copper deposits, including the world class Oyu Tolgoi deposit in Mongolia that was discovered in the late 1990s. The study area covers major parts of the world’s...
Authors
Mark J. Mihalasky, Stephen Ludington, Jane M. Hammarstrom, Dmitriy V. Alexeiev, Thomas P. Frost, Thomas D. Light, Gilpin Robinson, Deborah A. Briggs, John C. Wallis, Robert J. Miller, Arthur A. Bookstrom, Andre Panteleyev, Andre Chitalin, Reimar Seltmann, Yan Guangsheng, Lian Changyun, Mao Jingwen, Li Jinyi, Xiao Keyan, Qiu Ruizhao, Shao Jianbao, Shai Gangyi, Du Yuliang
By
Energy and Mineral Resources Mission Area, Energy Resources Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Energy & Minerals Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Potash: a global overview of evaporate-related potash resources, including spatial databases of deposits, occurrences, and permissive tracts
Potash is mined worldwide to provide potassium, an essential nutrient for food crops. Evaporite-hosted potash deposits are the largest source of salts that contain potassium in water-soluble form, including potassium chloride, potassium-magnesium chloride, potassium sulfate, and potassium nitrate. Thick sections of evaporitic salt that form laterally continuous strata in sedimentary...
Authors
Greta J. Orris, Mark D. Cocker, Pamela Dunlap, Jeff Wynn, Gregory T. Spanski, Deborah A. Briggs, Leila Gass, James D. Bliss, Karen Sue Bolm, Chao Yang, Bruce R. Lipin, Stephen Ludington, Robert J. Miller, Mirosław Słowakiewicz
By
Energy and Mineral Resources Mission Area, Energy Resources Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Energy & Minerals Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Porphyry copper assessment of East and Southeast Asia: Philippines, Taiwan (Republic of China), Republic of Korea (South Korea), and Japan
The U.S. Geological Survey collaborated with member countries of the Coordinating Committee for Geoscience Programmes in East and Southeast Asia (CCOP) on an assessment of the porphyry copper resources of East and Southeast Asia as part of a global mineral resource assessment. The assessment covers the Philippines in Southeast Asia, and the Republic of Korea (South Korea), Taiwan...
Authors
Jane M. Hammarstrom, Arthur A. Bookstrom, Michael W. Demarr, Connie Dicken, Stephen Ludington, Gilpin Robinson, Michael L. Zientek