Michael L. Zientek is a research geologist at the Geology, Minerals, Energy, and Geophysics Science Center. He received a PhD degree in geology from Stanford and a BS degree in geology from the University of Texas. Since joining the USGS in 1983, Michael has devoted his career to studying economic geology and mineral resource assessments and specializes in magmatic ore deposits.
Mike is an economic geologist who works at the USGS Spokane Office, Spokane, Washington. He provides expertise in economic geology, assessment methods, and analysis of global, national, and regional datasets needed to plan, conduct and direct research on a broad range of land-use and mineral-resource-related issues.
His recent resource assessment work includes the SaMiRA assessment for the BLM and the USGS Global Mineral Resource Assessment project.
Mike's research interests include the origin of magmatic ore deposits enriched in platinum-group elements, chromium, and nickel. As part of that effort, he organized and coordinated International Geological Correlation Programme Project 336 from 1992 to 1996, conducted topical studies on the Stillwater Complex in Montana and the Duluth Complex, Minnesota, and worked on projects in Albania, Russia, and Indonesia. He was the Scientist-in-Charge of the Spokane Field Office from 1994 to 1998.
Education and Certifications
PhD, Stanford University
BS, University of Texas
Science and Products
Geophysical Studies on the Architecture of Large Igneous Systems Hosting Magmatic Ore Deposits
Mineral Resource Assessment Training
Platinum-Group Elements in Layered Intrusions Associated with the Midcontinent Rift
Critical commodity studies, Stillwater Complex, Montana and Duluth Complex, Minnesota
Databases and Information Analysis
Global Mineral Resource Assessments
Headwaters Province - Idaho and Montana: Earth Science Studies in Support of Public Policy Development and Land Stewardship
Stillwater Complex, Montana—logs of core drilled by Stillwater Mining Company and Anaconda Copper Corp. in the Stillwater Mine area, 1983 to 1989
Surfaces representing the basal mineralized zone in the South Kawishiwi, Bathtub, and Partridge River Intrusions, Duluth Complex, Minnesota
Stillwater Complex, Montana: Logs of core drilled by Chrome Corporation of America in the Mountain View area, 1988 to 1990
Structural measurements and their calculated surface traces, South Kawishiwi area, Duluth Complex, Minnesota
Geochemistry of rocks and rock fabric data near the hanging wall contact to the Reef Package, Stillwater Complex, Montana, USA
Thin section images of hand samples from the Crocodile Lake and Cucumber Lake Intrusions, Duluth Complex, Minnesota
Thin section images of drill core and hand samples from the South Kawishiwi Intrusion, Duluth Complex, Minnesota
Thin section images of drill core and hand samples from the Stillwater Mine area, Stillwater Complex, Montana
Thin section images of xenoliths from north of the Stillwater Complex, Montana
Stillwater Complex, Montana: Logs of core drilled by Anaconda in the Nye Basin area, 1968 to 1982
Thin section images of drill core from the Chrome Lake area in the Stillwater Complex, Montana
Thin section images of AMAX drill core from the Stillwater Complex, Montana
Electromagnetic and magnetic imaging of the Stillwater Complex, Montana, USA
A novel origin for PGE reefs: A case study of the J-M Reef
The geochemical and textural transition between the Reef Package and its hanging wall, Stillwater Complex, Montana, USA
Origin of the J-M Reef and Lower Banded series, Stillwater Complex, Montana, USA
Mineral deposit discovery order and three-part quantitative assessments
The nature and composition of the J-M Reef, Stillwater Complex, Montana, USA
Grade and tonnage model for tungsten skarn deposits—2020 update
Mapping the 3-D extent of the Stillwater Complex, Montana—Implications for potential platinum group element exploration and development
Tectono-magmatic evolution of porphyry belts in the central Tethys region of Turkey, the Caucasus, Iran, western Pakistan, and southern Afghanistan
Assessment of undiscovered copper resources of the world, 2015
Platinum-group elements
The platinum-group elements (PGEs)—platinum, palladium, rhodium, ruthenium, iridium, and osmium—are metals that have similar physical and chemical properties and tend to occur together in nature. PGEs are indispensable to many industrial applications but are mined in only a few places. The availability and accessibility of PGEs could be disrupted by economic, environmental, political, and social e
Cobalt—Styles of deposits and the search for primary deposits
Science and Products
- Science
Geophysical Studies on the Architecture of Large Igneous Systems Hosting Magmatic Ore Deposits
Platinum group elements, also known as PGEs, are a group of elements that have specific properties which make them useful for various applications in industry. One geologic setting that contains large concentrations of platinum group elements is layered mafic intrusions. This project will use new and preexisting geophysical datasets to characterize the internal structure of layered intrusions...Mineral Resource Assessment Training
The USGS Mineral Resources Program conducts mineral resource assessments and is training USGS scientists in how to conduct these assessments for future work. As a practical exercise, the scientists will conduct an assessment for tungsten in the U.S.Platinum-Group Elements in Layered Intrusions Associated with the Midcontinent Rift
Platinum-group elements (PGE) are critical commodities. They are essential for the U.S. economy; however the U.S. imports about 90 percent of the platinum-group elements that we need to use. The project objective is to assess the Duluth Complex and related mafic-ultramafic intrusions in the 1.1 Ga Midcontinent Rift System in the Lake Superior region. Our current activities focus on a Keweenawan...Critical commodity studies, Stillwater Complex, Montana and Duluth Complex, Minnesota
Scientific research can make our resource assessments of critical minerals more effective. This project focuses on the Stillwater Complex, Montana, which has rocks enriched in platinum-group elements (PGE), chromium, cobalt, and nickel. Project objectives are to update databases, evaluate new mapping techniques, document new styles of mineralization, and document and support research on the...Databases and Information Analysis
Our objectives are to: 1) collect and assimilate digital geospatial data in a standardized format for minerals-related research and assessments, 2) develop and improve analytical procedures for using geospatial data in minerals products, 3) provide support for timely, quality, and reproducible mineral assessments, 4) provide easy access to the data, and 5) report results of our work in a digital...Global Mineral Resource Assessments
In response to the growing demand for information on the global mineral-resource base, the U.S. Geological Survey (USGS) completed assessments for undiscovered resources of porphyry and sediment-hosted copper, platinum-group elements, and potash.Headwaters Province - Idaho and Montana: Earth Science Studies in Support of Public Policy Development and Land Stewardship
The Headwaters Province project provided geoscience data and interpretations to the Federal Land Management Agencies (FLMA) that were basic to sound policy and land-stewardship practices. - Data
Filter Total Items: 24
Stillwater Complex, Montana—logs of core drilled by Stillwater Mining Company and Anaconda Copper Corp. in the Stillwater Mine area, 1983 to 1989
This dataset includes TIFF (Tagged Image File Format) images of graphic drill core logs showing associated drill core information, a TIFF image of the explanation for the lithology and structure sections of the logs, an Esri shapefile of the locations of the drill holes, and 12 .csv files of tabular data that were compiled from handwritten drill core logs. The drill core is from the Stillwater MinSurfaces representing the basal mineralized zone in the South Kawishiwi, Bathtub, and Partridge River Intrusions, Duluth Complex, Minnesota
This dataset includes five Esri grids representing the copper-nickel-platinum group element (Cu-Ni-PGE) mineralized zone found in the South Kawishiwi, Bathtub, and Partridge River intrusions, Duluth Complex, Minnesota. The data are also presented in .csv format to provide an open-source file type. We are using the term "basal mineralized zone" (bmz) as an informal term representing the mineralizedStillwater Complex, Montana: Logs of core drilled by Chrome Corporation of America in the Mountain View area, 1988 to 1990
This dataset includes TIFF (Tagged Image File Format) images of graphic drill core logs showing associated drill core information, a TIFF image of the explanation for the lithology and structure sections of the logs, an Esri shapefile of the locations of the drill holes, and 17 individual .csv files of tabular data that were compiled from handwritten drill core logs. The drill core is from the MouStructural measurements and their calculated surface traces, South Kawishiwi area, Duluth Complex, Minnesota
This dataset includes a point shapefile representing structural measurements taken from a study area near the South Kawishiwi Intrusion in the Duluth Complex, Minnesota and a line shapefile representing the surface traces of the structural measurements. The structural measurements point file consists of a compilation of data from multiple published and unpublished sources. The surface trace file wGeochemistry of rocks and rock fabric data near the hanging wall contact to the Reef Package, Stillwater Complex, Montana, USA
The Reef Package is a sequence of coarse-grained cumulates that host the J-M Reef Pd-Pt deposit in the Stillwater Complex of Montana. The top of the Reef Package marks the top of economic-grade platinum-group element mineralization and is identified by a distinct change in rock fabric, from the coarse-grained rocks of the Reef Package to finer-grained cumulates in the hanging wall. This dataset taThin section images of hand samples from the Crocodile Lake and Cucumber Lake Intrusions, Duluth Complex, Minnesota
This dataset includes photographic images of thin sections created from hand samples collected from the Crocodile Lake and Cucumber Lake Intrusions, Duluth Complex, Minnesota, along with a shapefile representing the locations of the samples. The samples were collected in order to define copper-nickel-platinum-group element resources associated with the Crocodile Lake and Cucumber Lake Intrusions iThin section images of drill core and hand samples from the South Kawishiwi Intrusion, Duluth Complex, Minnesota
This dataset includes photographic images of thin sections created from hand samples and drill core sourced from the South Kawishiwi Intrusion, Duluth Complex, Minnesota, along with two shapefiles representing the locations of the samples and drill hole collars. The samples were collected and core was drilled in order to define copper-nickel-platinum-group element resources associated with the SouThin section images of drill core and hand samples from the Stillwater Mine area, Stillwater Complex, Montana
This dataset includes photographic images of thin sections created from hand samples and drill core from the Stillwater Complex, Montana, along with a shapefile representing the locations of the underground samples and drill hole collars. The samples were collected and core was drilled in order to define platinum-group element resources associated with the J-M Reef at the Stillwater Mine in the StThin section images of xenoliths from north of the Stillwater Complex, Montana
This dataset includes photographic images of thin sections made from xenolith samples collected from the Sliderock Mountain and Susie Peak plutons, Montana, along with a shapefile representing the locations of the samples. The plutons are located north of the Stillwater Complex, Montana, which is exposed along the northern side of the Beartooth Mountains in Montana. To the north of the StillwaterStillwater Complex, Montana: Logs of core drilled by Anaconda in the Nye Basin area, 1968 to 1982
This dataset includes TIFF (Tagged Image File Format) images of graphic drill core logs showing associated drill core information, a TIFF image of the explanation for the lithology and structure sections of the logs, an Esri shapefile of the locations of the drill holes, and fourteen individual .csv files of tabular data that were compiled from handwritten drill core logs. The drill core is from tThin section images of drill core from the Chrome Lake area in the Stillwater Complex, Montana
This dataset includes photographic images of thin sections of drill core from the Stillwater Complex, Montana, along with a shapefile representing the locations of the drill holes. The core was drilled in order to study contact-type copper and nickel sulfide mineralization in the Stillwater Complex. The images of the entire thin section, both in plane- and cross-polarized light, were taken using aThin section images of AMAX drill core from the Stillwater Complex, Montana
This dataset includes photographic and micrographic images of thin sections of drill core from the Stillwater Complex, Montana, along with a shapefile representing the locations of the drill holes. The core was drilled in order to study contact-type copper and nickel sulfide mineralization in the Stillwater Complex. See data release https://doi.org/10.5066/p9w5kp8u for accompanying drill log data. - Publications
Filter Total Items: 65
Electromagnetic and magnetic imaging of the Stillwater Complex, Montana, USA
Modelling and analysis of helicopter electromagnetic data result in resistivity and susceptibility models and derivatives of magnetic data that characterise shallow parts of the Stillwater Complex, critical for aiding exploration and expansion of globally scarce critical and battery mineral resources that include platinum group elements, nickel, copper and chromium. The magnetic susceptibly modelsAuthorsCarol A. Finn, Michael L. Zientek, Benjamin r. Bloss, Heather L. Parks, Justin ModrooA novel origin for PGE reefs: A case study of the J-M Reef
The origin of meter scale stratiform layers of disseminated sulfides in enriched platinum group element (PGE) tenors and grades, called reef-type deposits, are the world’s most significant source of PGEs. Their origin in layered mafic intrusions remains debated, but in general, most researchers favor an orthomagmatic origin for reef-type deposits and agree that their formation requires the equilibAuthorsMichael Jenkins, James E. Mungall, Michael L. Zientek, Gelu Costin, Zhuo-sen YaoThe geochemical and textural transition between the Reef Package and its hanging wall, Stillwater Complex, Montana, USA
The highest grade Pd-Pt deposit on Earth, the J-M Reef, is hosted in coarse-grained to pegmatoidal cumulates called the Reef Package. Decades of mine development of the J-M Reef have revealed that a distinct discontinuity in rock fabric marks the top of the rock unit that hosts economic-grade sulfide mineralization. Mine geologists refer to this discontinuity as the hanging wall contact. This contAuthorsM. Christopher Jenkins, James E. Mungall, Michael L. Zientek, Kevin Butak, Sam R. Corson, Paul Holick, Ryan McKinley, Heather A. LowersOrigin of the J-M Reef and Lower Banded series, Stillwater Complex, Montana, USA
The origin and parental magma for layered cumulates in the Lower Banded series (LBS) and the J-M Reef Pd-Pt deposit of the Stillwater Complex remains poorly constrained. We present whole-rock lithogeochemistry and mineral chemistry from LBS rocks collected from drill holes and surface samples from the Mountain View area of the complex that in total span nearly the entirety of the LBS stratigraphy.AuthorsMichael Jenkins, James E. Mungall, Michael L. Zientek, Gelu Costin, Zhuo-sen YaoMineral deposit discovery order and three-part quantitative assessments
Larger oil pools tending to be discovered earlier in an exploration play suggests the same pattern might exist for mineral deposits and could be used in predicting sizes of undiscovered deposits in mineral assessments. The volume of individual petroleum pools is highly correlated with surface projection area of pools in basins. The gradual additions to individual oil pool reserves over time adds tAuthorsDonald A. Singer, Michael L. ZientekThe nature and composition of the J-M Reef, Stillwater Complex, Montana, USA
In this contribution, we analyze 30 years of mine development data and quantitatively identify the processes that control the grade and tenor of the mineralized rock. An assay database of more than 60,000 samples was used to examine variations in ore grade and tenor of the sulfide mineralization in the J-M reef horizon of the Stillwater Complex along the strike and down the dip of the deposit in tAuthorsMichael Jenkins, James E. Mungall, Michael L. Zientek, Paul Holick, Kevin ButakGrade and tonnage model for tungsten skarn deposits—2020 update
This report presents an updated grade and tonnage model for tungsten skarn deposits. As a critical component of the U.S. Geological Survey’s three-part form of quantitative mineral resource assessment, robust grade and tonnage models are essential to transforming mineral resource assessments into effective tools for decision makers. Using the best data available at the time of publication, this reAuthorsCarlin J. Green, Graham W. Lederer, Heather L. Parks, Michael L. ZientekMapping the 3-D extent of the Stillwater Complex, Montana—Implications for potential platinum group element exploration and development
Geophysical models characterize the exposed and interpreted buried extent of the Stillwater Complex, critical for understanding the origin of the layered mafic intrusion and its associated high-grade platinum group element resources. The 3D models, constrained by gravity, magnetic, xenolith, seismic, borehole, and rock property data indicate that the likely maximum extent of the Stillwater ComplexAuthorsCarol A. Finn, Michael L. Zientek, Heather L. Parks, Dana E. PetersonTectono-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, Cevizlidere, TegAuthorsLukas Zürcher, Arthur A. Bookstrom, Jane M. Hammarstrom, John C. Mars, Stephen Ludington, Michael L. Zientek, Pamela Dunlap, John WallisAssessment of undiscovered copper resources of the world, 2015
The U.S. Geological Survey completed the first-ever global assessment of undiscovered copper resources for the two most significant sources of global copper supply: porphyry copper deposits and sediment-hosted stratabound copper deposits. The geology-based study identified 236 areas for undiscovered copper in 11 regions of the world. Estimated amounts of undiscovered copper resources are reportedAuthorsJane M. Hammarstrom, Michael L. Zientek, Heather L. Parks, Connie L. DickenPlatinum-group elements
The platinum-group elements (PGEs)—platinum, palladium, rhodium, ruthenium, iridium, and osmium—are metals that have similar physical and chemical properties and tend to occur together in nature. PGEs are indispensable to many industrial applications but are mined in only a few places. The availability and accessibility of PGEs could be disrupted by economic, environmental, political, and social e
AuthorsMichael L. Zientek, Patricia J. Loferski, Heather L. Parks, Ruth F. Schulte, Robert R. SealCobalt—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 contains signifiAuthorsMurray W. Hitzman, Arthur A. Bookstrom, John F. Slack, Michael L. Zientek - News