Mitchell Bennett is a Geologist at the U.S. Geological Survey in Denver, CO. He assists with melt and fluid inclusion petrography and analysis in the Denver Inclusion Analysis Laboratory. At present he aids in the study of ore-forming hydrothermal fluids encountered in the Yellow Pine Au-Sb-W deposit in Idaho and in IOA-IOCG deposits in SE Missouri.
Mitchell runs and maintains the USGS Experimental Petrology Lab's cold-seal pressure vessels used in high temperature melt and fluid inclusion experiments.
Prior to joining the USGS, Mitchell worked as an intern at the National Renewable Energy Laboratory (NREL) within the Technology Systems and Sustainability Analysis Group in Golden, CO, where he provided research support during development of NREL’s Open Energy Information (OpenEI) website. As a part of this work he prepared case study reports on active and producing geothermal resource areas and worked with a team of geologists and developers to construct a comprehensive database of geothermal exploration efforts used to define different geothermal prospects throughout the United States.
During his M.Sc. research he used fluid inclusion and cathodoluminescence petrography to study multi-stage vein quartz from a range of different porphyry deposit classes, including those at Far Southeast in the Philippines, Butte in Montana, Bingham Canyon in Utah, and in the Maricunga Belt in Chile. He examined how these characteristics relate to vein-scale processes associated with ore mineral deposition and emplacement depth within the larger context of the parent hydrothermal systems. Based on these investigations he developed new laboratory preparation and analytical procedures that utilize simple petrographic techniques to identify transported porphyry quartz grains in fluvial sands, to be implemented in conjunction with routine geochemical surveys as a new exploration technique for porphyry deposits. His areas of expertise include: fluid inclusion petrography and microthermometry, cathodoluminescence petrography, melt inclusion analysis, ore deposits, and geothermal systems.
Science and Products
Mineral Resource Assessment Training
Trace element chemistry of sulfides and quartz, in situ sulfur isotope values of sulfides, cathodoluminescence of quartz, fluid inclusion microthermometry and raman, and radiogenic isotope and whole rock geochemistry from the Stibnite-Yellow Pine district
Spatial data associated with tungsten skarn resource assessment of the Northern Rocky Mountains, Montana and Idaho
Global Geochemical Database for Critical Minerals in Archived Mine Samples
Tungsten resources of the northern Rocky Mountains, Montana and Idaho— A synthesis and quantitative assessment of skarn-hosted resources
Quartz solubility in the H2O-NaCl system: A framework for understanding vein formation in porphyry copper deposits
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
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. - Data
Trace element chemistry of sulfides and quartz, in situ sulfur isotope values of sulfides, cathodoluminescence of quartz, fluid inclusion microthermometry and raman, and radiogenic isotope and whole rock geochemistry from the Stibnite-Yellow Pine district
This dataset is a collection of geochemical data on samples from the Stibnite-Yellow Pine district of Idaho. The datasets include: whole rock geochemistry; lead, strontium and neodymium isotope chemistry of sulfides and whole rock samples by isotope dilution-thermal-mass spectrometry (ID-TIMS); in situ sulfur isotope chemistry of sulfides by laser ablation-multi collector-inductively coupled-massSpatial data associated with tungsten skarn resource assessment of the Northern Rocky Mountains, Montana and Idaho
A mineral resource assessment was performed by the U.S. Geological Survey (USGS) to assess the potential of undiscovered skarn-hosted tungsten resources in the Northern Rocky Mountain region of eastern Idaho and western Montana. This region has seen moderate tungsten trioxide (WO3) production in the past from a variety of mineralization styles including skarn, vein and replacement, and wolframite-Global Geochemical Database for Critical Minerals in Archived Mine Samples
The Critical Minerals in Archived Mine Samples Database (CMDB) contains chemistry and geologic information for historic ore and ore-related rock samples from mineral deposits in the United States. In addition, the database contains samples from archetypal deposits from 27 other countries in North America, South America, Asia, Africa and Europe. Samples were obtained from archived ore collections u - Publications
Tungsten resources of the northern Rocky Mountains, Montana and Idaho— A synthesis and quantitative assessment of skarn-hosted resources
Mineral resource assessments performed by the U.S. Geological Survey provide a synthesis of available information about the location of known and suspected mineral deposits. This study focuses on skarn-hosted tungsten resources in the northern Rocky Mountain region of east-central Idaho and western Montana which have seen moderate tungsten trioxide production in the past from a variety of mineraliAuthorsAllen K. Andersen, Margaret A. Goldman, Mitchell M. Bennett, Connie L. Dicken, Philip J. Brown, Heather L. ParksQuartz solubility in the H2O-NaCl system: A framework for understanding vein formation in porphyry copper deposits
Porphyry copper deposits consist of low-grade stockwork and disseminated sulfide zones that contain characteristic vein generations formed during the evolution of the magmatic-hydrothermal systems. The present contribution proposes an interpretive framework for the formation of porphyry veins that is based on quartz solubility calculations in the H2O-NaCl system at temperatures of 100° to 1,000°CAuthorsThomas Monecke, Jochen Monecke, T James Reynolds, Subaru Tsuruoka, Mitchell M. Bennett, Wiley B Skewes, Richard M. PalinNon-USGS Publications**
Young, K.R., Witherbee, K., Levine, A., Keller, A., Balu, J., and Bennett, M., 2014. Geothermal Permitting and NEPA Timelines: Transactions - Geothermal Resources Council, GRC Annual Meeting 2014, Portland, Oregon, https://www.geothermal-library.org/index.php?mode=pubs&action=view&record=1033639.Young, K.R., Bennett, M., and Atkins, D., 2014. Geothermal Exploration Case Studies on OpenEI: Proceedings, Thirty-Ninth Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California, SGP–TR–202, https://pangea.stanford.edu/ERE/db/IGAstandard/record_detail.php?id=19918.Bennett, M., 2014. Cathodoluminescence and Fluid Inclusion Characteristics of Hydrothermal Quartz from Porphyry Deposits: M.Sc. Thesis, Colorado School of Mines, 157 p.Zhao, Xin-Fu, Zhou, Mei-Fu, Hitzman, M.W., Li, Jian-Wei, Bennett, M., Meighan, C., and Anderson, E., 2012. Late Paleoproterozoic to Early Mesoproterozoic Tangdan Sedimentary Rock-Hosted Strata-bound Copper Deposit, Yunnan Province, Southwest China: Economic Geology, v. 107, p. 357-375, https://doi.org/10.2113/econgeo.107.2.357.Easley, E., Garchar, L., Bennett, M., Morgan, P., and Wendlandt, R., 2011. A Geochemical and Isotopic Study of Two Geothermal Resources In the Rio Grande Rift, Colorado and New Mexico: The Mountain Geologist, v. 48, no. 4, p. 95-106, http://archives.datapages.com/data/mountain-geologist-rmag/data/048/048004/95_rmag-mg480095.htm.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.