Michael Cosca
Biography
Michael Cosca is a research geologist with the U.S. Geological Survey, who combines 40Ar/39Ar geochronology with mineralogy, petrology, and field geology to understand igneous, metamorphic, and tectonic processes at the regional, local, and sub-grain scale. Mike received his undergraduate degree in geology from the University of California, Berkeley (1981) and M.Sc. (1985) and Ph.D. (1989) in geology from the University of Michigan, Ann Arbor. After completing his Ph.D., he moved to Switzerland and for nearly 19 years conducted scientific research at the University of Lausanne. During this time he constructed a 40Ar/39Ar research laboratory and obtained research funding that supported 4 Ph.D. students, 2 M.Sc. students and 2 post-doctoral scholars and worked closely with colleagues from Lausanne. This research was funded primarily with grants he obtained from the Swiss National Science Foundation with additional support from the University of Lausanne.
Mike joined the U.S Geological Survey in 2008 and supervises the 40Ar/39Ar geochronology laboratory in Denver. His research is broadly focused on understanding the geochronology of ore deposits, mountain building, volcanic stratigraphy, landscape formation, near-surface faulting, physical and chemical controls of argon distribution in minerals and rocks, and developing novel methods for 40Ar/39Ar analysis. Much of his research involves collaborations with USGS scientists from the Geology, Geophysics, and Geochemistry Science Center and the Geosciences and Environmental Change Science Center. Current research projects include the Cenozoic landscape evolution of the Southern Rocky Mountains, igneous activity related to mineralization in the Basin and Range province, and the timing of fluid flow and mineralization in the Proterozoic mid continent rift of North America.
Publications
Buchs, D., Pilet, S., Baumgartner, P., Cosca, M., Flores, K., and Bandini, A., 2013, Low-volume intraplate volcanism in the Early/Middle Jurassic Pacific basin documented by accreted sequences in Costa Rica: Geology, Geophysics, Geosystems (G3), v. 14, p. 1552-1568.
Lüdecke, T., Mikes, T., Rojay, F.B., Cosca, M., and Mulch, A., 2013, Stable isotope-based reconstruction of Oligo-Miocene paleoenvironment and paleohydrology of Central Anatolian lake basins (Turkey): Turkish Journal of Earth Sciences, v. 22, p. 793-819.
Farmer, G.L., Glazner, A.F., Kortmeier, W.T., Cosca, M.A., Jones, C.H., Moore, J.E., and Schweickert, R.A., 2013, Mantle lithosphere as a source of postsubduction magmatism, northern Sierra Nevada, California: Geosphere, v. 9, p. 1102-1124.
Idleman, L., Cosca, M.A., Heizler, M.T., Thomson, S.N., Teyssier, C., Whitney, D.L., 2014, Tectonic burial and exhumation cycles tracked by muscovite and K-feldspar 40Ar/39Ar thermochronology in a strike-slip fault zone, central Turkey: Tectonophysics, v. 612-613, p. 134-146.
Science and Products
Argon Geochronology
This project supports the USGS argon geochronology laboratory in Denver. The USGS 40Ar/39Ar geochronology laboratory is a state-of-the-art research facility for determining absolute ages of minerals and rocks. The 40Ar/39Ar laboratory contributes critical geochronology to individual USGS research projects and to partners in academia and other Federal...
Serving the U.S. Geological Survey’s geochronological data
Geochronological data provide essential information necessary for understanding the timing of geologic processes and events, as well as quantifying rates and timescales key to geologic mapping, mineral and energy resource and hazard assessments. The USGS’s National Geochronological Database (NGDB) contains over 30,000 radiometric ages, but no formal update has occurred in over 20 years. This...
Geochronologic Investigations
The present landscape of the Southern Rocky Mountains and surrounding physiographic areas results from time-integrated interaction between the asthenosphere, lithosphere, and hydrosphere. Large-scale phenomena, such as asthenospheric upwelling directly or indirectly affect lithospheric thinning, faulting, basin development, and igneous activity sometimes associated with ore deposits. During...
Data to accompany U.S. Geological Survey Data Series 1099: Petrographic, geochemical and geochronologic data for Cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
This dataset is the assembled analytical results of geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada. Much of the data presented here for the Tonopah and Divide districts are for samples collected by Bonham and Garside (1979) du
U-Pb SHRIMP and 40Ar/39Ar geochronologic data and backscatter electron (BSE) and panchromatic cathodoluminescent (CL) imagery of sample materials for study of dikes, country rock, and alteration systems, Butte, U.S.A.
These data are for a multidisciplinary study of dikes, country rock, and alteration systems, Butte, U.S.A. Results of the study are described and interpreted in Lund and others (2018). Data included are U-Pb sensitive high-resolution ion microprobe (SHRIMP) geochronology for quartz porphyry dikes, 40Ar/39Ar thermochronologic data for biotite, hornblende, and K-feldspar fro
Argon geochronology data from the Austroalpine-Pennine boundary, Central Alps, Switzerland
Ar/Ar data are reported from eight samples of white mica separated from rock samples collected along the Austroalpine-Pennine boundary in the Central Alps of Switzerland. These samples were collected as part of a PhD study to examine the tectonic history of this boundary and these argon geochronology data represent one small part of the study. Data are reported from these eight samples...
Data release of geospatial map database, argon geochronology and geochemistry data for: Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado
This dataset accompanies publication "Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado". Data presented here include the digital geologic database, 40Ar/39Ar geochronology and major and trace element chemistry from lava flows and an ignimbrite. The geologic database includes spatial feature classes and non-spatial tables that collectively contain
Data release for the geologic map of the upper Arkansas River valley region, north-central Colorado
This 1:50,000-scale geologic map represents a compilation of the most recent geologic studies of the upper Arkansas River valley, between Leadville and Salida, Colorado. The valley is structurally controlled by an extensional fault system that forms part of the prominent northern Rio Grande rift, an intra-continental region of crustal extension. This work also incorporates new detailed
Age and mantle sources of Quaternary basalts associated with “leaky” transform faults of the migrating Anatolia-Arabia-Africa triple junction
The Anatolia (Eurasia), Arabia, and Africa tectonic plates intersect in southeast Turkey, near the Gulf of İskenderun, forming a tectonically active and unstable triple junction (the A3 triple junction). The plate boundaries are marked by broad zones of major, dominantly left-lateral transform faults including the East Anatolian fault zone (...
Cosca, Michael; Reid, Mary; Delph, Jonathan; Gençalioğlu Kuşcu, Gonca; Blichert-Toft, Janne; Premo, Wayne R.; Whitney, Donna; Teyssier, Christian; Rojay, BoraCenozoic tectonic evolution of the Ecemiş fault zone and adjacent basins, central Anatolia, Turkey during the transition from Arabia - Eurasia collision to escape tectonics
The effects of Arabia-Eurasia collision are recorded in faults, basins, and exhumed metamorphic massifs across eastern and central Anatolia. These faults and basins also preserve evidence of major changes in deformation and associated sedimentary processes along major suture zones including the Inner Tauride suture where it lies along the southern...
Umhoefer, Paul J.; Thompson, Stuart; Lefebre, Come; Cosca, Michael; Teyssier, Christian; Whitney, Donna L.Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado
This report presents a 1:24,000-scale geologic map, cross sections, and descriptive and interpretative text for the Poncha Pass area in central Colorado. The map area is irregular in shape, covering all of one 7 ½' quadrangle (Poncha Pass) and parts of five others (Mount Ouray, Maysville, Salida West, Salida East, and Wellsville). The map...
Minor, Scott A.; Caine, Jonathan Saul; Ruleman, Chester A.; Fridrich, Christopher J.; Chan, Christine F.; Brandt, Theodore R.; Holm-Denoma, Christopher S.; Morgan, Leah E.; Cosca, Michael A.; Grauch, V. J.Petrology of volcanic rocks associated with silver-gold (Ag-Au) epithermal deposits in the Tonopah, Divide, and Goldfield Mining Districts, Nevada
Miocene calc-alkaline volcanic rocks, part of the southern segment of the ancestral Cascades magmatic arc, are spatially, temporally, and likely genetically associated with precious metal epithermal deposits in the Tonopah, Divide, and Goldfield Districts of west-central Nevada. In the Tonopah mining district, volcanic rocks include the Mizpah...
du Bray, Edward A.; John, David A.; Colgan, Joseph P.; Vikre, Peter G.; Cosca, Michael A.; Morgan, Leah E.Petrographic, geochemical, and geochronologic data for cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
The purpose of this report is to summarize geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada (fig. 1). Much of the data presented here for the Tonopah and Divide districts are for samples...
du Bray, Edward A.; John, David A.; Vikre, Peter G.; Colgan, Joseph P.; Cosca, Michael A.; Morgan, Leah E.; Fleck, Robert J.; Premo, Wayne R.; Holm-Denoma, Christopher S.A supervolcano and its sidekicks: A 100 ka eruptive chronology of the Fish Canyon Tuff and associated units of the La Garita magmatic system
Establishing temporal constrains on major volcanic eruptions is limited by the precision of existing geochronometers. Prior work on the La Garita caldera, created by the eruption of the Fish Canyon Tuff, failed to resolve temporal differences between pre-, syn-, and post-collapse eruptive units. Here, we report 40Ar/39Ar geochronologic data...
Morgan, Leah E.; Johnstone, Samuel A.; Gilmer, Amy K.; Cosca, Michael A.; Thompson, Ren A.C–O stable isotope geochemistry and 40Ar/39Ar geochronology of the Bear Lodge carbonatite stockwork, Wyoming, USA
The carbonatite dike swarm and vein stockwork at the center of the Paleogene Bear Lodge alkaline complex (BLAC), Wyoming, USA, is host to diverse REE mineral assemblages that are largely a result of subsolidus modification and REE redistribution. Pseudomorphic replacement of primary burbankite by an assemblage of...
Andersen, Allen; Larson, Peter B.; Cosca, Michael A.Two-event lode-ore deposition at Butte, USA: 40Ar/39Ar and U-Pb documentation of Ag-Au-polymetallic lodes overprinted by younger stockwork Cu-Mo ores and penecontemporaneous Cu lodes
The ore-genesis model for world-class deposits of the Butte mining district, Montana, USA, is deep pre-Main Stage porphyry Cu-Mo and overlying Main Stage Ag-Zn-Cu zoned-lode deposits, both of which formed from hydrothermal fluids driven by minor volumes of rhyolitic magma. The lode-specific model is that hydrothermal processes diminished in...
Lund, Karen; McAleer, Ryan J.; Aleinikoff, John N.; Cosca, Michael A.; Kunk, Michael J.Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado
The geologic map of the San Antonio Mountain area in northern New Mexico and southern Colorado is located along the west-central part of the San Luis Valley. The San Luis Valley is the geomorphic expression of the San Luis Basin, an extensional basin associated with the northern Rio Grande rift. Deposits within the map area record volcanic,...
Turner, Kenzie J.; Thompson, Ren A.; Cosca, Michael A.; Shroba, Ralph R.; Chan, Christine F.; Morgan, Leah E.Rapid late Miocene surface uplift of the Central Anatolian Plateau margin
The Central Anatolian Plateau (CAP), Turkey, is bordered to its south by a steep mountain belt that emerged ∼8–7 Ma ago from the Mediterranean Sea. Knowledge of the onset, duration and rate of surface uplift and orographic barrier formation along the plateau margin is crucial for understanding the geodynamic drivers of plateau uplift. We...
Meijers, Maud J.M.; Brocard, Gilles Y.; Cosca, Michael A.; Lüdecke, Tina; Teyssier, Christian; Whitney, Donna L.; Mulch, AndreasClimate stability in Central Anatolia during the Messinian Salinity Crisis
Deposition of large amounts of evaporites and erosion of deep canyons within the Mediterranean Basin as a result of reduced basin connectivity with the Atlantic Ocean and the epicontinental Paratethys Sea characterized the Messinian Salinity Crisis (MSC, 5.97–5.33 Ma). The influence of the MSC on Mediterranean environmental conditions...
Meijers, Maud J.M.; Peynircioğlu, Ahmet A; Cosca, Michael A.; Brocard, Gilles Y.; Whitney, Donna L.; Langereis, Cor G.; Mulch, AndreasThermochronometry across the Austroalpine-Pennine boundary, Central Alps, Switzerland: Orogen-perpendicular normal fault slip on a major ‘overthrust’ and its implications for orogenesis
Fifty‐one new and 309 published thermochronometric ages (nine systems with closure temperatures ranging from ~450 to 70°C) from the Graubünden region of the Central Alps demonstrate that a pronounced thermal mismatch between the Austroalpine allochthon (Alpine “orogenic lid”) and the Pennine zone persisted until at least 29 Ma and, allowably...
Price, Jason B.; Wernicke, Brian P.; Cosca, Michael A.; Farley, Kenneth A.