Michael Cosca
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.
Science and Products
Thermochronometry across the Austroalpine-Pennine boundary, Central Alps, Switzerland: Orogen-perpendicular normal fault slip on a major ‘overthrust’ and its implications for orogenesis
Emergence and evolution of Santa Maria Island (Azores)—The conundrum of uplifted islands revisited
Episodic formation of the world-class Waihi epithermal Au-Ag vein system, Hauraki Goldfield, New Zealand
Preservation of ancient impact ages on the R chondrite parent body: 40Ar/39Ar age of hornblende-bearing R chondrite LAP 04840
Tracking the timing of subduction and exhumation using 40Ar/39Ar phengite ages in blueschist- and eclogite-facies rocks (Sivrihisar, Turkey)
U-Pb, Re-Os, and Ar/Ar geochronology of rare earth element (REE)-rich breccia pipes and associated host rocks from the Mesoproterozoic Pea Ridge Fe-REE-Au deposit, St. Francois Mountains, Missouri
Mid-Cretaceous oblique rifting of West Antarctica: Emplacement and rapid cooling of the Fosdick Mountains migmatite-cored gneiss dome
Himalayan gneiss dome formation in the middle crust and exhumation by normal faulting: New geochronology of Gianbul dome, northwestern India
The emergence of volcanic oceanic islands on a slow-moving plate: The example of Madeira Island, NE Atlantic
Application of U-Th-Pb phosphate geochronology to young orogenic gold deposits: New age constraints on the formation of the Grass Valley gold district, Sierra Foothills province, California
Pre-eruptive conditions of the Hideaway Park topaz rhyolite: Insights into metal source and evolution of magma parental to the Henderson porphyry molybdenum deposit, Colorado
Book review: Advances in 40Ar/39Ar dating: From archaeology to planetary sciences
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.
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Thermochronometry 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, until circa 18 Ma. The observed mismatch supports previAuthorsJason B. Price, Brian P. Wernicke, Michael A. Cosca, Kenneth A. FarleyEmergence and evolution of Santa Maria Island (Azores)—The conundrum of uplifted islands revisited
The growth and decay of ocean-island volcanoes are intrinsically linked to vertical movements. While the causes for subsidence are better understood, uplift mechanisms remain enigmatic. Santa Maria Island in the Azores Archipelago is an ocean-island volcano resting on top of young lithosphere, barely 480 km away from the Mid-Atlantic Ridge. Like most other Azorean islands, Santa Maria should be exAuthorsRicardo Ramalho, George Helffrich, Jose Madeira, Michael A. Cosca, Christine Thomas, Rui Quartau, Ana Hipolito, Alessio Rovere, Paul Hearty, Sergio AvilaEpisodic formation of the world-class Waihi epithermal Au-Ag vein system, Hauraki Goldfield, New Zealand
The world-class Waihi vein system in New Zealand has produced more than 248,400 kg Au and 1.43 million kg Ag. New high-precision 40Ar/39Ar dates of adularia from different veins show that some veins formed at different times (6.15 Ma Martha vs. 5.83 and 5.85 Ma Empire and Welcome, respectively), even though they have similar mineralogy. The Martha vein formed over a period of approximately 150,000AuthorsErin Gasston, Jeffrey L. Mauk, Michael A. Cosca, Leah E. Morgan, Chris M. HallPreservation of ancient impact ages on the R chondrite parent body: 40Ar/39Ar age of hornblende-bearing R chondrite LAP 04840
The hornblende- and biotite-bearing R chondrite LAP 04840 is a rare kind of meteorite possibly containing outer solar system water stored during metamorphism or postshock annealing deep within an asteroid. Because little is known regarding its age and origin, we determined 40Ar/39Ar ages on hornblende-rich separates of the meteorite, and obtained plateau ages of 4340(±40) to 4380(±30) Ma. These weAuthorsKevin Righter, Michael A. Cosca, Leah E. MorganTracking the timing of subduction and exhumation using 40Ar/39Ar phengite ages in blueschist- and eclogite-facies rocks (Sivrihisar, Turkey)
Geochronologic studies of high-pressure/low-temperature rocks can be used to determine the timing and rates of burial and exhumation in subduction zones by dating different stages of the pressure–temperature history. In this study, we present new in situ UV laser ablation 40Ar/39Ar phengite ages from a suite of lawsonite blueschist- and eclogite-facies rocks representing different protoliths (metaAuthorsKatherine F. Fornash, Michael A. Cosca, Donna L. WhitneyU-Pb, Re-Os, and Ar/Ar geochronology of rare earth element (REE)-rich breccia pipes and associated host rocks from the Mesoproterozoic Pea Ridge Fe-REE-Au deposit, St. Francois Mountains, Missouri
Rare earth element (REE)-rich breccia pipes (600,000 t @ 12% rare earth oxides) are preserved along the margins of the 136-million metric ton (Mt) Pea Ridge magnetite-apatite deposit, within Mesoproterozoic (~1.47 Ga) volcanic-plutonic rocks of the St. Francois Mountains terrane in southeastern Missouri, United States. The breccia pipes cut the rhyolite-hosted magnetite deposit and contain clastsAuthorsJohn N. Aleinikoff, David Selby, John F. Slack, Warren C. Day, Renee M. Pillers, Michael A. Cosca, Cheryl Seeger, C. Mark Fanning, Iain SamsonMid-Cretaceous oblique rifting of West Antarctica: Emplacement and rapid cooling of the Fosdick Mountains migmatite-cored gneiss dome
In Marie Byrd Land, West Antarctica, the Fosdick Mountains migmatite-cored gneiss dome was exhumed from mid- to lower middle crustal depths during the incipient stage of the West Antarctic Rift system in the mid-Cretaceous. Prior to and during exhumation, major crustal melting and deformation included transfer and emplacement of voluminous granitic material and numerous intrusions of mantle-deriveAuthorsRory McFadden, Christian Teyssier, Christine Siddoway, Michael A. Cosca, C. Mark FanningHimalayan gneiss dome formation in the middle crust and exhumation by normal faulting: New geochronology of Gianbul dome, northwestern India
A general lack of consensus about the origin of Himalayan gneiss domes hinders accurate thermomechanical modeling of the orogen. To test whether doming resulted from tectonic contraction (e.g., thrust duplex formation, antiformal bending above a thrust ramp, etc.), channel flow, or via the buoyant rise of anatectic melts, this study investigates the depth and timing of doming processes for GianbulAuthorsForrest Horton, Jeffrey Lee, Bradley Hacker, Meilani Bowman-Kamaha'o, Michael A. CoscaThe emergence of volcanic oceanic islands on a slow-moving plate: The example of Madeira Island, NE Atlantic
The transition from seamount to oceanic island typically involves surtseyan volcanism. However, the geological record at many islands in the NE Atlantic—all located within the slow-moving Nubian plate—does not exhibit evidence for an emergent surtseyan phase but rather an erosive unconformity between the submarine basement and the overlying subaerial shield sequences. This suggests that the transiAuthorsRicardo Ramalho, António Brum da Silveira, Paulo Fonseca, Jose Madeira, Michael A. Cosca, Mário Cachão, Maria M. Fonseca, Susana PradaApplication of U-Th-Pb phosphate geochronology to young orogenic gold deposits: New age constraints on the formation of the Grass Valley gold district, Sierra Foothills province, California
The Grass Valley orogenic gold district in the Sierra Nevada foothills province, central California, the largest historic gold producer of the North American Cordillera, comprises both steeply dipping east-west (E-W) veins located along lithologic contacts in accreted ca. 300 and 200 Ma oceanic rocks and shallowly dipping north-south (N-S) veins hosted by the Grass Valley granodiorite; the latterAuthorsRyan D. Taylor, Richard J. Goldfarb, Thomas Monecke, Ian R. Fletcher, Michael A. Cosca, Nigel M. KellyPre-eruptive conditions of the Hideaway Park topaz rhyolite: Insights into metal source and evolution of magma parental to the Henderson porphyry molybdenum deposit, Colorado
The Hideaway Park tuff is the only preserved extrusive volcanic unit related to the Red Mountain intrusive complex, which produced the world-class Henderson porphyry Mo deposit. Located within the Colorado Mineral Belt, USA, Henderson is the second largest Climax-type Mo deposit in the world, and is therefore an excellent location to investigate magmatic processes leading to Climax-type Mo mineralAuthorsCelestine N. Mercer, Albert H. Hofstra, Todor I. Todorov, Julie Roberge, Alain Burgisser, David T. Adams, Michael A. CoscaBook review: Advances in 40Ar/39Ar dating: From archaeology to planetary sciences
The recently published book Advances in 40Ar/39Ar Dating: From Archaeology to Planetary Sciences is a collection of 24 chapters authored by international scientists on topics ranging from decay constants to 40Ar/39Ar dating of extraterrestrial objects. As stated by the editors in their introduction, these chapters were assembled with the goal of providing technique-specific examples highlighting rAuthorsMichael A. CoscaNon-USGS Publications**
Mulch, A., Teyssier, C., Cosca, M A., and Chamberlain, C.P., 2007, Stable isotope paleoaltimetry of Eocene core complexes in the North American Cordillera, Tectonics, 26 (4), TC4001, doi:10.1029/2006TC00199.Zechmeister, M.S., Ferre, E., Cosca, M.A., Geissman, J.W., 2007, Slow and fast deformation in the Dora Maira Massif, Italian Alps: Pseudotachylytes and inferences on exhumation history. Journal of Stuctural Geology, 29 (7), p. 1114-1130, doi:10.1016/j.jsg.2007.03.009.Cosca, M. A., Giorgis, D., Rumble, D., and Liou, J. G. 2006, Limiting effects of UHP metamorphism on length scales of oxygen, hydrogen, and argon isotope exchange: an example from the Qinglongshan UHP ecologites, Sulu Terrain, China: In: Phase relations, high-pressure terranes, P-T-ometry, and plate pushing: a tribute to W. G. Ernst. International Book Series, v. 9, p. 290-323.Keane, S.D., DeWolf, C.P., Essene, E.J., Halliday, A.N., Hall, C.M., Cosca, M.A., 2006, Isotopic Constraints on the Thermal History of the Wind River Range, Wyoming: Implications for Archean Metamorphism. Canadian Journal of Earth Science, 43 (10), 1511-1532, doi:10.1139/e06-090.Manatschal, G., Engström, A., Desmurs, L., Schaltegger, U., Cosca, M., Müntener, O., Bernoulli, D., 2006, What is the tectono-metamorphic evolution of continental break-up: the example of the Tasna ocean-continent transistion. Journal of Structural Geology,28 (10), 1849-1869, doi:10.1016/j.jsg.2006.07.014.Mulch, A., Teyssier, C, Cosca, M.A, and Vennemann, T.W., 2006, Thermomechanical analysis of strain localization in a ductile detachment zone. Journal of Geophysical Research Solid Earth, 111 (B12), doi:10.1029/2005JB004032.Cosca, M.A., Caby, R., and Bussy, F., 2005, Geochemistry and 40Ar/39Ar geochronology of pseudotachylyte associated with UHP whiteschists from the Dora Maira massif, Italy. Tectonophysics, 402 (1-4), 93-110, doi:10.1016/j.tecto.2004.12.033.Cosca, M.A., Giorgis, D., Rumble, D., Liou, J.G., 2005, Limiting effects of UHP metamorphism on length-scales of oxygen, hydrogen, and argon isotope exchange: an example from the Qinglongshan UHP eclogites. International Geology Review, 47 (7), 716-749, doi:10.2747/0020-6814.47.7.716.Mulch, A., Cosca, M.A., Fiebig, J., and Andresen, A., 2005, Time scales of deformation and exhumation in extensional detachment systems determined by high-spatial resolution in situ UV-laser 40Ar/39Ar dating. Earth and Planetary Science Letters, 233 (3-4), 375-390, doi:10.1016/j.epsl.2005.01.042.Putlitz, B., Cosca, M.A., and Schumacher, J., 2005, Prograde mica 40Ar/39Ar growth ages recorded in high pressure rocks (Syros, Cyclades, Greece). Chemical Geology, 214 (1-2), 79-98, doi:10.1016/j.chemgeo.2004.08.056.Haeberlin, Y., Moritz, R., Fontboté, L., and Cosca, M., 2004, Carboniferous orogenic gold deposits at Pataz, Eastern Andean Cordillera, Peru: Geological and structural framework, paragenesis, alteration, and 40Ar/39Ar geochronology. Economic Geology, 99 (1), 73-112, doi:10.2113/gsecongeo.99.1.73.Mulch, A. and Cosca, M.A., 2004, Recrystallization or cooling ages? In situ UV-laser 40Ar/39Ar geochronology of muscovite in mylonitic rocks. Journal of the Geological Society of London, 161 (4), 573-582, doi:10.1144/0016-764903-110.Mulch, A., Teyssier, C., Cosca, M.A., Vanderhaeghe, O., and Vennemann, T., 2004, Reconstructing paleoelevation in eroded orogens. Geology, 32 (6), 525-528, doi:10.1130/G20394.1.Vannay, J-C., Grasemann, B., Rahn, M., Frank, W., Carter, A., Baudraz, V., Cosca, M., 2004, Miocene to Holocene exhumation of metamorphic crustal wedges in the NW Himalaya: evidence for tectonic extrusion coupled to fluvial erosion. Tectonics, 23 (1), doi:10.1029/2002TC001429.Winer, G.S., Feeley, T.C., and Cosca, M.A., 2004, Basaltic volcanism in the Bering Sea: geochronology and volcanic evolution of St. Paul Island, Pribilof Islands, Alaska. Journal of Volcanology and Geothermal Research, 134 (4), 277-301, doi:10.1016/j.jvolgeores.2004.02.003.Bendezú, R., Fontbonté, L., Cosca, M., 2003, Relative age of Cordilleran base metal lode and replacement deposits, and high sulfidation Au-(Ag) epithermal mineralization in the Colquijirca district, central Peru. Mineralium Deposita, 38, 683-694, doi:10.1007/s00126-003-0358-z.Camprubí, A., Ferrari, L., Cosca, M.A., Cardellach, E., Canals, A., 2003, Ages of epithermal deposits in Mexico: regional significance and links with the evolution of Tertiary volcanism. Economic Geology, 98 (5), 1029-1037, doi:10.2113/gsecongeo.98.5.1029.Feeley, T.C., and Cosca, M.A., 2003, Time vs. composition trends of magmatism at Sunlight volcano, Absaroka Volcanic Province, Wyoming. Geological Society of America Bulletin, 115 (6), 714-728, doi:10.1130/0016-7606(2003)115<C0714:TVCTOM>2.0.CO;2.Giorgis, D., Cosca, M.A., Rumble, D., 2003, Pre-metamorphic d18O signatures in morphologically complex zircons from the Qinglongshan UHP meta-granite (Sulu terrain, China). Swiss Bulletin of Mineralogy and Petrology, 83 (2), 133-144, https://www.ingentaconnect.com/content/ssmp/sbmp/2003/00000083/00000002/art00002.Jourdan, F., Marzoli, A., Bertrand, H., Cosca, M., Fontignie, D., 2003, The Northernmost CAMP: 40Ar/39Ar age, petrology and Sr-Nd-Pb isotope geochemistry of the Kerforne dike, Brittany, France. In: Hames, W.C et al. (eds.) The Central Atlantic Magmatic Province: Fragments of Pangea, AGU Geophysical Monograph, 136, 209-226, doi:10.1029/136GM11.Kirschner, D.L., Cosca, M.A., and Masson, H., 2003, An 40Ar/39Ar, Rb/Sr, and stable isotope study of micas in low-grade fold-and-thrust belt: An example from the Swiss Helvetic Alps. Contributions to Mineralogy and Petrology, 145 (4), 460-480, doi:10.1007/s00410-003-0461-2.Kramar, N., Cosca, M.A., Buffat, P.A., and Baumgartner, L.P., 2003, Stacking fault-enhanced argon diffusion in naturally deformed muscovite. In Vance, D., Muller, W., and Villa, I., eds., Geochronology: Linking the Isotopic Record with Petrology and Textures, Geological Society of London. Special Publication, 220, 249-260, doi:10.1144/GSL.SP.2003.220.01.15.Rodríguez Aller, J., Cosca, M. A., Gil Ibarguchi, J. I., and Dallmeyer, R. D., 2003, Strain partitioning and preservation of 40Ar/39Ar ages for the eclogite-facies stage during Variscan exhumation of a subducted crust (Malpica-Tui allochthon, NW Spain) Lithos, 70 (3-4), 111-139, doi:10.1016/S0024-4937(03)00095-1.Schlup, M., Carter, A., Cosca, M., and Steck, A., 2003, Exhumation history of eastern Ladakh revealed by 40Ar/39Ar and fission-track ages: the Indus River-Tso Morari transect, NW Himalaya. Journal of the Geological Society of London, 160, 385-369, doi:10.1144/0016-764902-084.Feeley, T.C., Cosca, M.A., and Lindsay, C.R., 2002, Petrogenesis and implications of calc-alkaline cryptic hybrid magmas from Washburn volcano, Absaroka Volcanic Province, USA. Journal of Petrology, 43 (4), 663-703, doi:10.1093/petrology/43.4.663.Markley, M., Teyssier, C., and Cosca, M., 2002, The relation between grain size and 40Ar/39Ar date for Alpine white mica from the Siviez-Mischabel Nappe, Switzerland. Journal of Stuctural Geology, 24 (12), 1937-1955, doi:10.1016/S0191-8141(02)00006-8.Mulch, A., Cosca, M.A., and Handy, M.R., 2002, In situ UV-laser 40Ar/39Ar geochronology of a micaceous mylonite: an example of defect-enhanced argon loss. Contributions to Mineralogy and Petrology, 142, 738-752, doi:10.1007/s00410-001-0325-6.Solé, J., Cosca, M., Sharp, Z., and Enrique, P, 2002, 40Ar/39Ar geochronolgy and stable isotope geochemistry of late-Hercynian intrusions from north-eastern Iberia with implications for argon loss in K-feldspar. International Journal of Earth Science, 91, 865-881, doi:10.1007/s00531-001-0251-x.Crowe, W.A., Cosca, M.A., Harris, L.B., 2001, 40Ar/39Ar geochronology and Neoproterozoic tectonics along the northern margin of the Eastern Ghats Belt in north Orissa, India. Precambrian Research, 108 (3-4), 237-266, doi:10.1016/S0301-9268(01)00132-2.D’Atri, A., Dela Pierre, Ruffini, R., Novaretti, A., Cosca, M., Hunziker, J.C., 2001, Calcareous plankton biostratigraphy and 40Ar/39Ar dating of Miocene volcanoclastic layers from Monferrato (NW Italy). Eclogae Geologicae Helvetiae, 94 (2), 137-144.de Sigoyer, J., Chavagnac, V., Blichert-Toft, J., Villa, I., Luais, B., Guillot, S., Cosca, M., and Mascle, G., 2001, Dating the Indian continental subduction and collisional thickening in the northwest Himalaya: Multichronology of the Tso Morari eclogites. Comment and Reply, Geology, 29 (2), 192-193, doi:10.1130/0091-7613(2001)029<0192:R>2.0.CO;2.Edel, J-B., Dubois, D., Marchant, R., Hernandez, J., and Cosca, M., 2001, La rotation miocène inférieur du bloc corso-sarde. Nouvelles contraintes paléomagnetiques sur la fin du mouvement. Bulletin Societé Géologique de France, 172 (3), 275-283, doi:10.2113/172.3.275.Janák, M., Plašienka, D., Frey, M., Cosca, M., Schmidt, S., Lupták, B., and Meres, S., 2001, Cretaceous evolution of a metamorphic core complex, the Verporic unit, Western Carpathians (Slovakia): P-T conditions and in situ 40Ar/39Ar UV laser probe dating of metapelites. Journal of Metamorphic Geology, 19 (2), 197-216, doi:10.1046/j.0263-4929.2000.00304.x.Kramar, N., Cosca, M.A., Hunziker, J.C., 2001, Heterogenous 40Ar* distributions in naturally deformed muscovite: in situ UV-laser ablation evidence for microstructurally controlled intragrain diffusion. Earth and Planetary Science Letters, 192 (3), 377-388, doi:10.1016/S0012-821X(01)00456-3.Odin, G.S., Takahashi, M., and Cosca M.A., 2001, 40Ar/39Ar geochronology of Middle Miocene calcareous nannofossil biohorizhons in central Japan. Chemical Geology, 171 (3-4), 239-252, doi:10.1016/S0009-2541(00)00250-3.de Sigoyer, J., Chavagnac, V., Blichert-Toft, J., Villa, I., Luais, B., Guillot, S., Cosca, M., and Mascle, G., 2000, Dating the Indian continental subduction and collisional thickening in the northwest Himalaya: Multichronology of the Tso Morari eclogites. Geology, 28 (6), 487-490, doi:10.1130/0091-7613(2000)28<487:DTICSA>2.0.CO;2.Giorgis, D., Cosca, M.A., Li, S., 2000, Distribution and significance of extraneous argon in UHP eclogite (Sulu terrane, China): insights from in-situ 40Ar/39Ar UV-laser ablation analysis. Earth and Planetary Science Letters, 181 (4), 605-615, doi:10.1016/S0012-821X(00)00221-1.Zeh, A., Cosca, M., Brätz, H., Okrusch, M., and Tichomirova, M., 2000, Simultaneous horst-basin formation and magmatism during Late Variscan transtension: evidence from40Ar/39Ar and 207Pb/206Pb geochronology of the Ruhla Crystalline Complex, International Journal of Earth Science, 89 (1), 52-71, doi:10.1007/s005310050317.Cosca, M.A., Shimron, A., and Caby, R., 1999, Late Precambrian metamorphism and cooling in the Arabian-Nubian Shield: petrology and 40Ar/39Ar geochronology of metamorphic rocks of the Elat area (southern Israel). Precambrian Research, 98 (1-2), 107-127, doi:10.1016/S0301-9268(99)00044-3.Dèzes, P.J., Vannay, J.-C., Steck, A., Bussy, F., and Cosca, M., 1999, Synorogenic extension: quantitative constraints on the age and throw of the Zanskar Shear Zone (NW Himalaya). Geological Society of America Bulletin, 111 (3), 364-374, doi:10.1130/0016-7606(1999)111<0364:SEQCOT>2.3.CO;2.Guillot, S., Cosca, M.A., Allemand, P., and Le Fort, P., 1999, Contrasting metamorphic and geochronologic evolution along the Himalayan Belt. In: Macfarlane, A., Sorkhabi, R.B., Quade, J. (eds) Himalaya and Tibet: Mountain Roots to Mountain Tops. Geological Society of America Special Paper, 328, 117-128, doi:10.1130/0-8137-2328-0.117.Haeberlin, Y., Moritz, R., Fontboté, L., and Cosca, M., 1999, The Pataz gold province (Peru) within the frame of a mesothermal gold and antimony belt of the Eastern Andean Cordillera. In: Stanley, C.J., et al. (eds.) Mineral deposits: processes to processing. Balkema, 2, 1323-326.Jaboyedoff, M., and Cosca, M.A., 1999, Dating incipient metamorphism using 40Ar/39Ar geochronolgy and XRD modeling: a case study from the Swiss Alps. Contributions to Mineralogy and Petrology, 135, 93-113, doi:10.1007/s004100050500.Mezger, K., and Cosca, M.A., 1999, The thermal history of the Eastern Ghats (India) as revealed by U-Pb and 40Ar/39Ar dating of metamorphic and magmatic minerals: implications for the SWEAT correlation. Precambrian Research 94 (3-4), 251-271, doi:10.1016/S0301-9268(98)00118-1.Cosca, M.A., Arculus, R.J., Pearce, J.A., and Mitchell, J.G., 1998, Inception and early evolution of the Izu-Bonin-Mariana arc system: evidence from 40Ar/39Ar and K-Ar geochronology. The Island Arc, v. 7, p. 579-595.Cosca, M.A., Mezger, K., and Essene, E.J., 1998, The Baltica-Laurentia connection: Sveconorwegian (Grenvillian) metamorphism, cooling, and unroofing in the Bamble Sector, Norway. Journal of Geology, 106 (5), 539-552, doi:10.1086/516040.Markley, M.J., Teyssier, C., Cosca, M.A., Caby, R., Hunziker, J.C. and Sartori, M., 1998, Alpine deformation and 40Ar/39Ar geochronology of synkinematic white mica in the Siviez-Mischabel Nappe, western Pennine Alps, Switzerland. Tectonics, v. 17, p. 407-425.Roberts, D., Cosca, M.A., and Rice, A.H.N., 1998, A 40Ar/39Ar dating study of very low-grade metamorphism from the Rybachi and Sredni Peninsulas, NW Russia-a preliminary report. Norwegian Geological Survey Report, 168, 1-17.Bill, M., Bussy, F., Cosca, M., Masson, H., and Hunziker, J.C., 1997, High-precision U-Pb and 40Ar/39Ar dating of an Alpine ophiolite (Gets nappe, French Alps). Eclogae Geologicae Helvetiae, 90, 43-54.Bryant, C.J., Cosca, M.A., and Arculus, R.J., 1997, 40Ar/39Ar ages of Clarence River Supersuite intrusions from the northern portion of the New England Batholith, southern New England Orogen. In Ashley, P.M. and Flood, P.G., eds., Tectonics and Metallogenesis of the New England Orogen, Geological Society of Australia Special Publication, 19, 242-253.Hoinkes, G., Thöni, M., Lichem, C., Bernhard, F., Kaindl, R., Schweigel, J., Tropper P., and Cosca, M., 1997, Metagranitoids and associated metasediments as indicators for the pre-Alpine magmatic and metamorphic evolution of the western Austroalpine Oetztal Basement (Kaunertal, Tirol). Swiss Bulletin of Mineralogy and Petrology, 77, 299-314.Moecher, D.M., Cosca, M.A., and Hanson, G.N., 1997, Petrologic and 40Ar/39Ar geochronological constraints on the middle to late Paleozoic thermotectonic history of the southern Connecticut Valley zone, New England Appalachians. Geological Society of America Bulletin, 109 (2), 164-175, doi:10.1130/0016-7606(1997)109<0164:PAAAGC>2.3.CO;2.Odin, G.S., Amorosi, A., Tateo, F., Coccioni, R., Cosca, M., Negri, A., Pini, G.A., and Hunziker, J.C., 1997, Chapter C2 Integrated stratigraphy (biostratigraphy and geochronology) of the Early Miocene sequence from the Emilian Apennines (Italy). In Montanari, A., Coccioni, R., and Odin, G. S. (eds.) Miocene Integrated Stratigraphic Sequence, p. 221-248. Elsevier, Amsterdam, doi:10.1016/S0920-5446(06)80020-8.Odin, G.S., Cosca, M., Tateo, F., Negri, A., Vai, G. B., and Hunziker, J.C., 1997, Chapter E2 Integrated stratigraphy of the Late Tortonian Peive di Gesso section (Romagna, Italy). In Montanari, A., Coccioni, R., and Odin, G. S. (eds.) Miocene Integrated Stratigraphic Sequence, p. 449-460. Elsevier, Amsterdam.Odin, G.S., Cuenca Bescós, G., Canuda, J.J., Cosca, M., and Lago, M., 1997, Chapter C5 Biostratigraphy and geochronology of a Miocene continental volcanoclastic layer from the Ebro basin, Spain. In Montanari, A., Coccioni, R., and Odin, G. S. (eds.) Miocene Integrated Stratigraphic Sequence, p. 297-310. Elsevier, Amsterdam.Odin, G.S., d’Atri, A., Tateo, F., Cosca, M., and Hunziker, J.C., 1997, Chapter C1 Integrated stratigraphy near the Oligocene-Miocene boundary in the Piedmont basin (Italy): biostratigraphy and geochronology. In Montanari, A., Coccioni, R., and Odin, G. S. (eds.) Miocene Integrated Stratigraphic Sequence, p. 209-220. Elsevier, Amsterdam, doi:10.1016/S0920-5446(06)80019-1.Odin, G.S., Deino, A., Cosca, M., Laurenzi, M.A., and Montanari, A., 1997, Chapter F1 Miocene geochronology: methods, techniques, and results. In Montanari, A., Coccioni, R., and Odin, G. S. (eds.) Miocene Integrated Stratigraphic Sequence, p. 581-594. Elsevier, Amsterdam.Odin, G.S., Miculan, P., Cosca, M., Tateo, F., Amorosi, A., and Hunziker, J.C., 1997, Chapter D3Biostratigraphy and geochronology of an Early Serravallian volcanoclastic layer from Sicily. In Montanari, A., Coccioni, R., and Odin, G. S. (eds.) Miocene Integrated Stratigraphic Sequence, p. 351-360. Elsevier, Amsterdam.Odin, G.S., Ricci Lucchi, F., Tateo, F., Cosca, M., and Hunziker, J.C., 1997, Chapter E7 Integrated stratigraphy of the Maccarone section, Late Messinian (Marche region, Italy). In Montanari, A., Coccioni, R., and Odin, G. S. (eds.) Miocene Integrated Stratigraphic Sequence, p. 529-544. Elsevier, Amsterdam.Odin, G.S., Takahashi, M., Coccioni, R., and Cosca, M., 1997, Chapter D7 Géochronologie de niveaux situés autour de l’apparition de Globigerina nepenthes au Japon et in Italie: âge de la limite Serravallien/Tortonien. In Montanari, A., Coccioni, R., and Odin, G. S. (eds.) Miocene Integrated Stratigraphic Sequence, p. 393-400. Elsevier, Amsterdam.Odin, G.S., Vai, G.B., Cosca, M., Tateo, F., and Hunziker, J.C., 1997, Chapter E6 Contribution to the geochronology of the Tortonian/Messinian bundary in the Faenza (Romagna, Italy). In Montanari, A., Coccioni, R., and Odin, G. S. (eds.) Miocene Integrated Stratigraphic Sequence, p. 519-528. Elsevier, Amsterdam, doi:10.1016/S0920-5446(06)80038-5.Restrepo-Pace, P.A., Ruiz, J., Gehrels, G., and Cosca, M., 1997, Geochronology and Nd isotopic data of Grenville-age rocks in the Colombian Andes: new constraints for Late Proterozoic-Early Paleozoic paleocontinental reconstructions of the Americas. Earth and Planetary Science Letters, 150 (3-4), 427-441, doi:10.1016/S0012-821X(97)00091-5.Kirschner, D.L., Cosca, M.A., Hunziker, J.C., and Masson, H., 1996, Staircase 40Ar/39Ar spectra of fine-grained white mica: timing and duration of deformation and empirical constraints on argon diffusion. Geology, v. 24, p. 747-750.Schärer, U., Cosca, M., Hunziker, J., and Steck, A., 1996, Termination of major ductile strike-slip shear and differential cooling along the Insubric line (Central Alps): U/Pb, Rb/Sr and 40Ar/39Ar ages of cross-cutting pegmatites. Earth and Planetary Science Letters, v. 142, p. 331-352.Cosca, M.A., Essene, E.J., Mezger, K., and van der Pluijm, B.A., 1995, Constraints on the duration of tectonic processes: protracted extension and deep crustal rotation in the Grenville Orogen. Geology, 23 (4), 361-364, doi:10.1130/0091-7613(1995)023<0361:COTDOT>2.3.CO;2.Crespo-Blanc, A., Masson, H., Sharp, Z., Cosca, M., and Hunziker, J., 1995, A stable and 40Ar/39Ar isotope study of a major thrust in the Helvetic nappes (Swiss Alps): evidence for fluid flow and constraints on nappe kinematics. Geological Society of America Bulletin, 107 (10), 1129-1144, doi:10.1130/0016-7606(1995)107<1129:ASAAAI>2.3.CO;2.Odin, G.S., Coccioni, R., Cosca, M., and Montanari, A., 1995, 40Ar/39Ar geochronology of biostratigraphically controlled Miocene tuffs from central Japan: Comparison with Italy and age of the Serravallian-Tortonian boundary. Chemical Geology, 125 (1-2), 105-121, doi:10.1016/0009-2541(95)00075-W.Ruffini, R., Cosca, M.A., d’Atri, A., Hunziker, J.C., and Polino, R., 1995, The volcanic supply of the Taveyanne turbidites (Savoie, France): a riddle for Tertiary Alpine volcanism. In: Polino, R. And Sacchi, R. (eds.) Rapporti Alpi-Appennino e Guide Alle Escursioni, Accademia Nazionale Delle Scienze Detta Dei XL, Roma, p. 359-376.Schmädicke, E., Mezger, K., Cosca, M.A., and Okrusch, M., 1995, Variscan Sm/Nd and Ar/Ar ages of eclogite-facies rocks from the Erzgebirge, Bohemian Massif. Journal of Metamorphic Geology, 13 (5), 537 - 552, doi:10.1111/j.1525-1314.1995.tb00241.x.Cosca, M.A. and O'Nions R.K., 1994, A re-examination of the influence of composition on argon retentivity in metamorphic calcic amphiboles. Chemical Geology, 112 (1-2), 39-56, doi:10.1016/0009-2541(94)90103-1.Odin, G.S., Assorgia, A., Barca, S., Porcu, A., Spano, J., and Cosca, M., 1994, 40Ar/39Ar geochronology of a Burdigalian tuff from central-northern Sardinia. Giornale Geologia, v. 56, p. 185-197.Odin, G.S., Jelen, B., Drobne, K., Uhan, J., Skaberne, D., PavŠic, J., Cimerman, F.. Cosca, M., and Hunziker, J.C., 1994, Premiers âge géochronologiques de niveaux volcaniclastiques oligocènes de la Région de Zasavje, Slovénie. Giornale Geologia, v. 56, p. 199-212.van der Pluijm, B.A., Mezger, K., Cosca, M.A., and Essene, E.J., 1994, Determining the significance of high-grade shear zones by using temperature-time paths, with examples from the Grenville Orogen. Geology, 22 (8), 743-746, doi:10.1130/0091-7613(1994)022<0743:DTSOHG>2.3.CO;2.Spring, L., Bussy, F., Vannay, J.C., Huon, S., and Cosca, M.A., 1993, Early Permian granitic dykes of alkaline affinity in the Indian High Himalaya of Upper Lahul and SE Zanskar: geochemical characterization and geotectonic implications. Geological Society, London, Special Publications, 74, 251-264, doi:10.1144/GSL.SP.1993.074.01.18.Cosca, M.A., Essene, E.J., Kunk, M.J., and Sutter, J.F., 1992, Differential unroofing within the Central Metasedimentary Belt of the Grenville Orogen: constraints from 40Ar/39Ar thermochronology. Contributions to Mineralogy and Petrology, 110, 211-225, doi:10.1007/BF00310739.Cosca, M.A., Hunziker, J.C., Huon, S., and Masson, H., 1992, Radiometric age constraints on mineral growth, metamorphism, and tectonism of the Gummfluh Klippe, Briançonnais domain of the Préalpes, Switzerland. Contributions to Mineralogy and Petrology, 112, 439-449, doi:10.1007/BF00310776.Cosca, M.A., Essene, E.J., and Bowman, J.R., 1991, Complete chemical analyses of metamorphic hornblendes: implications for normalizations, calculated H2O activities and thermobarometry. Contributions to Mineralogy and Petrology, 108, 472-484, doi:10.1007/BF00303451.Cosca, M.A., Sutter, J.F., and Essene, E.J., 1991, Cooling and inferred uplift/erosion history of the Grenville Orogen, Ontario: constraints from 40Ar/39Ar thermochronology. Tectonics, 10 (5), 959-977, doi:10.1029/91TC00859.Cosca, M.A., Sutter, J.F., and Essene, E.J., 1990, Comment on "Interpretation of K/Ar mineral dates from the Grenville Orogenic Belt." American Journal of Science, 290 (2), 202-204, doi:10.2475/ajs.290.2.202.Cosca, M.A., 1989, Cooling and inferred uplift history of the Grenville Orogen, Ontaria: constraints from 40Ar/39Ar thermochronology: PhD thesis University of Michigan, 235 pp.Cosca, M.A., Essene, E.J., Geissman, J.G., Simmons, W.B., and Coates, D.A., 1989, Pyrometamorphic rocks associated with naturally burned coal beds, Powder River Basin, Wyoming. American Mineralogist, 74 (1-2), 85-100, https://pubs.geoscienceworld.org/ammin/article/74/1-2/85/42195/Pyrometamorphic-rocks-associated-with-naturally.Cosca, M.A., Rouse, R.C., and Essene, E.J., 1988, Dorrite (Ca2(Mg2 Fe3+4)(Al4Si2)O20), a new member of the aenigmatite group from a pyrometamorphic melt-rock. American Mineralogist, 73 (11-12), 1440-1449, https://pubs.geoscienceworld.org/ammin/article/73/11-12/1440/42089/Dorite-Ca-2-Mg-2-Fe-super-3-4-Al-4-Si-2-O-20-a-new.Cosca, M.A., and Peacor, D.R., 1987, Chemistry and structure of esseneite (CaFe3+AlSiO6), a new pyroxene produced by pyrometamorphism: American Mineralogist, 72 (1-2), 148-156, https://pubs.geoscienceworld.org/ammin/article/72/1-2/148/41909/Chemistry-and-structure-of-esseneite-CaFe-super-3.Yau, Y.C., Peacor, D.R., Essene, E.J., Lee, J.H., Kuo, L.C., and Cosca, M.A., 1987, Hydrothermal experiments on candidate packing materials. Clays and Clay Mineralalogy, 35 (4), 241-250, https://pubs.geoscienceworld.org/ccm/article/35/4/241/47021/Hydrothermal-treatment-of-smectite-illite-and.**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.