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Department of Geology
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Department of Geology, University of Maryland
Fall 2009 Geochemistry Seminar SeriesWednesdays 11:00am - 12:00pm September 16 Jay Kaufman, University of Maryland "A glacial divide between Ediacaran extinction and the Cambrian explosion of life" September 23 Francis McCubbin, Geophysical Lab, Carnegie Institution of Washington "Magmatic volatiles on the Moon and Mars: Inferences from sample analysis" September 30 Bill Walters, Chemistry Department, University of Maryland "Creation of the chemical elements that underlie Solar System Abundances" October 7 Brian Harms, University of Maryland "Ancient speleothems: high-resolution archives of Earth's past climate" October 14 Madalyn Blondes, University of Maryland "Thermal history of the deepest parts of orogens through U-Pb thermochronology of Tanzanian deep crustal xenoliths"
October 21 Harry Oduro , University of Maryland "Insight from Sulfur Isotope Fractionation to Assess the Formation and Degradation of Environmental VOSCs and Related Sulfonium Compounds" October 29 Graham Begg, International traveling speaker for the Society of Economic Geologists "The Lithosphere, Geodynamics and Metallogeny" November 4 Sarah Penniston-Dorland, University of Maryland "High P/T blocks with actinolite schist rinds: Evidence for element mobility from the Franciscan Complex, CA" November 11 Jingao Liu "Geochemical processes acting on mantle peridotites: evidence from distinct HSE patterns" November 18 Lin Qiu "TBA" December 2 Xiaoming Liu "Fire and Water: A Fieldtrip to the Central and Eastern Portions of the Columbia River Flood-Basalt Province" ***SPECIAL SEMINAR*** Wednesday December 9 John Suppe, Department of Geosciences, National Taiwan University "Deep and shallow structure of the Taiwan arc-continent collision" Abstract: The on-going oblique arc-continent collision in Taiwan between the Luzon arc and the Eurasian continental margin provides a classic spatial view of the temporal evolution of the collision. In addition Taiwan is a well-known site of critical-taper wedge mechanics and erosional forcing of deformation, leading to a mountain belt that is approximately in topographic steady state, with erosion balancing the compressive flux. This classic picture, based largely on surface and upper-crustal data, is now being illuminated at lower crustal and upper mantle levels with highresolution local seismic tomography and earthquake locations. These new data document in 3D that the deep structure is remarkably independent of the shallow thinned-skinned mountain belt. Here we show that the lower crust and upper mantle of the Eurasian plate undergoes a transition from normal subduction and accretionarywedge tectonics south of Taiwan to a strongly localized progressively bent geometry with a vertical to overturned plate interface. The lower crust and Moho of the Eurasian plate is vertical to overturned to depths of 70-80 km under central and northern Taiwan. In this region the deep plate shortening is accomplished by folding of both the Eurasian and Philippine-Sea lower lithospheres without an active subduction zone, whereas the crust of both plates above the main detachment is mechanically and kinematically separated from this deep shortening The coordinator for the Geochemistry Seminar Series is Dr. Madalyn Blondes. You can contact her at mblondes AT umd.edu |