Fall 2009 Colloquia

September 7: Whitey Hagadorn, Amherst College Surfing Cambrian shorelines. 4:00 p.m. GY126

September 14: Rich Adams, Carr Resources Inc.Basement Tectonics and Origin of the Sabine Uplift, Gulf of Mexico Basin

September 21: NO COLLOQUIUM Eastern Section AAPG in Evansville, Indiana

September 28: Phil Stevens, SPEA Indiana University Oh where, oh where is OH? Measuring the elusive hydroxyl radical in the atmosphere

October 5: John Rupp, Indiana Geological Survey The Role of Geological Sequestration in the Midwest –Assessing the Successes and Challenges

October 12: Mary Parke, Indiana Geological Survey Characterizing oil and gas reservoirs in Indiana

October 19: GSA Annual Meeting Portland Oregon

October 26: Mike Snow, Physics Department, Indiana University What scientists learn when they slow down and scatter neutrons

November 2: Mike Prentice, Indiana Geological Survey The Response of Ice Sheets to Climate Change: A Geological Perspective about the West Antarctic Ice Sheet

November 9: Craig Lundstrom, University of Illinois Magma differentiation by top down reaction-crystallization: implications for zoned pluton formation, continental crust production and volcanic hazards assessment

November 16: Arvid Johnson, Purdue University How to read ground fractures as one walks along the ground surface

November 23: Thanksgiving Break

November 30: Tim Filley, Purdue University. Title: Soil Organic Matter Dynamics and Feedbacks Within the Soil-Earthworm-Litter System (or Global Worming)

Abstract : To accurately predict how soil organic matter will respond to future global and regional environmental change soil scientists must have a detailed accounting of the biogeochemical factors that control the dynamics of soil organic matter stabilization/destabilization. Important insights into this area have been made through the combined approaches of soil physical fractionation, based upon a mineral association and aggregate hierarchy perspective of soil stability, and the structural and isotopic characterization of their constituent microbial and plant-derived biopolymeric components. Recent work exploiting the natural isotope shifts in plant communities or applying enrichment labeling techniques has demonstrated how organic matter derived from plant biopolymers such as lignin, cutin, and suberin are decomposed, partitioned, stabilized or destabilized in nature. Important questions concerning the response of forest and grassland soils to a number of environmental stresses can benefit from the above approach. For example, in forests where exotic earthworm (EW) species have been introduced they have been shown to alter the chemical trajectory of litter decay, change the chemistry of soil organic matter, shift microbial populations and activity, and alter soil horizon profiles. Such considerations are particularly relevant for ecosystems free of EWs, such as in many northern North American forests where native EW populations did not repopulate after the last major glaciations. In this talk I will present research on SOM dynamics driven by changes to above and below ground productivity from two North American free air CO2 enrichment (FACE) experiments. The role that native and invasive earthworms play in the selective packaging and delivery of plant tissue to these soils and how their presence influences how these CO2 fumigation experiments alter soil organic matter accumulation will be highlighted.

December 7: Ramon Arrowsmith, Earthscope Speaker, Arizona State University High spatial resolution tectonic geomorphology of active fault zones of western North America.