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Spring 2019 Colloquia

January 7: No Colloquium

January 14: Colloquium: EAS faculty candidate

January 21: No Colloquium - Martin Luther King Day

Tuesday, January 22: Colloquium: EAS faculty candidate

January 28: Colloquium: EAS faculty candidate

February 4: Colloquium: EAS faculty candidate

February 11: Jose Luis Antinao, IGWS. Title: A Quest across Hemispheres: Understanding the Linkage between Vegetation Change and Alluvial Fan Aggradation in Arid Regions

Abstract: A widely used model for occurrence of alluvial fan aggradation in arid regions states that at timescales of tens of thousands of years timescales, changes between climate states causes hillslope vegetation change, driving a disequilibrium in the hillslope sediment transport system that ultimately generates aggradation in alluvial fans downstream. The discrete sedimentation pulses observed in Late Quaternary alluvial fans of arid southwestern North America have been explained by invoking this mechanism. Extensive research during the past decades has tried to test this hypothesis not only in the arid southwestern continent, but also in other arid regions.

In this talk, I will focus on how our understanding on alluvial fan sedimentology, timing, and the relation with paleoenvironmental change has improved over the last decade in areas across North and South America, and how this has enabled us to develop new hypotheses that complement the original ideas in the model. I will highlight the critical role that coupled geochronology tools like optically stimulated luminescence and cosmogenic exposure dating have played along with quantitative techniques for soil chronosequence analysis, drawing examples from research in Mexico, the Mojave and the arid Andes.

February 18: Bob Wintsch, EAS Professor Emeritus Title: Chemical Role of Fluids and Mechanical Role of Minerals in Fault Zones

February 25: No Colloquium

March 4: Sarah Brownlee, Wayne State University Detroit. Title: Seismic anisotropy in the middle and lower continental crust: Using rocks to improve seismic interpretations

March 11: Spring Break - no colloquium.

March 18: Keith A. Hobson, University of Western Ontario, Environment Canada Science and Technology Title: Using stable isotopes to track migratory animals

Abstract: The conservation of migratory wildlife requires that we link breeding, stopover and wintering sites of regional populations and identify which factors may be operating to limit populations. This is easily said but difficult to achieve, especially for small songbirds and insects that are rarely encountered and which are typically unable to be equipped with satellite transmitters. For the last decades, I have been working on the use of intrinsic chemical fingerprints (stable isotopes of key elements such as C,N,O,H,S) primarily in bird feathers and insect wings to provide geographic information of origins. The advantage to such an approach is that only one capture is required and sampling is not biased to the relatively few locations where organisms can be marked. This approach has provided a breakthrough in the way we can forensically track wildlife by making use of naturally occurring biogeochemical “isoscapes”. I will provide an overview of this technique and provide many examples from birds to butterflies. I will also try to address where the isotope approach now sits given the advent of new and exciting technologies such as miniaturized light-level geolocators and Motus tags.

March 25: Adam Forte, Louisiana State University. Title: Decoupling of modern tectonics, climate, and topography in the Greater Caucasus.

Monday, April 1: Tudor Lecture: Kyle Anderson, Research Geophysicist, USGS Title: TBA

April 8: Derek Sawyer, Ohio State University Title: TBA

April 15: Nicholas Famoso, Chief of Paleontology John Day Fossil Beds National Monument, University of Oregon Department of Earth Sciences Title: TBA

Tuesday, April 23: Brooks Proctor, Research Geologist USGS Menlo Park. Title: TBA