Presents
Location: Stanford University
This will be the 444th meeting since 1954
Mer de Glace, France; long recognized to be efficient agents of bedrock erosion, alpine glaciers have clearly modified local topography. (Shuster photograph)
I will introduce a theoretical basis of low-temperature thermochronology and describe how the open system behavior of parent-daughter isotope systems can be related to topographic evolution of mountain ranges. I will show an example using apatite (U-Th)/He and 4He/3He thermochronometry that constrains topographic evolution in the alpine landscape of Fiordland, New Zealand. The analysis shows that local topography was not in steady state over the last 2 Ma, while erosion removed the entire pre-Pleistocene landscape. The data are best explained by up-valley propagation of erosion through the glacier-carved landscape during this time. This scenario is consistent with a subglacial erosion rate dependent on ice sliding velocity, but not ice discharge. I will also discuss fundamental assumptions and limitations of such applications of thermochronology.
David Shuster (at the base of Mt Tutuko, New Zealand)
Prof. David Shuster (University of California, Berkeley) is primarily interested in processes that occur at and near the surfaces of Earth, Mars and Earth’s moon. His research involves laboratory-based geochemical observations and the development of analytical techniques and numerical modeling tools that utilize noble gases (He, Ne, Ar and Xe) and their relatively simple physical behavior to constrain timescales, rates and temperatures associated with orogenic and planetary processes and chemical weathering. His recent efforts have involved basic research to quantify properties such as kinetics of diffusion and retention characteristics of radiogenic nuclides, and production rates and open system behavior of cosmogenic nuclides. He received his Ph.D. in geochemistry from Caltech in 2005 where he pioneered 4He/3He thermochronometry; he then established and now directs his own research group at Berkeley Geochronology Center, and has been on the U.C. Berkeley faculty since 2010.
Reservations: The preferred way to make reservations is simply to email Mike Diggles at mdiggles@usgs.gov by Feb. 9, tell him you will attend, commit to pay, and bring your payment to the meeting. Mike always emails a confirmation; if you don’t get one, assume email crashed yet again and email him a second time. A check made to “PGS” is preferred, payable at the meeting.
If you want to pay in advance:
Everyone (including Stanford folks now) Please make dinner reservations by Feb. 9. Contact Mike Diggles, at U.S. Geological Survey, 345 Middlefield Road, MS-910 Menlo Park, CA 94025, Tel.: (650) 329-5404. Send check made out to “PGS” to Mike.
Dinner and the social hour is $35.00; this includes $5 that we use to help pay for students who are only $8.00 (also partially subsidized thanks to the School of Earth Sciences, Stanford University (Note, no-show reservations owe the full price).
Doris, whose wonderful crew prepares our meals, asked that we let you know that people who are late RSVPing and people who show up without a reservation will be welcome but that they may be eating on paper plates with plastic utensils (food supply permitting).
Dues for Academic Year 2013-2014 ($10.00) should be sent to Mike Diggles, U.S. Geological Survey, 345 Middlefield Road, MS-910, Menlo Park, CA 94025. Mike’s phone: (650) 329-5404.
Officers: Brad Buerer, President; Mike Diggles, Secretary-Treasurer; Elizabeth Miller, PGS Stanford University Coordinator
Date created: January 19, 2014
Last modified: January 19, 2014
Created by: Mike Diggles, Webmaster-Secretary-Treasurer, PGS.