Location: Stanford University
see Map showing Mitchell
Map showing Bloch
This will be the 352nd meeting since 1954.
D and 
O of authigenic minerals. Development of relief during mountain building often creates lee-side rain shadows in which precipitation is depleted in O and D. The magnitude of this rain shadow effect is strongly correlated to relief in a predictable manner. We compiled O of surface waters along altitudinal traverses in mountain ranges throughout the world (Poage and Chamberlain, 2001). The relationship between net elevation change and 
O allows us to constrain net elevation changes of mountain ranges. We applied this technique to the Southern Alps of New Zealand, the Sierra Nevada of California, the Rocky Mountains and the Himalayan/Tibetan mountain ranges (Chamberlain et al., 1999; Chamberlain and Poage, 2000; Poage and Chamberlain, 2002). Our results show that the Southern Alps were formed in the last 5 Ma, a time when the plate-motion vectors along the Alpine fault changed from dominantly strike-slip to oblique convergence. In contrast, our studies of the Sierra Nevada suggest that this mountain range has been a long-standing tectonic feature for the last 16 Ma, and may have decreased in elevation (Poage and Chamberlain, 2002). And, studies of weathered ashes from the Rocky Mountains indicate similar topographic gradients since the Eocene. The isotopic data from the Himalaya show a marked change in the last 7 Ma. Along the front of the Himalaya in Pakistan O of smectite and calcite increases at 7 Ma, whereas behind Tibet O of calcite decreases in the last 7 Ma. We tentatively suggest that these trends are a result of uplift of Tibet and isolation of the Asian and Indian air masses.
Chamberlain, C.P., Poage, M.A., Craw, D., and Reynolds, R.C., 1999, Topographic development of the Southern Alps recorded by the isotopic composition of authigenic clay minerals. Chemical Geology, 155, 279-294.
Chamberlain, C.P., and Poage, M.A., 2000, reconstructing the paleotopography of mountain belts from the isotopic composition of authigenic minerals. Geology, 28, 115-118.
Poage, M.A., and Chamberlain, C.P., 2001, Empirical relationships between elevation and the stable isotope composition of precipitation and surface waters: considerations for studies of paleoelevation change. American Journal of Science, 301, 1-15.
Poage, M.A., and Chamberlain, C.P., 2002, Stable isotopic evidence for a Pre-Middle Miocene rainshadow in the western Great Basin and Range: implications for the surface uplift of the Sierra Nevada. Tectonics v. 21, 16-1 to 16-10.
If you want to pay in advance:
Stanford faculty and students: Please make dinner reservations by Friday, February 7. Contact Dr. Juhn Liou via his mailbox (and leave check), Geological and Environmental Sciences Office, Geocorner - Bldg. 320 (Rm. 118). Make checks out to"PGS."
All others, including faculty and students from other Bay Area universities and colleges and USGS: Please make dinner reservations by Friday, February 7. Contact Janice Sellers, at Seismological Society of America, 201 Plaza Professional Building, El Cerrito, CA 94530, phone (510) 559-1780. Send check made out to"PGS"to Janice.
Dinner is $30.00. Includes wine (5:30 to 6:15 PM.), dinner (6:15-7:30 PM.), tax, and tip.
For students from all universities and colleges, the dinner, including the social half-hour, is $5.00 and is partially subsidized thanks to the School of Earth Sciences, Stanford University (Note, no-show reservations owe the full price).
Dues for Academic Year 2002-2003 ($10.00) should be sent to Janice Sellers, Seismological Society of America, 201 Plaza Professional Building, El Cerrito, CA 94530. Janice's phone: (510) 559-1780.
Officers: Bob Christiansen, President; Mike Diggles, Vice President; Vicki Langenheim, Secretary; Janice Sellers, Treasurer; Adina Paytan, Field-Trip Czarina
