Rocky Mountain GSA theme session and field trip
From: Allen Stork <astork@xxxxxxxxxxx>
****************************************************************************************
Dear colleagues,
Please, consider submitting an abstract for the upcoming Rocky Mountain GSA meeting (15-17 May 2013, Gunnison, CO). The deadline for submission is TOMORROW (February 12th), 11:59pm Pacific Time.
We welcome contributions to the following session:
Cenozoic Magmatism of the San Juan Mountains: Plutons to Volcanoes
The San Juan Mountains preserve one of greatest records of combined magmatism, volcanism, and mineralization in all of geologic history. They have been an important site to test ideas about continental volcanism and landscape evolution for over 100 years. In this session we invite contributions on all aspects of magmatism in the San Juan Mountains and the adjacent areas of the Southern Rocky Mountain volcanic field. We encourage submissions on any aspect of the volcanic field including the pre-caldera, caldera-forming and post-caldera magmatism and related geologic phenomena.
If you can come a little early sign up for a field trip.
From Ignimbrite to Batholith, NE San Juan Mountains.
Tues., 14 May. US$90.
Peter Lipman, USGS, plipman usgs.gov.
The northeastern San Juan Mountains, the least-studied portion of this well-known volcanic region, are the site of several newly identified and/or reinterpreted ignimbrite caldera systems that overlie a large geophysically imaged granitic batholith. We will (1) view features of the Cochetopa Park caldera, presenting evidence that no large explosive eruptions vented from this morphologically beautifully preserved caldera—rather, Cochetopa Park subsided passively as the >500 km3 Nelson Mountain Tuff vented at 26.9 Ma from an "underfit" caldera 30 km to the SW; (2) traverse the recently recognized North Pass caldera, source of the 32 Ma Saguache Creek Tuff, a regionally distinctive crystal-poor alkalic rhyolite that bridges an apparent gap in the southwestward migration from older explosive volcanism in central Colorado to the culminating locus of Tertiary volcanism in the central San Juan region; and (3) focus on the 33.2 Ma Bonanza caldera, characterized by an array of exceptional features, including exposed levels from near-original rim down through caldera floor, 3.5-km thick caldera-filling ignimbrite and lavas, exceptionally steep resurgent dome, and associated granitic intrusions. New Ar-Ar single-crystal age determinations are critical to these reinterpretations.
http://www.geosociety.org/Sections/rm/2013mtg
Dave Gonzales, Fort Lewis College, gonzales_d@xxxxxxxxxxxxx;
Allen Stork, Western State Colorado University, astork@xxxxxxxxxxx.
Allen Stork
Professor of Geology
Western State Colorado University
Gunnison, CO 81231
==============================================================
Volcano Listserv is a collaborative venture among Arizona State University (ASU), Portland State University (PSU), the Global Volcanism Program (GVP) of the Smithsonian Institution's National Museum of Natural History, and the International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI).
ASU - http://www.asu.edu/ PSU - http://pdx.edu/ GVP - http://www.volcano.si.edu/ IAVCEI - http://www.iavcei.org/
To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx.
To contribute to the volcano list, send your message to: volcano@xxxxxxx. Please do not send attachments.
==============================================================
