Apologies for multiple postings.

Dear magma- and arcophiles,

We hope you plan to attend the 2014 GSA Annual Meeting in Vancouver, October 19-22, and that you will consider submitting an abstract to a group of three sessions we are organizing to stimulate discussions on the formation and evolution of continental arcs and individual magma systems at different arc crustal levels and scales.

T15. Continental Arcs #1: Tectonopetrologic Processes Controlling Arc Tempos and Evolution
T16. Continental Arcs #2: Processes at Arc to Magma Reservoir-Scale and Connections from Magma Source to Volcano
T17. Continental Arcs #3: Mapping the Temporal and Compositional Evolution of Subvolcanic Magmatic Systems

Please see detailed information for each session below.

Abstract deadline is July 29. Please submit your abstract via https://gsa.confex.com/gsa/2014AM/cfp.epl

We look forward to your contributions and hope to see you all there!

The organizers of T15, T16 and T17


T15. Continental Arcs #1: Tectonopetrologic Processes Controlling Arc Tempos and Evolution

Conveners: Alan D. Chapman (Missouri S&T), David Pearson (Idaho State), Robert B. Miller (San Jose State), Mark Behn (WHOI)

Sponsors: GSA Structural Geology and Tectonics Division; GSA Geophysics Division; GSA Mineralogy, Geochemistry, Petrology, and Volcanology Division

Invited speakers: Cal Barnes (Texas Tech), Brad Hacker (UCSB) and Jason Saleeby (Caltech)

This session is focused on deep crustal and upper mantle tectonic and petrologic processes; it is one of three sessions that share an overarching goal of better understanding the processes that control the evolution of continental arc systems. The intermediate bulk composition of batholiths is thought to result from interaction between basaltic mantle melts and more felsic supracrustal rocks within the deep crustal roots of arcs. However, the nature of how mantle and crustal components interact within arcs remains poorly understood, due in large part to the rarity of exhumed arc roots in the geologic record. We welcome contributions from a wide range of disciplines (e.g., petrology, geophysics, geochemistry, structural geology, geochronology) focused on the tectonic and petrologic evolution of continental arc systems. A particular focus of this session is to better understand how, and what type(s) of, supracrustal rocks are incorporated into continental arcs and how the inpu
t of these materials may influence magma productivity and composition.


T16. Continental Arcs #2: Processes at Arc to Magma Reservoir-Scale and Connections from Magma Source to Volcano

Conveners: Vali Memeti (Cal State Fullerton), Calvin G. Barnes (Texas Tech), Scott R. Paterson (USC)

Sponsors: GSA Mineralogy, Geochemistry, Petrology, and Volcanology Division; Geochemical Society; GSA Geophysics Division

Invited Speakers: Anita Grunder (Oregon State), Jade Star Lackey (Pomona College), Roberto Weinberg (Monash University)

This session is focused on the chemical and physical processes at different levels and scales of the arc magma plumbing system from source region to volcanoes and their interconnectivity; it is one of three sessions that share an overarching goal of better understanding the processes that control the evolution of continental arc systems. Continental arc magmatic systems are typically characterized by wide compositional variation (gabbroic to granitic) across the vertical extent of the system, from the magma source to the volcanic edifice. The origins of these compositional variations appear to be a complex interplay between source heterogeneity, magma mixing, fractional crystallization, and host rock assimilation, raising important questions about the location, timing, and scale of each process. The source region and intrusions at various levels of the magma plumbing likely represent key locations of such compositional modification, thus better understanding the processes at
 these different levels and their interconnectivity in the overall plumbing system is crucial. In addition, contemporaneous tectonism may have an effect on all aspects of this continental arc factory. We invite contributions from petrology, geochemistry, geochronology, structural geology, tectonics, geophysics, and numerical modeling that address the significance of chemical magma processes at arc to magma reservoir scale and their time and length scales, and the physical processes and mechanisms of magma ‘pooling’ in the source to magma pulsing during ascent and assembly of plutons at different levels of the magma plumbing. We particularly wish to explore chemical and physical evidence for the interconnectivity of the different parts of the magma plumbing, or lack thereof, within the vertical extent of the arc.

T17. Continental Arcs #3: Mapping the Temporal and Compositional Evolution of Subvolcanic Magmatic Systems

Conveners: Erik W. Klemetti (Denison University), Lily Lowery Claiborne (Vanderbilt), Kathryn E. Watts (USGS)

Sponsors: GSA Mineralogy, Geochemistry, Petrology, and Volcanology Division

Invited Speakers: Adam Kent (Oregon State) and Vali Memeti (Cal State Fullerton)

This session is focused on the crystal-scale archives and time-composition-thermal evolution of subvolcanic magmatic systems; it is one of three sessions that share an overarching goal of better understanding the processes that control the evolution of continental arc systems. Subvolcanic magmatic systems in continental arc settings are complex, with a variety of processes such as magma mixing, crystal recycling, rejuvenation and compositional stratification at work, many times simultaneously. In order to better understand the evolution of these complex systems, geochronological and compositional analyses of crystals can be utilized to map these changes. Advances in analytical capabilities have seen a proliferation of these types of studies in recent years. This session will provide an important opportunity for the community to share new insights from crystal-scale archives of magma chamber processes and time-composition-thermal evolution of subvolcanic magmatic systems We p
lan to include time for discussion during the session to bring together varying models, methods, and ideas.


Vali Memeti
Assistant Professor
Dept. of Geological Sciences
California State University, Fullerton
800 N State College Blvd
Fullerton, CA 92831

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http://earth.usc.edu/~memeti/