AGU-CGU Joint Assembly - VGP Session V04

The continental crust is a heterogeneous mixture of materials with varying tectonic and thermal histories. In zones of plate convergence, the response of continental crust to imposed tectonic and gravitational loads is strongly dependent upon its rheology. To better understand the chemical and mechanical evolution of the continental crust in these zones, we must understand the processes that influence crustal rheology. Many recent studies have shown that crustal rheology is strongly influenced by variations in the following parameters: 1) crustal composition and architecture, 2) thermal structure, 3) magmatic history and the presence of partial melt or other fluids, 4) deformation history and strain rates. One area that is yielding particularly interesting results are those studies that address temporal variation in continental rheology and its imprint within the geological record. In many zones of plate convergence, rheological profiles of the deep crust are extremely heterogeneous and can change on time scales that are much less than those that characterize a typical orogenic cycle. For Spring AGU 2004, we propose a special session to Volcanology, Geochemistry and Petrology with co-sponsorship by Tectonophysics that will bring together a variety of studies that can address continental rheology, particularly that of the mid to lower crust, from different viewpoints, including geochemical, petrological, numerical and structural approaches. We are particularly interested in studies that address time-space variations in the rheology of the mid-lower crust and its possible expression in the geological record. We anticipate that the session will attract interest across the spectrum from petrology to tectonics and from geochronology to geophysics, and that it will include contributions from field-based research, experiments and geodynamic modeling.

Conveners: Phaedra Upton, University of Maine, Department of Earth Sciences Bryand Global Sciences Center, Orono, ME 04469 USA, Tel: 207 581 2221, Fax: 207 581 2202, email: [log in to unmask], and Tracy Rushmer, University of Vermont, Department of Geology, Burlington, VT 05405 USA, Tel: 802-656-8136, Fax: 802-656-0045, email: [log in to unmask], and Keith Klepeis, University of Vermont, Department of Geology, Burlington, VT 05405 USA, Tel: 802-656-0247, Fax: 802-656-0045, email: [log in to unmask]