[margins-list] Tectonophysics Special Sessions at the Spring Joint Assembly

[margins-list at nsf-margins.org]

Dear Tectonophysics affiliates,

The Tectonophysics section has compiled a collection of special sessions 
(listed below) for the Spring Joint Assembly being held this year in 
Toronto from May 24-27th. The sessions cover a broad range of topics 
relevant to the study of the lithosphere and mantle.  We'd like to 
encourage you to submit abstracts to one of these sessions (submission 
deadline: March 4) or to the Tectonophysics General Contributions 
session (T01) and hope to see you in Toronto in May.  First authors CAN
submit more than one abstract for consideration to this meeting.

If you have any questions, please contact the specific session conveners 
or one of the Tectonophysics Program Committee members: Sam Butler 
(sam.butler at usask.ca), Julian Lowman (lowman at utsc.utoronto.ca) or 
Frederik Simons (fritsie at beer.com). More information on the Joint 
Assembly can be found at the following website:

http://www.agu.org/meetings/ja09/index.php

Tectonophysics Special Sessions:

T02: Lithospheric Foundering from Top to Bottom

It has been postulated that the continental subcrustal lithosphere 
(mantle lithosphere) and the lowermost crust in various geological 
regions have been partially or completely removed through delamination 
or convective instability. Seismic studies show, for example, nomalously 
slow zones at lithospheric depths, interpreted to be replacement of 
foundered mantle lithosphere by hot asthenosphere. A range of surface 
geological observables have been attributed to such lithospheric removal 
events. These include: topographic uplift/subsidence, elevated surface 
heat flow, anomalous crustal deformation, and geochemically distinctive 
magmatism/volcanism. However, many fundamental uncertainties remain 
about how and why lithospheric removal happens, what effect it has on 
the crust, whether specific regions identified with removal events are 
correctly interpreted, what characteristics these regions do or do not 
share, etc. We invite contributions that consider these and other issues 
regarding lithospheric removal.

The aim of the session is an interdisciplinary exploration of 
lithospheric removal, and as such we encourage a wide spectrum of 
submissions based on, for example, geophysics, geology, geochemistry, or 
geodesy.

T03: The Seismic Structure and Dynamics of Subduction Zones

Subduction zones are among the most tectonically active and 
heterogeneous places on Earth. Geophysical properties, such as 
seismicity, seismic-wave velocities, anisotropy and attenuation, vary 
significantly among subduction systems. Meanwhile, these observed 
properties are profoundly affected by the dynamics of subduction system 
throughout the tectonic evolution history. For example, hydrous phases 
and water released from slab dehydration reactions possibly contribute 
to intermediate-depth intra-slab seismicity (70-300 km), silent slip 
events, changes in dynamic flow patterns and the abundant volcanism. 
Recently, significant advances in instrumentation and seismic imaging 
techniques have led to high-resolution images and permitted new insights 
into subduction zone dynamics and seismogenesis.

This session is aimed at showing new observations of subduction zone 
structure, and seeking geodynamical and mineralogical explanations. We 
invite contributions from the fields of seismology, geodynamics, 
potential fields, petrological modeling and experiments.

T04: Surface Geological and Tectonic Constraints on Time-dependent 
Mantle Convection

In the last decade the spatial resolution of global seismic tomography 
and mantle convection models has increased significantly. Numerous 
studies have demonstrated that changes in mantle flow patterns can 
influence temporal variations in plate motions, "stability" of 
hot-spots, sea level change, evolution of basins and topography, and the 
strength of the lithosphere.

We invite papers that take multidisciplinary approaches to constraining 
mantle flow with surface observations. In particular, we encourage 
submissions from areas of geomorphology, paleo-oceanography, 
sedimentology, geodesy, geochemistry and seismology to promote 
cross-disciplinary discussions and to advance our understanding of the 
interplay of deep Earth and surface processes that are shaping our Earth.

Regards,
Sam Butler (U. Saskatchewan), Julian Lowman (U. Toronto) and Frederik 
Simons (Princeton U.)