Month: July 2015

Please see below for sessions of interest to the GeoPRISMS Community, taking place at the 2015 AGU Fall Meeting, December 14-18 in San Francisco. Note, AGU abstract submission deadline is August 5, 2015.

See http://fallmeeting.agu.org/2015/

Submit your abstract: http://fallmeeting.agu.org/2015/abstract-submissions/

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S001: Advances in understanding slow slip and transitional regions

Session ID#: 8822

For investigators working on slow slip or transitional regions of faults, please consider submitting an abstract to our AGU session:

Slow, aseismic slip provides insight into areas of faults where frictional properties transition from unstable stick-slip behavior to stable sliding. Yet our current understanding of the mechanics of slow slip events cannot explain either their broad diversity, both temporal, ranging from days to years, and spatial, or their implications for earthquake hazards. Additionally, slow slip events often exhibit complex interactions with tectonic tremor or earthquake swarms. Slow slip events also load their surrounding environment, including locked seismic faults, and recent evidence suggests that some large earthquakes were preceded by slow slip signals, indicating possible forecasting applications. This session welcomes studies of slow slip observations, including interactions between aseismic slip, tremor, and earthquakes. We also welcome studies of the mechanical properties or physics of slow slip areas, including modeling and laboratory work. In addition, studies relating slow slip processes to seismic hazards are welcomed.

This session is a co-organized session between Seismology, Geodesy, and Tectonophysics.

Conveners:

Noel M Bartlow (University of California San Diego)

Lucile Bruhat (Stanford University)

Heidi Houston (University of Washington)

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V003: A Tangled Web? Generation and transport of fluids, volatiles and melts in subduction zones from source to surface

Session ID#: 9802

We seek to integrate multidisciplinary efforts to advance our understanding of the generation and transport of volatiles and melts in subduction zones to further comprehend the deep volatile cycle and arc magma genesis. New geodynamic models and geophysical imaging techniques continue to improve our understanding of melt and fluid distribution in the mantle. Ground-truth evidence for these models and images is provided through geochemical, petrologic, geochronologic and field studies of lavas erupted on the surface, and the mantle and crust from which magmas are derived and through which they must pass. Thus the tangled web of sub-arc magmatic and volatile cycling is opening to provide a sharper view. This interdisciplinary session invites submissions from geochemistry, petrology, geophysics, modeling, experiments and field geology that address the temporal and spatial evolution of subduction outfluxes, evidence for sub-arc mantle wedge processes and geochemical exchange between Earth’s reservoirs.

Conveners:

Julia Ribeiro (Rice University)

Christy Till (Arizona State University)

Horst Marschall (WHOI)

Leif Karlstrom (University of Oregon)

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V012: Geology, Geophysics, Geochemistry and Biology of Serpentinization Processes on Earth and Other Planets

Session ID#: 8394

This session will focus on the most recent discoveries of the complex hydration reactions of ultramafic rocks in which olivine and pyroxene are reacted to form rocks that are dominated by serpentine, brucite, talc, magnetite and carbonates and are associated with H2 and/or CH4 seeps. Serpentinization involves volume expansion, exothermic heat release, and crustal deformation, coupled with changes in fluid chemistry and seismic properties of the host rock. New insights into how serpentinization reactions proceed and importance of serpentinization as an energy source for microorganisms have been developed from studies on ophiolites and hydrothermal systems.

We invite investigations that concern different aspects of serpentinization such as physical, chemical or biological processes, petrology, fluid-rock processes, mechanics, kinetics of the reactions, volatile transfer (CO2, H2O, O2, SO2), or studies on carbon sequestration and abiotic generation of methane on natural, experimental and numerically modeled systems on Earth and planetary environments.

Conveners:

Aida Farough (Virginia Polytechnic Institute and State University)

Robert P Lowell (Virginia Polytechnic Institute and State University)

Jeffrey Alt (University of Michigan)

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V014: Heterogeneity in the Earth’s interior: the on-going processes of differentiation

Session ID#: 8060

Earth’s interior is compositionally heterogeneous owing to differentiation processes from early in Earth’s history and through the ongoing recycling of lithosphere by modern plate tectonics.  The nature and distribution of these heterogeneities have implications for the convective vigor of Earth’s mantle, its rhealogical structure, processes of magma generation, and the volatile inventory of the whole Earth system.  This session aims for a multi-disciplinary exploration of the nature and fate of mantle heterogeneities in a convective regime, role of heterogeneties in the melting process across tectonic settings, residence times for chemical heterogeneities in the mantle, and the evidence for primordial reservoirs in the deep Earth.  We encourage contributions from all fields including field observations, analytical geochemistry, experimental geophysics and petrology, and numerical modeling.

Our confirmed invited speakers for the session are:

Kate Kiseeva – University of Oxford

Mingming Li – Arizona State University

Sujoy Mukhopadhyay – University of California, Davis

Jackie Li – University of Michigan

We look forward to your submission.

With warm regards,

Fred A Davis (Smithsonian Institution, Washington DC, United States)

Sujoy Ghosh (Indian Institute of Technology Kharagpur, Kharagpur, India)

Ananya Mallik (Bayerisches Geoinstitut, Bayreuth, Germany)

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V016: High-temperature thermochronology: theory, analysis, and application to Earth processes

Session ID#: 7950

Over the past two decades, applications of low-temperature (< 350 ºC) thermochronologic techniques have expanded to include measurement of cooling histories imparted by near surface erosional, burial and tectonic events. Recent studies of more slowly diffusing daughter nuclides within accessory phases have pushed thermochronology to the realm of higher temperatures, with applications focused on measuring cooling rates at deeper crustal levels. Coupled with cooling rates derived from trace element diffusion speedometry, high-temperature thermochronology has the potential to greatly advance understanding of the thermal, and thus geophysical, evolution of the middle and lower crust.

This session will highlight recent advances in assessing thermal histories at greater depths with the Earth’s crust. We encourage abstracts relating to theoretical, analytical, and applied advances in the field of high-temperature thermochronology and geospeedometry.

Conveners:

Terrance Blackburn (UC Santa Cruz)

Andrew Smye (University of Oxford)

Christopher Spencer (Curtin University)

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V038: Transport of Volatiles from Mantle to Surface: Insights on Diffusion, Exsolution and Migration of Fluids in Magmatic Environments from Natural Samples and Experiments

Session ID#: 8051

The transfer of volatiles (H2O, CO2, Cl, S, F) between reservoirs within the mantle, subducted oceanic crust and continental crust 1) influences magmatic processes, 2) modifies trace element and isotope signatures and 3) may change redox conditions. The physical and chemical properties of magmas are significantly influenced by diffusion and exsolution of volatiles during their ascent from the upper mantle through the crust to the surface. For instance, magma degassing may initiate volcanic eruptions, modulates magma viscosity (especially along the conduit) and, thus, affects the eruptive style. This session seeks insights from natural and laboratory observations involving volatile transfer and degassing. Cross-disciplinary studies (e.g. petrology with geophysics and/or geochemistry) providing temporal constraints, and/or involving volatile solubility, fluid and melt composition, isotope signatures and redox conditions are especially welcome.

Confirmed Invited speakers:

Iona M. McIntosh – JAMSTEC, Japan

Kristina J. Walowski – University of Oregon, USA

James D. Webster – American Museum of Natural History, NY, USA

Conveners:

Sarah B. Cichy (Arizona State University, Tempe, AZ, USA; scichy@asu.edu)

Adrian Fiege (University of Michigan, Ann Arbor, MI, USA; afiege@umich.edu)

Thomas Giachetti (Rice University, Houston, TX, USA; tg10@rice.edu)

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V041: Volatile distribution and cycling in the mantle

Session ID#: 7967

Session Description:

The amount, distribution and speciation of volatiles (including H, B, C, N, S and halogens) in the Earth’s mantle are crucial for constraining melting and metasomatism, electrical, thermal and seismic properties, as well as geodynamics. How these volatiles transfer from the crust and the exosphere to the deep Earth and back, or whether some of them originate from primordial reservoirs, is critical to understanding volatile cycling through time and Earth’s planetary origin. We invite contributions that address these issues via natural samples, experiments or models from the scale of minerals to the whole planet. Projects centered on any tectonic setting and mantle depth (from the lower to the upper mantle) and geological time (Archean to present) are welcomed.

Invited speakers:

Rita Parai (Carnegie)

Sylvia-Monique Thomas (University of Nevada, Las Vegas)

Nathalie Bolfan-Casanova (Université Blaise Pascal)

Sincerely,

Anne Peslier

Jaime Barnes

Marion Le Voyer

Jessica Warren

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DI010: Multidisciplinary Views of the Lithosphere-Asthenosphere Boundary and Lithospheric Discontinuities

Session ID#: 8001

There has been a rapid expansion in the number of geophysical studies that detect evidence for abrupt changes in the physical properties at the lithosphere-asthenosphere boundary (LAB) and at additional boundaries within the cratonic and oceanic lithosphere. These mid-lithosphere discontinuities (MLD) and LAB associated boundaries are being discovered in many localities across the globe, though the mechanism(s) underlying the drop in seismic wavespeed, changes in electrical conductivity, and relationship of these observed properties to a rheological transition remain enigmatic. A multidisciplinary approach is fundamental for unraveling the role(s) of partial melt, dissolved water, seismic anisotropy, and/or mineral composition at both the LAB and MLDs. This research is yielding new insights into the growth, stability, alteration, and destruction of plates. Our session welcomes contributions from geophysics (seismology. magnetotellurics, gravity, rheology), geology, geochemistry, mineral physics, and geodynamics that investigate the nature of the LAB/MLD.

Conveners:

Andy Cai (University of Maryland)

Chris Havlin (Lamont-Doherty Earth Observatory)

Anna Kelbert (USGS)

Nicholas Schmerr (University of Maryland)

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EP021: Mass Extraction and Grain Size Fractionation in Sediment Routing Systems: Tracking Sediment from Upland Catchments to the Deep Ocean

Session ID#: 8927

Sediment routing systems carve and construct land- and sea-scapes through erosion, transport and deposition of sediment. Quantifying controls on mass extraction through selective deposition and grain size sorting within sediment transport systems is of paramount importance for predicting geohazards, natural resources, and land/sea-scape evolution. Interactions between fluid, topography and sediment in transport systems subject to steady or changing boundary conditions result in a complex array of local and down-system variability in grain-size. Inverting the resulting stratigraphic record to isolate the key variables can be tremendously challenging. This session will focus on building links between grain size trends, sediment transport dynamics, landscape evolution and basin-scale forcings over diverse spatiotemporal scales. We solicit contributions that use field-based datasets, experimental/ numerical models, and statistical methods to quantify grain-size patterns at a range of scales (from dunes and bars to whole continental margins), and/or temporal changes in grain-size patterns preserved in the stratigraphic record.

Conveners:

Zane R Jobe (Shell Houston)

Anjali M Fernandes (Tulane University of Louisiana)

Nick C Howes (Shell, Houston)

Elizabeth A Hajek (Penn State University)

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T034: New Insights into the Active Deformation and Tectonic Evolution of the Caribbean Plate

Session ID#: 7814

This session seeks to discuss the current state of knowledge of Caribbean plate geodynamics, kinematics and tectonic evolution. Recent studies have quantified how strain is accommodated along the plate boundary, have been able to better constraint geological hazards, and have postulated new models to explain its tectonic evolution. The Caribbean Plate is tectonically active with subduction zones, volcanism, and transpressional zones that produce large seismic and volcanic hazards. The densification of seismic and geodetic instrumentation, capacity building, international collaborations, and collection of new data sets during the past decade are improving our understanding of the Caribbean plate. We seek contributions that use geophysical (seismic, geodetic, remote sensing), numerical and/or analog modeling, and geological techniques to understand strain accommodation along active faults, earthquake, tsunami and volcanic hazards, subduction processes, deformation history, and plate kinematics. This session also encourages contributions on future research directions on tectonics of the Caribbean Plate.

Conveners:

Daniel A. Laó-Dávila (Oklahoma State University)

Alberto M. López (University of Puerto Rico, Mayagüez)

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T045: Tectonic, magmatic, and geodynamic studies of extensional processes: Applications in Iceland and the Nubia-Somalia-Arabia plate system

Session ID#: 8278

We invite contributions focused on understanding tectonic, magmatic, and geodynamic processes during rifting at various stages in development with specific emphasis on case studies in Iceland and the Nubia-Somalia-Arabia plate system. Active extension and volcanism along the East African Rift System as well as the adjoining Red Sea and Gulf of Aden spreading centers provide archetypal environments with which to examine both incipient rifts and recently-established seafloor spreading centers. Iceland offers a unique opportunity to directly observe the subaerial mid-Atlantic ridge – a fully-developed spreading center. We welcome petrological, geochemical, and computational investigations of mantle plume dynamics, extension-related volcanism and volatile flux, and magma supply, generation, and ascent. We also welcome geophysical, geodetic, geodynamic modeling, and geological research to better understand lithosphere-asthenosphere behavior, localization of deformation, mantle structure, structural inheritance, strain partitioning between brittle faulting and sub-surface creep, interplay between faulting and magmatism, and time-dependent plate-boundary deformation.

Confirmed Invited Speakers:

Freysteinn Sigmundsson (University of Iceland)

Wendy Nelson (Towson University)

Cynthia Ebinger (University of Rochester)

Oliver Shorttle (University of Cambridge)

Conveners:

Cory Reed (Missouri University of Science & Technology)

D. Sarah Stamps (Virginia Tech)

Tyrone Rooney (Michigan State University)

Ian Bastow (Imperial College)

We look forward to your submissions, and hope to see you in San Francisco!

Best regards,

Cory, Sarah, Tyrone, and Ian

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MR018: Pore fluids, faulting, and (a)seismicity

Session ID#: 7583

Recent studies highlight the important role pore fluids play in controlling fault slip and seismicity. Fluids are hypothesized to be first-order controls on: slow slip in subduction zones, dynamic weakening of mature plate boundary faults, and triggered seismicity associated with fluid injection. We invite contributions that investigate the mechanical and chemical effects of pore fluids on rock deformation and fault slip. Approaches that merge results of rock deformation experiments and field observations to understand geophysical observations, as well as those that use geophysical observations to infer mechanical processes, are particularly encouraged.

Invited Speakers:

Nick Beeler

Bill Ellsworth

Stephen Miller

Paul Segall

Conveners:

Melodie E French (University of Maryland)

John D Platt (Carnegie Institution for Science)

David L Goldsby (University of Pennsylvania)

Thomas M Mitchell (University College London)

 
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