Web: http://fallmeeting.agu.org/2012/
Includes the following sessions:
DI007: Mantle plumes: what do we really know?
Convenors: Dominique Weis (dweis@eos.ubc.ca), Edward Garnero (garnero@asu.edu), Cinzia Farnetani (cinzia@ipgp.fr), Shichun Huang (huang17@fas.harvard.edu)
Mantle plumes provide a likely explanation for the origin of ocean island volcanoes and large igneous provinces, some of which may have caused the largest mass extinctions. Mantle plumes that rise from the core-mantle boundary probe the Earth's deep interior, and thus depend directly on mantle structure, dynamics and evolution. Mantle plumes may also be important for shaping the surface of other planets, such as Mars. In this session, we invite research on terrestrial as well as extraterrestrial mantle plumes, taking a multidisciplinary and integrative perspective from all related fields including, but not restricted to, geochemistry, geodynamics, seismology, geochronology, mineral physics, planetary science, petrology, volcanology and geobiology.
T002: Active Caribbean plate margins: integrating studies for earthquake and tsunami hazard
Convenors: Bernard Mercier de Lepinay (bmercier@geoazur.unice.fr), Eric Calais (ecalais@purdue.edu), Paul Mann (pmann@uh.edu), Pilar Llanes Estrada (pllanes@geo.ucm.es)
Hazards associated with active deformation are often very high along the boundaries of the Caribbean plate. This session targets recent results and upcoming ideas on all active Caribbean tectonic settings from marine and on-land geology, geophysics, seismology, and geodesy, together with modeling studies. Research questions include, but are not limited to, identification of areas with potential for destructive earthquakes, studies of historical and instrumental seismicity, observational and modeling studies of tsunamis, current slip rates on major active faults, studies of strain distribution, accumulation and release, interplate coupling and stress transfer at plate interfaces.
T014: Evolution of the continental lithosphere
Convenors: Anne Meltzer (ameltzer@lehigh.edu), Linda Elkins-Tanton (ltelkins@carnegiescience.edu), Robert Evans (revans@whoi.edu), Matthew Fouch (fouch@dtm.ciw.edu)
Over the past thirty years tremendous progress has been made in understanding the complex processes that shape the continental lithosphere, and much of this progress has been the result of targeted interdisciplinary studies that combine geological, geochemical and geophysical observations with geodynamic modeling. This session highlights these advances, with emphasis on cross-disciplinary studies of continental lithospheric evolution. We welcome contributions discussing continental deformation and lithospheric evolution, the formation and stabilisation of ancient cratons, the formation of continental crust and lithosphere and connections to subduction zone processes, as well as studies of complex areas of continental lithosphere.
T024: Initiation and evolution of rifted continental margins
Convenors: Margaret Benoit (benoit@tcnj.edu), Peter Flemings (pflemings@jsg.utexas.edu), Robert Evans (revans@whoi.edu)
Continental rifts and passive margins record the interplay of surface, crustal, and mantle processes. We seek contributions that emphasize multidisciplinary approaches to illuminate how these systems evolve. We will focus on the following processes: rift evolution; the architecture of rifted margins during and after breakup; and mechanisms and consequences of fluid and volatile exchange between the Earth, oceans, and atmosphere at rifts. We will explore these questions both onshore and offshore. We encourage submissions that emphasize studies of two end-member sites, the Eastern North American Margin and the East African Rift, but submissions on other rifted regions are welcome.
T026: Interdisciplinary perspectives on the origin of intraplate volcanism and large igneous provinces
Convenors: Lapo Boschi (larryboschi@gmail.com), Sebastien Pilet (sebastien.pilet@unil.ch), Maxim Ballmer (ballmer@hawaii.edu)
The expression of intraplate volcanism, as ranging from small seamounts to large igneous provinces, provides clues about mantle dynamics and heterogeneity. However, the controlling mechanisms are controversial and may include lithospheric cracking, small-scale convection, shear-driven flow, fertile mantle heterogeneity, and mantle plumes. Integration of datasets from various disciplines is essential to improve our knowledge of the diversity of intraplate volcanoes observed worldwide. This session will bring together geological, geophysical, petrological and geodynamic studies for a multi-disciplinary discussion on the origin of ocean islands, continental volcanoes, seamounts, and flood basalts.
T029: Magmatism and extension during continental rifting
Convenors: Donald Forsyth (donald_forsyth@brown.edu), Ian Bastow (ian.bastow@bristol.ac.uk), David Ferguson (davef@ldeo.columbia.edu)
Rifting is commonly associated with magmatism, which varies with space, time and geodynamic setting. In East Africa, where the geological record preserves a long history of rift development, the locus of strain has shifted over time from a broad zone of mechanical extension to a narrower zone of magmatism, reminiscent of a mid ocean ridge. In contrast, in the Basin and Range, extension and volcanism have been maintained over a relatively broad area for 15My and the links between magmatism and extension are less clear. We invite contributions from geoscientific studies that constrain the structure and dynamics of all regions of extension with a view to understanding better the manner in which strain and magmatism develop during rifting.
T034: Multidisciplinary studies of failed rift systems
Convenors: Pete Hollings (peter.hollings@lakeheadu.ca), Suzan van der Lee (suzan@earth.northwestern.edu), Irina Artemieva (irina@geo.ku.dk), Carol Stein (cstein@uic.edu)
This session explores current understanding of failed continental and oceanic rifting events in the geologic record. Although continents have successfully rifted apart, with extension eventually resulting in seafloor spreading, in many cases continental lithosphere was intruded, thinned, and extended but did not break apart. There is considerable interest in comparing and contrasting rifts to assess how they started, progressed, and either succeeded or failed.Various seismic experiments around the world, including Earthscope studies in central North America, as well as a mineral boom near North America's failed Midcontinent Rift make this session topical.We welcome presentations on this topic from any discipline.
V005: Calderas I: genesis, evolution, and eruption of large silicic magma chambers – petrology and thermal evolution
Convenors: Heather Wright (hwright@usgs.gov), Kathryn Watts (kwatts@usgs.gov), Catherine Annen (catherine.annen@bristol.ac.uk)
A caldera-forming eruption forms the climax of an eruptive sequence. However, not all volcanoes produce caldera-forming eruptions. What factors contribute to the growth and accumulation of large volumes of silicic magma at caldera volcanoes? What are the time scales by which large silicic magmas are assembled and how do they evolve? We invite contributions that focus on petrologic characterization of eruptive sequences at caldera volcanoes, geochemical signatures of growth and evolutionary processes, and models of magma chamber growth and evolution.
V006: Calderas II: collapse dynamics, unrest and resources – understanding caldera structure and development
Convenors: Valerio Acocella (acocella@uniroma3.it), Joan Marti (joan.marti@ictja.csic.es), Peter Lipman (plipman@usgs.gov), Aldelina Geyer (ageyer@ictja.csic.es)
Collapse calderas are associated with the most catastrophic volcanic events that have occurred on Earth. Nevertheless, many aspects of their development remain unclear. Understanding the structure and development of calderas is crucial for predicting their behaviour during periods of unrest and to plan geothermal and ore exploration. This session will address the principal processes accompanying the development of caldera collapse, including: regional tectonic and magmatic context; conditions for caldera formation, evolution and unrest; potential evolution into an eruption; field evidence for syn-eruptive changes in eruption dynamics and vent geometry; and the role of calderas and their associated structures as sources of geothermal energy and metallic ore deposits.
V014: Erupt, rest, repeat: the nature of cyclic behaviour in volcanic volcanic systems
Convenors: Loyc Vanderkluysen (loyc@asu.edu), Barry Voight (voight@ems.psu.edu), Jean-Francois Smekens (jsmekens@asu.edu), Kirsten Chojnicki (kirsten.chojnicki@asu.edu)
Cyclic eruptive activity is common at many active volcanic centers, spanning a wide range of magma compositions and eruptive styles. In particular, cyclic explosive activity provides optimal conditions to understand the subsurface mechanisms that lead to fragmentation and the transition between effusive and explosive regimes, and observe their surface manifestations. Continuing developments in monitoring techniques provide the scientific community with increasing amounts of data documenting these phenomena. We invite contributions that present results from field observations, laboratory experiments, and numerical or theoretical models of cyclic volcanic phenomena, with a special emphasis on multidisciplinary studies.
V016: Geodynamics and geochemistry of orogenic plateau magmatism
Convenors: An Yin (yin@ess.ucla.edu), Jon Davidson (j.p.davidson@durham.ac.uk), Claudio Faccenna (faccenna@uniroma3.it), Iain Neill (iain.neill@durham.ac.uk)
High orogenic plateaux, including those in Tibet, Iran, and the Andes, are major features of convergent plate boundaries. Causes of plateau formation are widely debated involving both lithospheric and asthenospheric processes. Examination of the voluminous, often mantle-derived, igneous rocks commonly associated with plateaux, may provide clues to the relevance of these and other proposed models in governing plateau growth, support, and demise. In this multi-disciplinary session, we invite contributions from the fields of geochemistry, tectonics, geodynamics and geophysics, which shed insights into the links between magmatic activity and the tectonic origin and evolution of orogenic plateaux, both past and present.
V017: Geodynamics of the Yellowstone hotspot and its track, the Snake River Plain Volcanic Field
Convenors: Robert Smith (robert.b.smith@utah.edu), John Shervais (john.shervais@usu.edu)
This half day interdisciplinary session will evaluate the dynamics and evolution of the Snake River Plain volcanic field and Yellowstone hotspot by addressing: (1) Yellowstone crustal magma reservoir and mantle plume structure from seismic data of the EarthScope TA and electrical structure from MT arrays; (2) data from 3 new deep drill holes of the ""Project Hotspot"" and the International Continental Drilling Program in the Snake River Plain that provide information on the composition, geochemistry, and magmatic processes of the YSRP; (3) earthquake complexities related to tectonic-volcanic interaction; and (4) PBO GPS and strainmeter data on volcano related ground motion and intraplate kinematics.
V019: High resolution geochronology
Convenors: Jan Wijbrans (jan.wijbrans@falw.vu.nl), Leah Morgan (l.e.morgan@vu.nl), Roland Mundil (rmundil@bgc.org), Paul Renne (prenne@bgc.org)
Recent advances in geochronology aim to enhance and widely implement the ability to resolve geologic time with accuracy and precision =< 0.1% level. This goal is proving achievable in some cases and further improvement can be envisioned realistically. We invite contributions that will highlight the state of the art in high-precision, high-accuracy radioisotope geochronology including advances in analytical and computational methods. Both methodological studies and applications to any field in the Earth, life, and planetary sciences are welcomed. Though many efforts thus far have emphasized the U/Pb and 40Ar/39Ar radioisotopic dating techniques, contributions dealing with other systems with potential for improved accuracy and precision are encouraged.
V022: Integrated multidisciplinary constraints on composition and structure of the lithospheric mantle
Convenors: Graham Pearson (gdpearson@ualberta.ca), Derek Schutt (derek.schutt@colostate.edu), Charles Lesher (celesher@ucdavis.edu), Constanza Bonadiman (bdc@unife.it)
The work of Earth scientists from a spectrum of disciplines--geophysicists, geochemists, petrologists, and beyond--gives us complementary information that has great potential for telling us about the nature and evolution of lithospheric mantle. However, it is challenging to formally integrate disciplines due to important differences in how various observables sample the mantle, and to what conditions they are sensitive. In this session, we welcome reports of multidisciplinary approaches to constraining the nature of lithospheric mantle, as well as studies that explore the feasibility and limitations of quantitatively combining various data and methods.
V025: Magmatism and global environmental change – contributions
Convenors: Kirsten Fristad (kirsten.fristad@fys.uio.no), Seth Burgess (sburgess@mit.edu), Linda Elkins-Tanton (ltelkins@carnegiescience.edu), Benjamin Black (bablack@mit.edu)
Increasing evidence suggests that magmatism could serve as a plausible trigger for environmental perturbations ranging from climate change to mass extinction events. New data to further test the plausibility, existence, and mechanics of any such causal connection are therefore crucial. This session addresses the possible links between magmatism and changes in atmospheric and ocean chemistry, climate, and ecology on a range of scales from regional to global. Papers are invited across disciplines including but not limited to volcanology, geochemistry, petrology, geochronology, atmospheric sciences, biogeosciences, ocean sciences, and paleomagnetism.
V026: Mantle plumes: origin, dynamics and evolution
Convenors: Matthew Jackson (jacksonm@bu.edu), Paul Hall (phall@bu.edu), Esteban Gazel (egazel@vt.edu)
From the formation of ocean islands to the eruption of large igneous provinces with their attendant environmental effects, thermochemical anomalies in the mantle known as ""plumes"" have played a fundamental role in the evolution of planet Earth. However, decades after their existence was first posited, a comprehensive understanding of these important dynamical features remains elusive. The goal of this session is to bring together a wide range of disciplines to evaluate the current evidence related to the existence and morphology of mantle plumes, their dynamics and evolution, and the consequences of their interaction with Earth's lithosphere. We encourage contributions from geochemistry, petrology, geodynamics, geophysics and seismology.
V029: Metasomatism: geochemistry, petrology, ore deposits, geophysics
Convenors: Igor Villa (igor@geo.unibe.ch), Daniel Harlov (dharlov@gfz-potsdam.de)
Metasomatism played a major role in the formation and evolution of continental and oceanic crust and lithospheric mantle. Metasomatic processes include ore mineralization and mass transport in, and alteration of, subducted oceanic crust and overlying mantle wedge. Fluid-aided mass transfer and subsequent mineral re-equilibration are the two defining features of metasomatism and metamorphism. Fluid flow is coupled with HP rocks such as granulites and eclogites. Present day movement of fluids in mantle and deep-mid crust can be observed by geophysical data such as seismicity and electrical resistivity.This session aims to bring together a diverse group of geologists, specializing and experienced in all aspects of metasomatism.
V032: Monogenetic volcanism
Convenors: Michael Ort (michael.ort@nau.edu), Ian Smith (ie.smith@aucklund.ac.nz), Paul Wallace (pwallace@uoregon.edu), Shane Cronin (s.j.cronin@massey.ac.nz)
In monogenetic systems the interplay of magma supply rate, source processes and tectonic setting dictates whether primitive or evolved magmas rise to eruption. Source and crustal parameters also control the occurence of dispersed plumbing producing long-lived volcano fields. Petrology, geophysics and volcanology help constrain source and rise models. We seek a broad discussion on the interpretation of geochemical, geophysical and geodynamic and volcanological observations of dispersed volcanism from field to individual volcano scale, and timescales from days to Ma. We particularly want to foster discussion on the role of tectonic setting in producing monogenetic volcanoes and derive an integrated understanding of the drivers and hazards of distributed volcanism.
V035: New developments in petrology addressing Precambrian tectonics and environments for life
Convenors: Eugene Grosch (geogene@gmail.com), Olivier Vidal (olivier.vidal@ujf-grenoble.fr)
The nature of crust formation and tectonics in the Precambrian, have major bearing on the habitats available for life. This session will apply a petrological perspective to answer questions such as: the onset of plate tectonics in the Archean; shear-zone and subduction-related fluid processes; the hydrothermal and surface environments that supported early life. These topics will be addressed by recent advances in petrological techniques, modelling and imaging tools (e.g. SIMS, synchrotron, Raman). The session will focus on novel developments in metamorphic petrology, geochemistry, geochronology, and thermodynamic modelling to better understand conditions in the Precambrian including greenstone belts.