Web: http://fallmeeting.agu.org/2015/
Includes the following sessions:
T050: The Parana-Etendeka Igneous Province and Related Magmatism: What Have we Learned so far?
Convenors: Edgardo Canon-Tapia (ecanon@cicese.mx), Irene Raposo (irene@usp.br), Xixi Zhao (xzhao@tongji.edu.cn)
The Paraná-Etendeka Igneous Province (PEIP) of Brazil and Namibia is the second largest outcrop of the Cretaceous continental flood basalt; it is closely related to the opening of the South Atlantic Ocean, and was followed by many intrusions, some of which might lie outside the present day Paraná Basin. Numerous studies describing the geochemical, geochronological, geophysical, paleomagnetic, stratigraphical, tectonic and volcanic characteristics of the PEIP proper, and the associated magmatism on both sides of the Atlantic, have been published in the past decade. However, it is difficult to assess how much has been learned about this province, partly because those works are outpaced in the literature. This session therefore invites recent studies in all subjects that contribute for a better knowledge of the origin and evolution of the PEIP and related magmatism. We also encourage multidisciplinary studies allowing comparison of the PEIP with other continental flood basalt provinces.
V037: The Tempo of Continental Flood Basalt Eruptions
Convenors: Loyc Vanderkluysen (loyc@drexel.edu), Stephen Self (steve@stephenself.com), Paul Renne (prenne@bgc.org), Andrea Marzoli (andrea.marzoli@unipd.it)
Continental Flood Basalt (CFB) eruptions play an important role in mass and energy fluxes between the mantle, crust, and atmosphere, and at least the last four mass extinctions are associated closely in time with CFB "main-phase" eruptions. However, a better understanding of the timing and rate of CFB eruptions relative to paleontological and geochemical markers of major biospheric disturbances is necessary to further progress in understanding possible causal relations, as well as achieving a more fundamental geodynamical and petrological understanding of the genesis of these extraordinary volcanic events. This session provides a forum for presentation of new results or reviews from diverse fields including geochronology, volcanology, petrology, geochemistry, paleontology, and geophysical and atmospheric modeling that bear on this theme.
P031: The Physical Conditions controlling Life's Origin, Evolution, and End
Convenors: Daniel Knoll (dkoll@uchicago.edu), Jun Yang (junyang28@uchicago.edu), Nathaniel Baskin (nbaskin@uchicago.edu)
New insights into Mars’ wet past, the confirmation of a liquid ocean on Ganymede, and the ongoing stream of exoplanet discoveries raise the prospect of an ever-wider range of environments that could sustain life. This session explores how such environments emerge, are sustained, and eventually decline. Questions of particular interest include: What is Earth’s long-term climatic stability and how will it end? How long did habitable conditions persist on Mars and did they ever exist on Venus? What habitable environments exist in the outer Solar System and how do they continue to evolve? How do the Faint Young Sun Problem, the Runaway Greenhouse, and long-term climate feedbacks play out across different planets and outside the Solar System? We invite case studies and comparisons that use observations, experiments and/or modeling to expand our understanding of the habitability of diverse environments in our Solar System and beyond.
DI001: Across the Scales: Earth's Mantle Dynamics Through Space and Time
Convenors: Keely O'Farrell (k.ofarrell@ucl.ac.uk), Tobias Rolf (tobias.rolf@geo.uio.no), Shijie Zhong (shijie.zhong@colorado.edu), Anne Davaille (davaille@fast.u-psud.fr)
From small-scale convection underneath tectonic plates to huge thermochemical features such as the LLSVPs in the lower mantle, mantle dynamics is a multi-scale process! It includes everything from the cooling of the early magma ocean, to the formation of plumes, the assembly of supercontinents and the long-term secular cooling. Revealing how processes on these different temporal and spatial scales operate, interact, and produce surface observations in volcanism, tectonics, gravity anomalies and sea-level changes is thus of great importance for understanding Earth’s evolution and dynamics. This session aims to shed light on these processes, including (but not limited to) formation and dynamics of mantle structures, dynamics of plate tectonics and continental drift, and magma ocean dynamics. We welcome theoretical, numerical, laboratory and observational studies from a wide range of disciplines that contribute to understanding these multi-scale processes.
PP015: Evolution of the Earth System
Convenors: Colin Goldblatt (czg@uvic.ca), Benjamin Johnson (ben.w.johnson3@gmail.com)
Earth has evolved as a coupled system, with rich interactions between biology, geology, chemistry and climate. A wide array of geochemical and climatic states have existed through a continuously habitable period of at least 4 billion years. Understanding this evolution is necessarily an interdisciplinary problem. We welcome contributions which chart or explain this evolution, with either observational or theoretical approaches, for any period in Earth history. Topics will include evolution of major geochemical cycles (C, O, N), major climatic events and the co-evolution of life and the environment.
V046: Yellowstone volcanism from its current expression to early vestiges of hotspot activity via geophysical and petrologic studies
Convenors: Matthew Loewen (loewenm@uoregon.edu), Ilya Bindeman (bindeman@uoregon.edu), Eugene Humphreys (gene@newberry.uoregon.edu)
The Yellowstone-Snake River Plain magmatic province represents one of the largest worldwide centers of bimodal rhyolitic-basaltic volcanism. Although not universally accepted, recent geophysical imaging and geochemical tracers provide strong evidence that the volcanism is driven at depth by a mantle plume from ~17 Ma volcanism in SE Oregon- SW Idaho to present volcanic activity in Yellowstone National Park. Recently studies have also recognized potential earlier traces of the Yellowstone plume in 17+ Ma volcanic centers across Oregon to a 55+ Ma Pacific origin. Advances in geochemical microanalysis, geochronology, numerical modeling, and geophysical imaging are providing new clues to understanding the mantle origin of the hotspot, crustal structures and magma reservoirs, and mechanisms for rhyolite generation and eruption triggering. We seek interdisciplinary contributions from petrologic and geophysical studies or modeling that are working to progress our understanding of current or past state of the Yellowstone hotspot and its volcanoes.
T038: Rifts and Passive Margins: Tectonics, Dynamics, Processes
Convenors: Sascha Brune (sascha.brune@sydney.edu.au), Peter Clift (pclift@lsu.edu), Gwenn Peron-Pinvidic (gwenn@ngu.no), Giacomo Corti (giacomo.corti@igg.cnr.it)
This session presents recent advances on rifts and passive margins from geological and geophysical studies that are based on seismic interpretation, field geological data, plate reconstructions, sedimentology, and modeling. We aim to assemble presentations on basin, regional and global scale that provide new insight on rift evolution in terms of inheritance and strain localization, fault interaction and stratigraphy, partial melting and volcanism, surface stress evolution, tectonics-climate interaction, small-scale convection, driving forces, and rift-to-drift transition. Most rifts feature significant along-strike structural variations. We therefore particularly encourage abstract submission on 2D investigations with regional perspective, 3D seismic arrays, as well as 3D analogue and numerical experiments. Special emphasis will be put on contributions that develop an integrated picture by bridging multiple spatial or temporal scales or by combining results from active rifts, failed rift arms, passive margins or obducted rifted margins.
DI009: Mantle Plumes From Head to Toe
Convenors: Eric Mittelstaedt (emittelstaedt@uidaho.edu), Dominique Weis (dweis@eos.ubc.ca), Peter Van Keken (keken@umich.edu)
Rising mantle plumes carry mass, heat, and chemical anomalies from their ‘toes’ at the base of the mantle to their ‘heads’ near the surface, where plumes spread beneath the lithosphere. Recent investigations reveal growing evidence for complex plume dynamics near the Core-Mantle Boundary (CMB) and interactions with tectonic plates. Near the CMB, slow shear velocities suggest the existence of large piles of chemically anomalous material that change plume structure and control plume initiation. This material may be incorporated into plume stems, altering the composition of hotspot lavas. Near the surface, spreading plume heads are the source of chemically anomalous hotspot lavas, dynamic topography, and changes to lithospheric deformation and rifting. This session aims to take a broad view of mantle plumes, looking at advances in understanding of their formation, rise, lithosphere interaction, and eventual effect on surface processes. We welcome recent work on plumes at all scales and depths.
T022: Geologic and geodynamic evolution of the Arctic region
Convenor: Eric Gottlieb (esgeo@standford.edu), Richard Lease (rlease@usgs.gov), Richard Saltus (saltus@usgs.gov), Tim O'Brien (timothy3@stanford.edu)
Over the last quarter century, scientific and entrepreneurial agendas for the Arctic have expanded greatly as climate change, international politics and technological innovations have diminished logistical barriers and opened a modern frontier for scientific and resource exploration. Despite years of study, much of the framework geologic history of the Arctic Ocean and its surrounding landmasses is insufficiently constrained by existing data and is thus controversial. Elucidating the multiphase plate tectonic history of the oceanic and surrounding continental realms through robust plate reconstructions and regional tectonic syntheses is a fundamental challenge. We seek research that addresses the challenging geology of the Arctic, especially submissions that integrate understanding of (1) age, lithology, structure, and/or paleo-(bio)geography of circum-Arctic lithosphere, (2) tectonic and geodynamic processes of lithosphere generation and modification, and (3) geologic and geophysical correlations across the oceanic realm and into better-studied regions of Eurasia, Laurentia and elsewhere.
V020: Interdisciplinary perspectives on continental crust evolution
Convenors: Bruno Dhuime (b.dhuime@bristol.ac.uk), Esteban Gazel (egazel@vt.edu), Claire Bucholz (cbucholz@mit.edu), Jeroen Van Hunen (jeroen.van-hunen@durham.ac.uk)
There are still many outstanding questions regarding the modus operandi of continental crust formation and destruction, its volume, composition, thickness, and its interaction with the mantle and the atmosphere through time; especially during the early stages of Earth's evolution. New perspectives are rising from the increased understanding of the geochemical record preserved in igneous and sedimentary rocks, minerals and their inclusions, the improvement of analytical techniques, and the development of both analogue and numerical modeling of crust-mantle interaction through time. This session welcomes contributions that address the origin and evolution of the crust and/or the lithosphere, using one or a combination of these different approaches. Contributions that present new approaches and/or new (interdisciplinary) analytical techniques will be particularly welcome.
T020: Formation and evolution of the North American continental lithosphere
Convenors: Amy Gilligan (a.gilligan@imperial.ac.uk), Fiona Darbyshire (darbyshire.fiona_ann@uqam.ca), Ian Bastow (i.bastow@imperial.ac.uk)
The North American continent records more than 3 billion years of the Earth’s tectonic history in its present day lithospheric structure. Geophysical data coverage of North America has vastly improved in recent years, thanks to ongoing large-scale projects such as EarthScope and POLARIS. This wealth of new geophysical data is permitting detailed studies of Earth structure in previously under-represented parts of the continent. New results emerging from studies using these data suggest that the “stable” continental core in the central and eastern regions is as structurally and dynamically complex as the tectonically-active west. We welcome submissions related to structural, tectonic and geodynamic studies of the formation and evolution of North America, with particular emphasis on geophysical investigations of the upper mantle.