Abstract submission and directions are available at http://goldschmidt.info/2014/abstractsInfo
Session 5: Mantle to Crust
• 05b: Magma Generation/Evolution and Oceanic Crust Formation at Mid-Ocean Ridges and Interoceanic Arcs
Magmatism in the ocean basins is responsible for forming the igneous crust of two-thirds of Earth’s surface and for a significant portion of mass and heat transfer from the mantle into the oceanic crust and oceans. Petrologic, geochemical, geochronological and geophysical studies of oceanic magmas at a range of spatial and temporal scales (from single eruptions to volcano-scale sampling) in both extrusive and intrusive sections (e.g., by drilling and in ophiolites) have revealed the operation of a wide range of magmatic processes. This session will investigate the latest results to inform our understanding of how the full range of these processes and conditions act to control oceanic magmatism at spreading centers and arcs (including mantle melting style and depth, mantle fluids and metasomatism, melt-rock reactions in the mantle and crust, and eruption of magmas or entrapment as plutons). The session welcomes contributions from petrological, geochemical, geochronological, geophysical, experimental and modeling studies of igneous processes and oceanic crust formation in modern and ancient oceanic settings.
Keynote speaker: Sensumu Umino
Invited Speakers: Dorsey Wanless (and others pending their acceptance).
Convenors: Ken Rubin, Laurence Coogan, Yaoling Niu
• 05f: Serpentinization Processes: From Mantle to Microbe, Past and Present (Conveners: Muriel Andreani, Susan Lang, Thomas McCollom)
Session 6: Continental Crust
• 06c: Putting the Little “t” in P-T-H2O-T: Novel Integrations of Geochronology and Thermodynamics in Diverse Tectonic Regimes (Conveners: Ethan Baxter, Michael Williams, Stacia Gordon, Clare Warren, Emilie Janots)
• 06e: The Dynamic Margins of Continents (Conveners: Oliver Jagoutz, Mark Behn, Mihai Ducea, Peter Clift)
Session 7: Subduction
• 07a: Geochemical, Petrological, and Physical Controls on Arc Eruptions (Conveners: Caroline Bouvet de Maissoneuve, Philipp Ruprecht, Tom Shea)
• 07b: New Advances in Subduction Zone Magma Genesis
Magmatism at the Earth’s dynamic subduction zones generates volatile-rich, andesitic magmas that resemble continental crust in composition and form an integral part of the broader geochemical cycles on Earth. The plate tectonic concept brought the recognition that andesite genesis is causally linked to slab subduction and major strides have been made in the past decades towards understanding subduction cycling. However, it remains unclear the extent recycled slab materials (subducted trench sediment, igneous oceanic crust, serpentinitized mantle, and eroded crust) affect the major and trace element chemistry of primary arc melts. How much slab material is contained in primary arc magmas? Are primary arc magmas basaltic or silicic or both? How are slab materials principally transferred to the mantle (fluids? silicic melts? mélange diapirs?). Do these components react and hybridize with the subarc mantle, or rather pass through it? What is the role of the overlying crust in modifying melt compositions? What are the timescales of slab material transfer through mantle and crust? This session seeks new concepts of material processing at convergent margin that challenge the classical model of basaltic arc magma formation from subarc mantle with only minor mass contributions from the subducted slab. Case studies and conceptual approaches from all disciplines are welcome, including field studies, experimental petrology and geophysical approaches ranging from fluid dynamics to seismology. Contributions that address the quantification of mass transfer from slab to arc are particularly encouraged.
Keynote speaker: Arturo Gomez-Tuena (on slab diapirism and more)
Invited Speaker: Fang Huang
Convenors: Susanne M. Straub, Heather Handley, Marc-Antoine Longpre
• 07d: From Batholiths to Continents: Supply, Storage, and Processing of Arc Magmas in the Crust (Conveners: Jade Star Lackey, Cin-Ty Lee, Steven Shirey, Blair Schoene)
• 07f: Geologic and Geochemical Processes at the Plate Interface (Conveners: Sarah Penniston-Dorland, Christy Till, Taras Gerya)
Session 8: Melts, glasses, magmas
• 08d: Small Scale Heterogeneities in Magmatic Systems: Melt Inclusions, Glasses and Minerals (Conveners: Estelle Rose-Koga, Marion Le Voyer, Kenji Shimizu, Fidel Costa)
Session 12: Geochemistry of Volcanic Systems and Natural Hazards
• 12d: Geochemistry and Mineralogy of Earthquakes and Faults (Conveners: Diane Moore, Tetsuro Hirono, Perach Nuriel)
• 12f: Tracking Volatiles: Magmatic Volatiles, Degassing, Eruptions, Volcanic Lakes, and the Environment (Conveners: Youxue Zhang, Joop Varekamp, Dmitri Rouet, Agnes Mazot)
Session 16: Weathering, Climate, Tectonics and Surface Processes
• 16c: From Source to Sink: Tracing Organic Matter Transport in Fluvial Watersheds to Identify Links and Feedbacks between Climate, Tectonics, Weathering and the Carbon Cycle (Conveners: Miguel Goni, Dirk Sachse, Timothy Eglinton, Valier Galy)
• 16d: Quantitative Links between Tectonics and Surface Processes (Conveners: Jane Willenbring, Frédéric Herman)
• 16f: Terrestrial and Marine Records of Surface Processes (Past and Present) (Conveners: Sunil Singh, Sambuddha Misra)
See below for more details on sessions of specific interest:
07f: Geologic and Geochemical Processes at the Plate Interface
Conveners: Sarah Penniston-Dorland, Christy Till, Taras Gerya
Keynote: Horst Marschall (WHOI)
The subducting slab undergoes significant physical and chemical changes as it enters the mantle and gets into contact with the hot mantle wedge. A series of progressive metamorphic reactions causes rapid changes that are directly related to the release of volatiles to the overriding mantle wedge. The processes at the plate interface directly contribute to the generation and modification of the continental crust as well as the long term evolution of the Earth’s mantle. We invite contributions from researchers who study the nature of the subducting slab near the plate interface. Approaches include the study of exhumed terranes, thermal-petrological modeling of the conditions of the plate interface, geochemical approaches to determine the chemistry of metamorphism and volatile release, and physical studies that determine the structure of plate interface and causes for intermediate-depth seismicity.
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06c: Putting the Little “t” in P-T-H2O-T: Novel Integrations of Geochronology and Thermodynamics in Diverse Tectonic Regimes
Conveners: Ethan Baxter, Michael Williams, Stacia Gordon, Clare Warren, Emilie Janots
Keynote: Matthew Kohn (Boise State)
Advances in geothermometry, geobarometry, and geochronology tend to coincide with advances in both analytical and interpretational (e.g. modelling) techniques. Direct integration of thermodynamic considerations with geochronological data have proven important in reconstructing the evolution of the crust and lithosphere. Important challenges in linking ages to processes & conditions remain, including: 1) the P-T-t evolution of prograde tectonometamorphic processes, 2) the quantification of brief P-T excursions or events, including the role of fluids, 3) the recovery of P-T-t data and paths in high-temperature settings, and 4) the unraveling of complex non-monotonic P-T-t paths. This session will highlight novel contributions to the methodologies and applications of integrated thermodynamic and geochronologic data that help provide better age constraints on the cooking, squashing, shearing, and fluid-related chemical processes that take place from the near-surface to the roots of multiple tectonic settings, including orogens and subduction zones.
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06e: The Dynamic Margins of Continents
Convenors: Oliver Jagoutz, Mark Behn, Mihai Ducea, Peter Clift
Continents grow by magmatism and accretion, differentiate as they grow, and are lost to the mantle by delamination, subduction, erosion. Most of these processes take place at the interface between the continental crust and its environs. To what extent do these processes balance out and influence one another? What are the dominant processes in cratons and at their dynamic margins and how fast do they proceed? How have they changed through time?
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07a: Geochemical, Petrological, and Physical Controls on Arc Eruptions
Conveners: Caroline Bouvet de Maissoneuve, Philipp Ruprecht, Tom Shea
Eruptions at arc volcanoes vary widely in magnitude and in style from effusive lavas and domes to explosive blasts and sustained plinian columns, and eruptive activity can transition between end-member styles during a single unrest period. Eruptive behavior is largely controlled by processes affecting the magma system at depth. Arc magmas, initially supplied from the mantle, often reside and evolve within the shallow crust for extended times before their final ascent towards the surface, during which they may crystallize, vesiculate, assimilate foreign material, as well as mix with other magmas. Such processes constantly redefine the physical state of magmas (geochemical constituency, P-T-fO2 conditions, viscosity, and many more), which ultimately determines their eruptive style (e.g. open vs. closed system behavior). Outstanding issues remain unresolved for arc eruptions: What controls open and closed-system behavior, and are there systematic transitions or cycles between these modes? How frequently do recharge magmas perturb evolving magma reservoirs and in what volumes? What are the timescales required for eruption triggering and the associated processes? How closely are degassing and crystallization linked in the reservoir and during ascent? At which depth level is the fate of the eruption determined – do conduit dynamics or the state of the magma prior to ascend control the eruptive behavior? This session encourages diverse contributions ranging from case studies of historic and prehistoric eruption products to advanced numerical models of magma reservoirs, conduits, and eruptions, with the unifying theme of seeking to understand controls on arc eruptive styles.