Location: Sacramento Convention Center, Sacramento, California, USA
Web: http://goldschmidt.info/2014/index
Includes the following sessions:
02c: Compositions of the interiors of the terrestrial planets - causes and consequences
Convenors: James Day (jmdday@ucsd.edu), Radjeep Dasgupta (radjeep.dasgupta@rice.edu)
Planetary interior compositions are fundamentally controlled by the material accreted to form a planet and the physical processes of differentiation. This session aims to draw together experimental petrologists, geochemists, and modelers to discuss the interior compositional constraints for rocky Solar System planets. Topics of interest include - but are not limited to - constraints on the planetary interior compositions based on geophysical and geochemical observations, relative contributions of accretion, magma ocean differentiation versus late, heavy bombardment on the volatile and other trace element budgets and redox state of bulk mantle, the presence and causes of lithologic heterogeneities in mantles, and compositional controls on physical processes occurring on planetary bodies (c.f. plate tectonics, plumes).
05e: Intra-plate magmatism from recycled crust and mantle
Convenors: Andreas Stracke (stracke.andreas@uni-muenster.de), John Lassiter (lassiter1@mail.utexas.edu)
The origin and magnitude of mantle heterogeneity is governed by the nature, extent, and timing of geochemical cycling between the planets’ major silicate reservoirs: the crust, lithosphere, and mantle. The spatial scale and distribution of the geochemically and lithologically diverse materials in the Earth’s mantle is thereby determined by the fluid dynamics of mantle convection. During intra-plate magmatism, partial melting preferentially samples geochemically enriched source components. These enriched components likely represent a variety of materials that have been recycled into the mantle and distributed heterogeneously by a range of mechanisms over Earth’s history. The enriched geochemical signatures observed in intra-plate volcanic rocks may therefore identify the large-scale geochemical processes responsible for continuous silicate Earth differentiation. This session welcomes innovative contributions employing a broad spectrum of analytical and computational methods to study the origin, mode of sampling, and length scale of mantle heterogeneities sampled by intra-plate magmatism.
06a: The scum of the Earth - the composition of the continental crust and mechanisms for its production through time
Convenors: Catherine Chauvel (catherine.chauvel@ujf-grenoble.fr), Roberta Rudnick (rudnick@geol.umd.edu), Bruno Dhuime (b.dhuime@bristol.ac.uk), Oliver Jagoutz (jagoutz@mit.edu)
Mantle melting produces basalts but the continental crust is andesitic on balance. Petrology, geochemistry, geodynamics and geophysics provide insights into how continental crust is extracted from the mantle. In spite of great progress in these fields, the process of crust formation is still enigmatic to a significant extent. How is continental crust made and differentiated? What is our best estimate of continental crust? Why does the crust appear andesitic on average if mantle melting appears to produce basalt? This session is devoted to cross-pollination and integration for the purpose of progressing research in crustal petrogenesis.
Keynote: Peter Cawood (University of St Andrews, UK)
06b: The supercontinent cycle
Convenors: John Goodge (jgoodge@d.umn.edu), Peter Cawood (pac20@st-andrews.ac.uk), Wouter Bleeker (wouter.bleeker@nrcan.gc.ca), Adam Maloof (maloof@princeton.edu)
Supercontinents come and go, causing massive shifts in continental climate, biotope, and geodynamic systems. The episodic existence of supercontinents exerts a fundamental control on secular changes in the Earth system, and may reflect a deeper geodynamic periodicity. This session aims to bring together geodynamicists, petrologists, biogeochemists, sedimentologists, and economic geologists to explore the full spectrum of causes and consequences of supercontinent formation. We propose to focus attention on episodicity gleaned from the geochronological record to assess tectonic and environmental process associated with supercontinent formation over time. How much new crust is generated? Is it long-lived? What mechanisms are involved in supercontinent assembly? How is supercontinent amalgamation manifested by mineral deposits? What are the implications of supercontinent formation on environmental systems in the continental realm? What biogeochemical feedbacks are there between the continents, atmosphere and oceans that influence development of living systems? What’s happening across the remainder of the non-amalgamated surface system (oceans)? What are the effects of supercontinent assembly on seafloor dynamics? How are deep-earth and near-surface processes linked in the deep geologic past? In general, the session will focus on supercontinent assembly, rather than breakup, and the implications of supercontinent formation for geodynamic process, crustal growth history, geochemical and paleoenvironmental linkages across the continent-atmosphere-ocean system, mineral deposit distributions, and periodicity.