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Great BREAK Great Basin and Range Evolution and Kinematics June 21-23, 2004 Granlibakken Resort and Conference Center, Tahoe City, CA EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.1 Theme • The Great Basin is a type location for the breaking apart of a continent. • Earthscope will be setting a precedent for understanding such processes on a global scale. EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.2 Goals of GreatBREAK • Prepare for EarthScope in the Great Basin • Identify key questions in Basin and Range origin, development and deformation • Explore interdisciplinary solutions geologic, geodynamic, seismic, gravity, magnetotelluric, geochemical EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.3 EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.4 ~85 smiling participants Topical Breakout Sessions • Breakout Theme A: Extensional tectonics on the largest scale – Why does the Sierra Nevada block move? – What is the cause of Great Basin high uplift? present high elevation? – What aspects of lithospheric rheology control Great Basin strength and deformation? • Is it sufficient to consider the strength of the crust, or must problems consider integrated lithospheric strength? – What made the rheology as it is? EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.6 Thatcher, W., G.R. Foulger, J.B. R., J. Svarc, E. Quilty, and G.W. Bawden, Present-Day deformation across the Basin and Range province, western United States, SCIENCE, 283, 1714-1718, 1999. Bennett, R.A., B.P. Wernicke, N.A. Niemi, A.M. Friederich, and J.L. Davis, Contemporary strain rates in the northern Basin and Range province from GPS data, Tectonics, 22 (0278-7407/03/2001TC001355), 3-1 - 3-31, 2003. EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.7 EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.8 Breakouts (continued) • Breakout B: Rheology of the Mantle and its Relation to Current Tectonics; Why Are Some Parts of the Basin and Range More Active than Others – What does Great Basin deformation say about lithospheric rheology? – The role of fluids: Can magnetotellurics reduce nonuniqueness of mantle seismic models? • Breakout C: What is the mantle and lower crust in the Great Basin doing now? – What are the relevant mantle processes? – How are the crust and mantle coupled? • Sierra Nevada drip, delamination • Mantle flow associated with the trailing edge of a subducting slab. EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.9 Decoupling of crust and upper mantle? Which is stronger? What is the driving force? EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.10 Wesnousky presentation Breakouts (continued) • Breakout D: Contrasts between the Eastern and Western Great Basin – What are the geophysical similarities and differences between east and west? – Proterozoic basement underlies the E. B&R, Paleozoic/Mesozoic accreted terrain beneath the west. Where is the boundary? How do older terrain boundaries contribute? – What drives seismicity east of the Wasatch Front? EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.11 Magnetotelluric methods complement deep seismic tomography. EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.12 Phil Wannamaker Breakouts (Continued) • Breakout E: How do faults behave over time? Do they turn on and off, speed up – slow down? If so, why? – Discrepancies between geodetic, geologic, and seismic rates of strain accumulation – Geological study will be needed – Dating and mapping facilities are needed (e.g., the GeoPBO white paper) • Breakout G: Walker Lane. – When did it start? – How does the crust accommodate simultaneous extension and strike-slip deformation in the Walker Lane? EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.13 Walker Lane as a developing plate boundary Jim Faulds 20% Steve Wesnousky Breakouts (Continued) • Breakout F: Relations of Economic Resources to Tectonics (Structure, Magmatism, Fluid and Heat Flow) – Large-scale controls on Eocene mineralization Carlin Au (NNW) and porphyry Cu-Au-Mo (EW) – Industry collaborations could be mutually beneficial. EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.15 Shallow expression of deepseated processes: relate to resources Greg Arehart Breakouts (Continued) • Breakout H: Seismic and Geophysical Methods, Crust and Mantle – Three projects in sub-disciplinary selforganization. • Promote the use of legacy data and models. • Develop a test site or proving ground • Immediate need for a community modeling environment (CME). EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.17 Desired Legacy • Discovery • Community Earth model – Collaboration with SCEC • Invigorated Earth science community (SCEC model) • Scientific understanding of the evolution of the plate boundary and resources (in the broadest sense) in the Great Basin. • GreatBREAK web site (report, science presentations: – www.seismo.unr.edu/greatbreak EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.18 • Look forward to surprises… EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.19 27-32 km 0 30 km Example of discovery, first shown at GREATBREAK EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.20 Smith et al, 2004 Ingredients for Successful Science Integration (Tom Jordan presentation, lessons drawn from SCEC successes) • Problem focus – Regional tectonics & hazards • Common objectives – Community data products & models • Community identity & organization – History of collaboration, interactive working groups • Collaboratory infrastructure – Code validation, standardization of products • Regular forums for assessing progress – Workshops, annual meeting • Funding – To support collaboration/collaboratory activities EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.21 The voyage to understanding… it’s a slow trip EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.22 EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.23 Teacher Workshops Las Vegas/Reno Nevada K-12 Seismology Program Sensor Vault Installation 6/04 Sumatra earthquake Bishop Manogue High School Station. North Rockies KarlEarthScope Karlstrom Glenn Biasi 9/16-18/2005 p.25