earthscope north rockies glenn biasi 9/16-18/2005 p.1 great break great basin and range evolution...

EarthScope North Rockies Glenn Biasi 9/16-18/2005 p.1

Great BREAK

Great Basin and Range Evolution and Kinematics

June 21-23, 2004

Granlibakken Resort and Conference Center, Tahoe City, CA


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.


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


~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?


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.


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 non-

uniqueness 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.


Which is stronger? What is the driving force?

Decoupling of crust and upper mantle?

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?


Phil Wannamaker

Magnetotelluric methods complement deep seismic tomography.


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?

Jim Faulds

Walker Lane as a developing plate boundary

Steve Wesnousky

20%


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.

Greg Arehart

Shallow expression of deep-seated processes: relate to resources


Breakouts (Continued)

• Breakout H: Seismic and Geophysical Methods, Crust and Mantle– Three projects in sub-disciplinary self-

organization. • Promote the use of legacy data and models.

• Develop a test site or proving ground

• Immediate need for a community modeling environment (CME).


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


• Look forward to surprises…


Smith et al, 2004

Example of discovery, first shown at GREATBREAK

30 km0

27-32 km


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


The voyage to understanding… it’s a slow trip

Teacher WorkshopsLas Vegas/Reno

Sumatra earthquake Bishop Manogue High School Station.

Sensor VaultInstallation 6/04

Nevada K-12 Seismology Program


Karl Karlstrom

earthscope north rockies glenn biasi 9/16-18/2005 p.1 great break great basin and range evolution...

Documents

great basin deformation

cathemethe great basin

great breakgreat basin

northern basin

upper mantle

western great basinwhat

range province

relevant mantle processes