HR: 0800h
AN: T31A-1258 [Abstracts]
TI: Speculations on the Evolution of the East California Shear Zone and Associated Structures by Fault
Propagation: Comparison with the Mechanics of Anatolia and the Aegean
AU: * King, G C
EM: king@ipgp.jussieu.fr
AF: Laboratoire Tectonique, IPGP, 4 place Jussieu, paris, 75252
France
AU: Friedrich, A
EM: anke@geo.uni-potsdam.de
AF: Institut fr Geowissenschaften Universitt Potsdam, Karl-Liebknechstr. 24/H25, Golm, 14476
Germany
AU: Armijo, R
AF: Laboratoire Tectonique, IPGP, 4 place Jussieu, paris, 75252
France
AU: Gaudemer, Y
EM: dbowman@fullerton.edu
AF: Laboratoire Tectonique, IPGP, 4 place Jussieu, paris, 75252
France
AU: Bowman, D
EM: dbowman@fullerton.edu
AF: Dept. of Geological Sciences, California State University, Fullerton, CA 92834-6850
United States
AB:
Studies of the North Anatolian Fault System (NAFS) in Turkey and Greece have shown that it has evolved by slow growth
(propagation) over millions of years. The system initiated about 13 Myrs ago in eastern Turkey as a result of the collision
of Arabia with Asia. After crossing north Anatolia it reached the Marmara Sea in western Turkey 6 Myrs ago before extending
into the Aegean. Prior to the arrival of the NAFS the Aegean had experienced slow extension for more than 15 Myrs. The
compressional deformation field associated with the NAFS on its south-eastern side suppressed Aegean extension to the
southeast of the fault. To the northwest increased extension rates resulted in the rapid opening of the North Aegean Trough
and the Gulf of Corinth over the last 1Ma.
A similar sequence of events can be proposed for the western USA. By about 5 Ma the southern San Andreas had jumped inland
allowing the Gulf of California to open, creating the big bend and uplifting the Transverse Ranges. At about this time the
Garlock fault propagated to the east reaching the present Owens, Panamint and Death (OPD) Valleys about 3 Ma. Prior to the
arrival of the Garlock fault the Basin and Range had been subject to extension for about 20Ma. The processes of propagation
suppressed extension south of the Garlock fault east of the present Mojave, and enhanced activity in the OPD valleys. This
extension was associated with the onset of volcanic activity and as the extension propagated to the north volcanism appeared
in the Mammoth lakes region about 1-2 Ma.
Except for the extensive volcanism, the evolution is very similar to that observed in the Aegean. However the OPD faults and
their associated mantle structures once formed became activated in shear associated with the American-Pacific Plate boundary
at about 1 Ma. A new episode of propagation ensued with shear deformation extending south into the Mojave block and north to
rejuvenate or enhance extension in the Carson Sink Dixie Valley region.
DE: 8010 Fractures and faults
DE: 8107 Continental neotectonics
DE: 8110 Continental tectonics--general (0905)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting