HR: 08:45h
AN: T41C-04    [Abstracts]
TI: Thermo-Kinetic Interpretative Model for Couple Basement-Detrital Thermochronology
AU: * Lovera, O M
EM: lovera@ucla.edu
AF: UCLA, Dept. Earth and Space Sciences, Los Angeles, CA 90095, United States
AU: Grove, M
EM: marty@ess.ucla.edu
AF: UCLA, Dept. Earth and Space Sciences, Los Angeles, CA 90095, United States
AU: Kohn, B
AF: The University of Melbourne, School of Earth Sciences, Parkville, NSW 3052, Australia
AU: Fletcher, J
AF: CICESE, Departamento de Geologia, Ensenada, BC , Mexico
AU: Kimbrough, D
AF: San Diego State University, Department of Geological Sciences, San Diego, CA 92182- 1020, United States
AU: Umhoefer, P
AF: Northern Arizona University, Department of Geology, Flagstaff, AZ 86011, United States
AU: Schwennicke, T
AF: UABCS, Departamento de Geologia Marina, La Paz, BC , Mexico
AU: Gleadow, A J
AF: The University of Melbourne, School of Earth Sciences, Parkville, NSW 3052, Australia
AB: Clastic sedimentary sequences shed from orogenic belts provide a fertile, and arguably unique, record of crustal exhumation. However, in spite of the considerable recent analytical advances, interpretive methods for detrital thermochronology have remained relatively basic. There is a clear need for numerical approaches for interpreting detrital thermochronology that are capable of dealing with transient heat flow related to intrusion and faulting and, at the same time, are constructed to appropriately and comprehensively accept input from a variety of thermochronologic constraints. Similarly, there is a need to move beyond simple interpretation of detrital age distributions and employ more informative thermochonometers that are capable of reducing ambiguities in data interpretation that arise in environments with complex thermal histories (such as shallow arc crust). Here we present a general thermo-kinetic model capable of describing rifted arc crust to constrain the initiation time, slip history, and erosion history related to normal faulting by simultaneously fitting detrital and basement thermochronologic data collected within a continental rift setting (Baja California margin of the southern Gulf of California). The San Jose del Cabo (SJDC) normal fault is a major east-dipping normal fault associated the San Jose del Cabo rift basin and mid- to late Cretaceous arc basement (Los Cabos block). Preliminary results indicate that 4-6 of the 10 km total basement denudation is due to Late Miocene-Recent rift-related denudation. Peak exhumation occurred at 7 m.y. at 1 km/m.y. K-feldspar multi-diffusion domain results limit total denudation to 4-6 km and indicate that virtually all slip along the SJDC fault took place after 10 Ma of similar to the age of the oldest known sediments within the SJDC basin.
DE: 1040 Radiogenic isotope geochemistry
DE: 1140 Thermochronology
DE: 4260 Ocean data assimilation and reanalysis (3225)
DE: 8105 Continental margins: divergent (1212, 8124)
DE: 8109 Continental tectonics: extensional (0905)
SC: Tectonophysics [T]
MN: 2007 Joint Assembly