HR: 1340h
AN: T33C-1480    [Abstracts]
TI: Depth to Detachment Estimates for the Tanos and West Tanos Faults, Hagen Embayment, New Mexico
AU: * Popek, M A
EM: maggiepopek@gmail.com
AF: The Pennsylvania State University, 307 Deike Building Department of Geosciences The College of Earth and Mineral Sciences The Pennsylvania State University, University Park, PA 16802,
AU: Mitra, G A
EM: mitr@troi.cc.rochester.edu
AF: University of Rochester, Department of Earth and Environmental Sciences 227 Hutchison Hall, Rochester, NY 14627,
AU: Biehler, S A
EM: biehler@ucr.edu
AF: University of California-Riverside, Department of Earth Sciences Geology Building, Riverside, CA 92521,
AU: McPhee, D K
EM: dmcphee@usgs.gov
AF: United States Geological Survey, 345 Middlefield Rd, Menlo Park, CA 94025,
AU: Sussman, A
EM: spring@lanl.gov
AF: Los Alamos National Laboratory, Geophysics, MS D443, Los Almos, NM 87545,
AB: The Hagen embayment is part of the Albuquerque basin, one of the four large basins in the northern portion of the north-northeast trending Rio Grande rift. While the Albuquerque basin has been studied in the search for hydrocarbons, little is known about the relatively shallow Hagen embayment, which consists of several down to the northwest, northeast-striking normal faults, including the Tanos and West Tanos faults. The strike of these and other faults in the Hagen embayment are suggestive of transverse structures such that the embayment acts as an accommodation zone. In an attempt to resolve the subsurface geometry of the Tanos and West Tanos faults and to constrain the structural context of the Hagen embayment, geologic models were constructed along three transects using well data, existing cross-sections, regional geologic information, and gravity data that were collected over several years of the SAGE (Summer of Applied Geophysical Experience) program. A three- dimensional depth-to-Precambrian crystalline basement inverse model created during SAGE 2006 was used to plot the basement contact for the subsurface models. Given the change in thickness of the middle to late Miocene Blackshare Formation along the transects, greater bedding dips in the hanging walls of the Tanos and West Tanos faults than in their footwalls and a decrease in bedding dips upsection, it is hypothesized that the Tanos and West Tanos faults are growth faults. Depth to detachment levels are calculated and used to try to constrain the fault geometry and their broader context. The results of subsurface modeling and depth to detachment calculations suggest that the Tanos and West Tanos faults detach either at the Precambrian crystalline basement contact (approximately 2.5 km below the surface) or at a shallower level (approximately 1.15 km depth). The acquisition of more geophysical data in the Hagen embayment will help elucidate the geometry of the Tanos and West Tanos faults, and allow us to determine the role the embayment played in the development of the Rio Grande rift.
DE: 1200 GEODESY AND GRAVITY
DE: 8000 STRUCTURAL GEOLOGY
SC: Tectonophysics [T]
MN: 2007 Fall Meeting