Geological studies support the interpretation that northern Panamint Valley and Saline Valley, southeast California, form paired pull-apart basins on opposite sides of the right-slip Hunter Mountain Fault Zone. Eight to ten km of late Cenozoic net slip can be established on the Hunter Mountain Fault Zone. Palinspastic reconstruction of northern Panamint Valley indicates that the valley was formed by movement on a shallow crustal, low-angle normal fault of 0--15 degree west dip during the last 3.0 Ma. This interpretation appears to contradiction the notions that little extension is accomodated in the uppermost crust by low angle faulting and that the most recent extension in the Basin and Range Province is accomodated exclusively by high-angle faulting. Saline Valley, however, is interpreted to have formed by extension on closely spaced, rotated planar normal faults. Thus, within one geometric system of paired pull-apart basins, extension appears to have been accommodated in the shallow crust in two different ways. ¿American Geophysical Union 1987 |