TECTONIC AND GEOMETRIC CONSTRAINTS FOR THE WIND CANYON BLOCK ON THE SOUTHEASTERN SIDE OF THE GARLOCK FAULT FROM APATITE FISSION TRACK ANALYSES

New apatite fission track analyses from the southeastern side of the Garlock fault near Mojave, CA were obtained in order to better understand the fault evolution and tectonics of the region. The events that formed the western Mojave desert and Tehachapi Mountains near the Garlock fault are poorly constrained. Apatite fission track analyses are commonly used to date the timing of exhumation of orogenic belts and can be used to constrain the geometry of fault blocks. Based on geomorphology, the study area appears to include an uplifted fault block, which is ~13 km in length parallel to, and ~5 km in width perpendicular to, the Garlock fault; we will refer to it here as the Wind Canyon block. The convex shape of the southeastern margin of the Wind Canyon block suggests that it is bounded to the southeast by either a southeast-vergent thrust fault or a normal fault. Our initial apatite fission track ages from granitoids within the fault block are 51 to 31 Ma. These ages are intermediate between the youngest and oldest apatite fission track ages from the Tehachapi mountains (Blythe and Longinetti, 2013) immediately to the north of the Wind Canyon fault block. Our initial interpretation is that Wind Canyon fission track ages are consistent with partial resetting by exhumation along the Wind Canyon fault during Miocene time. Different tectonic scenarios will be further evaluated with these new data.