Abstract: Fault Kinematics of the Northwestern End of the Whittier Fault in the Northeastern Los Angeles Basin

HERZOG, D. W., and R. S. YEATS, Department of Geosciences, Oregon State University, Corvallis, OR 97331

In the late Miocene and early Pliocene, two low-amplitude anticlines formed in the Whittier oil field area at the west end of the Puente Hills. The Rideout Heights anticline that trends northwesterly from the mouth of Turnbull Canyon through Rideout Heights, caused upper Puente and lower Fernando sands to lens out toward the fold axis. Subsequently, this fold was cut along its axis by the Whittier fault. Strata are overturned southwest of the fault, and normally dipping northeast of the fault. The 184 anticline is located to the southeast and trends N75W. Recent strike-slip on the Whittier fault is accompaniecl by reactivation of the 184 anticline, causing uplift in the footwall block south of Turnbull Canyon. North of Turnbull Canyon, the Whittier fault is at the range front with no evidence of Quaternary footwall uplift, indicating that the overturned limb of the Rideout Heights anticline is part of an inactive structure. Active fault traces, possibly strike-slip, are on or near the Whittier fault south of Turnbull Canyon, but to the north, recent offsets appear to be northeast of the Whittier fault in the Puente Hills. These offsets may represent an attempt of the fault to bypass a restraining bend at Turnbull Canyon. If so, this movement is too recent to offset conglomerate beds more that a few tens of meters. Some evidence cited for recent offsets north of Turnbull Canyon could also be explained by the change in strike of the strata from eastwest to northwest-southeast of the northeast limb of the Rideout Heights anticline.

AAPG Search and Discovery Article #90935©1998 AAPG Pacific Section Meeting, Ventura, California