Effects of Older Crustal Structures on Passive Margin Sedimentation: Lower Cambrian Zabriskie Quartzite (Southwestern Great Basin, California-Nevada) as an Example
Anthony R. Prave
The Zabriskie Quartzite is a relatively thin (0-250 m), laterally persistent, mature unit that is exposed throughout the Death Valley region of California and Nevada. Thirty-eight sections were measured in detail. Six facies were described and used to infer a progradational-transgressive succession. Lateral facies changes are gradual and paleocurrent indicators record only north-northwest transport directions. Thus, a uniform paleoslope can be inferred. This, coupled with the lateral continuity and quartz arenitic composition, indicates passive-margin sedimentation. However, the Zabriskie also exhibits relatively large, lateral thickness changes that can be attributed to small differences in subsidence rates at the time of deposition. The thickened and thinned sections co respond to upper Proterozoic basins and highlands that formed during the rift-dominated phase of the late Proterozoic margin of North America. Thus the Zabriskie contains sedimentologic evidence for the change from a rift-dominated to a passive margin-dominated tectonic phase, a conclusion in agreement with published tectonic subsidence curves.
AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.