Tertiary basin evolution, eastern Mojave Desert
Abstract
Tertiary sedimentary rocks of the Old Woman Mountains region of southeastern California were deposited in isolated basins whose formation was influenced by a regime of detachment faulting. Fourteen lithofacies occur in the region within two major depositional settings--a volcanic center setting and a basement block-adjacent setting. Basin filling in the Little Piute, Piute, Ship, and northern Old Woman Mountains was synchronous with the uplift and unroofing of the Old Woman Mountains structural block. Block uplift was nonuniform, progressing from south to north over time. Sediments in the Stepladder and Marble Mountains were deposited within volcanic centers while strata in the Clipper Mountains were deposited on the periphery of a volcanic center. Controls on individual basin evolution were varied. The Ship Mountains basin developed by simultaneous fault block rotation and Old Woman Mountains uplift. The Little Piute Mountains basin was controlled only by uplift of the Old Woman Mountains block until the initiation of fault block rotation in post-18 m.y. time. Gradual westward accretion of the Whipple Detachment Terrane headwall fault onto the Old Woman Mountains block is inferred. Faulting was not a significant factor in the development of the Piute and northern Old Woman Mountains. Basins of these ranges formed mainly under a regime of gradual uplift of the Old Woman-Piute Mountains block. The main control on basin evolution in the Stepladder, Marble, and Clipper Mountains was crustal fracturing and the subsequent extrusion of volcanic material. A megabreccia unit within the Tertiary sedimentary sequence in the Ship Mountains is interpreted as of landslide origin. It occurs at an angular unconformity in the sequence, indicating two major phases of fault block rotation in the Ship Mountains area. The first phase of fault block movement in the range occurred before approximately 18 m.y.
Subject Area
Geology
Recommended Citation
Knoll, Martin Albert, "Tertiary basin evolution, eastern Mojave Desert" (1988). ETD Collection for University of Texas, El Paso. AAI8911140.
https://scholarworks.utep.edu/dissertations/AAI8911140