Three extensional basin types associated with detachment-style faulting, early Miocene of the central Mojave Desert

Conference · Thu Apr 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5420051

Fillmore, R P; Walker, J D ^[1]

---

1. Univ. of Kansas, Lawrence, KS (United States). Dept. of Geology

Three distinct extensional basin types, formed synchronously in different structural settings, have been identified in the central Mojave Desert and provide a basis for the paleogeographic reconstruction of extension of the central Mojave metamorphic core complex (CMMCC). From west to east, the Tropico, Pickhandle, and Clews basins formed in the footwall, on the breakaway, and well within the hanging wall of the east-rooting detachment fault system of the CMMCC. The Tropico basin was created by crustal-scale flexure of the little extended footwall behind the breakaway of the detachment. The basin was shallow and areally extensive. Lower strata on the eastern margin comprise fluvial sandstone derived from the adjacent highland; these grade up into lacustrine deposits. The Pickhandle rift basin is a half graben that was bounded to the west by the detachment escarpment. Initially the basin was deep and narrow, and elongate parallel to the detachment. Basin fill consists of megabreccia, conglomerate derived from both the footwall and hanging wall, and synextensional volcanic rocks. The Clews basin developed within the hanging wall, and synextensional volcanic rocks. The Clews basin developed within the hanging wall. Basal lacustrine strata record initial downwarping. The overlying coarsening-upwards clastic sequence, derived from the east, reflects the propagation of a west-dipping normal fault on the east basin margin that is interpreted to sole into the detachment that probably extended beneath the area from the west. Sediment deposited in extensional basins contain a record of early phase extension that is not obtainable by other types of studies. The recognition of footwall-uplift, breakaway rift, and intra-hanging wall basin types in highly extended terranes may aid in the reconstruction of features that have been modified, such as the position of the detachment breakaway zone, and the areal extent of extensional deformation.

• OSTI ID: 5420051
• Report Number(s): CONF-9305259--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:5
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CALIFORNIA
CENOZOIC ERA
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
LAKES
MIOCENE EPOCH
NORTH AMERICA
ORIGIN
SEDIMENTARY BASINS
SEDIMENTS
STRATIGRAPHY
SURFACE WATERS
TECTONICS
TERTIARY PERIOD
USA