Detached strata in a Tertiary low-angle normal fault terrane, southeastern California: a sedimentary record of unroofing, breaching, and continued slip

Journal Article · Fri Jul 01 04:00:00 EDT 1988 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1988)016<0645:DSIATL>2.3.CO;2· OSTI ID:6821841

Miller, J M.G.; John, B E

Miocene sedimentary strata exposed in the eastern Chemehuevi Mountains, southeastern California, record development of an evolving low-angle normal fault system. The sequence includes more than 1 km of conglomerate and sandstone with rare interbedded monolithologic breccia and volcanic flows. Clasts of Peach Springs Tuff in basal units indicate that this succession is younger than 18 Ma. These rocks have been displaced by a regionally extensive low-angle normal fault, the Chemehuevi detachment, and are folded and faulted. Structural reconstructions and the character of associated fault rocks indicate that the Chemeheuvi fault was initiated at a low angle and that the footwall was progressively unloaded through thinning and displacement of its cover during extensional deformation. The syntectonic sedimentary rocks described here provide evidence that movement continued on the gently dipping (< 15/sup 0/) fault even after part of the fault was breached and the footwall eroded. The Conglomerates and sandstones were deposited by stream flow and debris flow on alluvial fans. Synsedimentary faulting is suggested by angular discordance below one monolithologic breccia bed and by local coarsening-upward sequences. Clast types reveal progressive unroofing of hanging-wall rocks to exposer the Chemehuevi fault zone, from which chloritic, brecciated granite clasts were derived. Clasts were then derived from both the hanging wall and the footwall, footwall debris being dominant high in the section. Distinctive clasts show that late displacement on this evolving fault system was on the order of 1 to 5 km.

• Research Organization: Vanderbilt Univ., Nashville, TN (USA)
• OSTI ID: 6821841
• Journal Information: Geology; (United States), Journal Name: Geology; (United States) Vol. 16:7; ISSN GLGYB
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology &amp; Hydrology-- (-1989)
AGE ESTIMATION
ALLUVIAL DEPOSITS
CALIFORNIA
CENOZOIC ERA
DEFORMATION
DEPOSITION
EROSION
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
IGNEOUS ROCKS
MIOCENE EPOCH
MOUNTAINS
NORTH AMERICA
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SLIP
STREAMS
SURFACE WATERS
TECTONICS
TERTIARY PERIOD
TUFF
USA
VOLCANIC ROCKS