The Bouse Formation and bracketing units, southeastern California and western Arizona: Implications for the evolution of the proto-Gulf of California and the lower Colorado River

Journal Article · Sat Nov 10 00:00:00 EST 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JB095iB12p20111· OSTI ID:5195257

Buising, A V ^[1]

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1. California State Univ., Hayward (USA)

Mio-Pliocene sediments of the lower Colorado River area represent the nothernmost well documented extent of the proto-Gulf of California, a tectonically enigmatic marine incursion that occupied much of what is now the Gulf of California region--including the lower Colorado River area and the Salton Trough--as much as 8 m.y. prior to the onset of spreading-and transform-related subsidence in that area. Syndepositional folding of the Bouse Formation and bracketing units is believed to reflect slumping on oversteepened slopes, perhaps exacerbated by episodic tectonic activity. The Bouse Formation and bracketing units record four stages in the evolution of the northern proto-Gulf/lower Colorado River area: (1) dissection of preexisting, detachment fault-controlled topography and localized, interior-drainage alluvial deposition (about 14-9 Ma); (2) regional subsidence and proto-Gulf transgression (perhaps as early as about 8 Ma; not later than about 5.5 Ma); (3) progradation of ancestral Colorado River delta into the northern end of the proto-Gulf basin (prior to about 4.3 Ma); and (4) arrival of throughgoing Colorado fluvial channel (prior to about 3.5-4 Ma). Outcrop relations between the Osborne Wash strata and the Bouse Formation, and the relationship of these units to modern landforms, indicate that topography in the lower Colorado River area has not changed significantly since middle Miocene time. Subsidence of the Bouse basin is believed to have occurred via broad regional downwarping. Timing suggests that incipient proto-Gulf extension in the lower Colorado River area was arrested by the approximately 5-Ma shift to the modern transtensional regime.

• OSTI ID: 5195257
• Journal Information: Journal of Geophysical Research; (United States), Vol. 95:B12; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ARIZONA
GEOLOGIC FORMATIONS
CALIFORNIA
TECTONICS
AGE ESTIMATION
COLORADO RIVER
DEFORMATION
DEPOSITION
GEOLOGIC FAULTS
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOMORPHOLOGY
GROUND SUBSIDENCE
GULF OF CALIFORNIA
ORIGIN
SEDIMENTARY BASINS
SEDIMENTS
TOPOGRAPHY
DEVELOPED COUNTRIES
FEDERAL REGION IX
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
NORTH AMERICA
PACIFIC OCEAN
RIVERS
SEAS
STREAMS
SURFACE WATERS
USA
580000* - Geosciences