Late Jurassic extension in the Bisbee basin: Marine and volcanic strata of the Chiricahua Mountains, Arizona

Conference · Wed Mar 31 23:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5019688

Lawton, T F; McMillan, N J ^[1]; Cameron, K L ^[2]

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1. New Mexico State Univ., Las Cruces, NM (United States)
2. Univ. of California, Santa Cruz, CA (United States). Earth Sciences Board

Upper Jurassic strata in the northeastern Chiricahua Mountains provide unambiguous stratigraphic and geographic links between the Chihuahua trough of north-central Mexico and the Bisbee basin of southeastern Arizona. Approximately 1,800 m of limestone, shale, and mafic volcanic rocks overlie the Glance Conglomerate and underlie fluvial redbeds of the Lower Cretaceous Morita Formation. Basal strata are alluvial-fan and sabkha deposits. A thick (150 m), ammonite-bearing black shale interval above the sabkha deposits indicates an abrupt increase of water depths; deepening was accompanied initially by emplacement of subaerial basalt flows and subsequently by deposition of basaltic tuff and pillow lava. Ammonites are present both below and above the tuff and indicate its exclusively subaqueous origin. Arkosic deltaic deposits above the tuff were derived from Precambrian rocks of the footwall block to the northeast. At least 200 m of mafic subaerial flows, previously regarded as mid-Tertiary, overlie the deltaic deposits. The existence of a depleted mantle source beneath the Bisbee basin at 150 Ma suggests a unique tectonic setting that combined backarc and Gulf of Mexico extension.

• OSTI ID: 5019688
• Report Number(s): CONF-9305259--
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:5; ISSN GAAPBC; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ARIZONA
BASALT
DEPOSITION
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
IGNEOUS ROCKS
JURASSIC PERIOD
LAVA
MAGMATISM
MESOZOIC ERA
NORTH AMERICA
PALEONTOLOGY
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
STRATIGRAPHY
TECTONICS
TUFF
USA
VOLCANIC ROCKS