Jelly Bean conglomerate (lower Permian): record of a forebulge in southeastern Arizona
The most incongruous stratigraphic unit the Earp Formation (Pennsylvanian-Permian) is the Jelly Bean conglomerate (JBC), a unit rarely more than 5 m thick, but occurring over 15,000 km/sup 2/. The JBC consists mostly of clast-supported chert-pebble and limestone-clast conglomerate, litharenite, and pebbly sandstone, whereas most of the Earp Formation is marine limestone, siltstone, and shale. The JCB lies on eroded siltstone or limestone, and is capped conformably by siltstone. The JBC is probably a braided-stream deposit as indicated by presence of fluvial dunes and ripples, amalgamated bar and channel conglomerates, imbricated clasts, channeled underbeds, and lack of point bars. Paleocurrents were generally southward. The thinness and widespread occurrence of the JBC suggest a uniform, gentle paleoslope down which the streams flowed. Deposition of the JBC occurred at about the climax of the Marathon phase of the Ouachita orogeny in west Texas and northern Mexico. The age and location of the JBC, which fringes cratonic North America, indicate that it was related to the late Paleozoic convergence of North and South America, and may have resulted from flexural forebulging caused by thrusting in the Marathon orogene and associated sedimentation in a foredeep.
- Research Organization:
- Univ. of Arizona, Tucson
- OSTI ID:
- 5992636
- Report Number(s):
- CONF-8506201-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 69:5; ISSN AAPGB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
ARIZONA
CARBONATE ROCKS
CONGLOMERATES
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
LIMESTONE
NORTH AMERICA
PALEOZOIC ERA
PENNSYLVANIAN PERIOD
PERMIAN PERIOD
ROCKS
SEDIMENTARY ROCKS
STRATIGRAPHY
USA