Depositional setting and paleogeography of Ordovician Vinini Formation, central Nevada
- California State Univ., Long Beach (United States)
The eugeoclinal strata of the Ordovician Vinini Formation composes most of the Roberts Mountains allochthon (RMA). Its stratigraphy, reconstructed in the Roberts Mountains, can be precisely correlated throughout much of the RMA and into coeval strata of the autochthonous miogeocline by means of graptolite and conodont biostratigraphy. The Vinini is a mixture of clastic lithologies with some limestone and greenstone. Coarse clastics, characterized by well-rounded and well-sorted sands derived from cratonic sources, occur in two separate intervals and provide critical data on depositional and paleogeographic setting. The lower interval, hundreds of meters thick, was deposited in the latest Ibexian-earliest Whiterockian and can be closely correlated throughout central Nevada. It is a mixture of quartz sandstone, siltstone, limestone, and calcareous sandstone, deposited by turbidity flows during a lowstand of sea level. Both eastern and western sources have been interpreted for these sands. The upper interval is a prominent, pure quartzite up to 20 m thick deposited as a prograding blanket of sand in the latest Whiterockian-earliest Mohawkian. It occurs in the Vinini in the northern Toquima Range and in a parautochthonous sequence of transitional strata in the southern Toiyabe Range. This interval represents the most basinward edge of the Eureka Quartzite, which was also deposited across the miogeocline. The presence of sand of the Eureka Quartzite in the RMA indicates that the basin in which the RMA strata were deposited was immediately adjacent to the margin of North America in the Ordovician.
- OSTI ID:
- 5200444
- Report Number(s):
- CONF-9103128-; CODEN: AABUD
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:2; Conference: American Association of Petroleum Geologists (AAPG)/Society of Economics, Paleontolgists, and Mineralogists (SEPM)/Society of Exploration Geophysicists (SEG)/Society of Professional Well Log Analysts (SPWLA) Pacific Section annual meeting, Bakersfield, CA (United States), 6-8 Mar 1991; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GEOLOGIC FORMATIONS
PALEONTOLOGY
STRATIGRAPHY
LIMESTONE
DEPOSITION
NEVADA
CORRELATIONS
GEOLOGIC HISTORY
LITHOLOGY
ORDOVICIAN PERIOD
CARBONATE ROCKS
DEVELOPED COUNTRIES
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGY
NORTH AMERICA
PALEOZOIC ERA
ROCKS
SEDIMENTARY ROCKS
USA
580000* - Geosciences