Depositional environments, diagenesis, and burial history of the Antelope Valley Limestone (Lower-Middle Ordovician) in the Great Basin, central Nevada. (Volumes I and II).
Item
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Title
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Depositional environments, diagenesis, and burial history of the Antelope Valley Limestone (Lower-Middle Ordovician) in the Great Basin, central Nevada. (Volumes I and II).
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Identifier
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AAI9325114
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identifier
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9325114
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Creator
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Kaya, Ali.
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Contributor
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Adviser: Gerald M. Friedman
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Date
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1993
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Language
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English
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Publisher
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City University of New York.
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Subject
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Geology | Geochemistry
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Abstract
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In central Nevada, the Lower Middle Ordovician Antelope Valley Limestone (AVL) resulted from the vertical and progradational growth of Nuia, Girvanella oncolitic, and oolitic- and skeletal shoals.;Energy level of Nuia shoals was higher than that of Girvanella oncolitic shoals.;Nine evolutionary phases of the Whiterockian carbonate platform were recognized. They show "keep up", "incipient drowning", "off lap", and "onlap" shelf-margin features and correspond to three transgressions, two regressions, and two stand-stills.;Glacioeustacy-induced shallowing-upward cycles had an average cycle duration of 82000 yrs.;The Copenhagen Formation is the lagoonal facies of the AVL.;{dollar}\delta\sp{18}{lcub}\rm O{rcub}{dollar} values ({dollar}-{dollar}6.66 to {dollar}-{dollar}6.77{dollar}\perthous{dollar} PDB) of radiaxial-fibrous and columnar calcites (marine cements) are consistent with the estimated-{dollar}\delta\sp{18}{lcub}\rm O{rcub}{dollar} values of the Middle Ordovician marine calcite.;Meteoric calcite cements, volumetrically the most important cement type in the AVL, formed during major progradations.;Void- and fracture-filling calcite cements (FFCC), having more depleted-{dollar}\delta\sp{18}{lcub}\rm O{rcub}{dollar} compositions than those of marine calcites in the AVL, are deep burial in origin. However, a late FFCC with exceedingly depleted-{dollar}\delta\sp{18}{lcub}\rm O{rcub}{dollar} composition ({dollar}-{dollar}18 to {dollar}-{dollar}30{dollar}\perthous{dollar} PDB) and low-salinity fluid inclusions indicates a composition of meteoric water.;Nine kinds of multistage dolomitization were identified in the AVL: Dolomite I (marine dolomite); Dolomite II (supratidal dolomite); Dolomites III, IV and V (formed in a shallow to intermediate-burial depth); and Dolomites VI, VII, VIII, and IX (late-diagenetic, deep-burial in origin). Dolostones (Dol. VII) of the AVL originated from two unknown basinal brines.;Dedolomitization of the AVL reflects late, near surface diagenesis.;Non-stoichiometric Dolomite II suggests that time has no direct control over dolomite stoichiometry.;Biologic opal-A was the source of silica in chert nodules. Cathodoluminescence study suggests that opal-CT transformation to quartz released Mg and caused dolomitization at the margin of chert nodules.;Results of multi-geothermometry suggest 7 to 10 km of burial depth and 9 to 12 km of total uplift for the AVL, which are consistent with the reconstructed subsidence curve.;Fluid-inclusion microthermometry and illite crystallinity have advantages over using both TAI of organic matter and oxygen-isotope thermometry for determining the maximum burial temperature of the AVL.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
