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Detrital carbonates in a sequence stratigraphic framework: An example from the Furongian slope environment in the hot creek range of central Nevada

Posted on:2013-09-02Degree:M.SType:Thesis
University:University of Nevada, Las VegasCandidate:Taufani, LeonFull Text:PDF
GTID:2450390008981212Subject:Geology
Abstract/Summary:
An integrated sedimentological study of detrital carbonates of the late Cambrian (Furongian) Hales Limestone in central Nevada was conducted in order to model facies distribution and controlling mechanisms of carbonate gravity-flow deposits. Seven closely-spaced sections and numerous traceable short sections were measured to investigate temporal and spatial changes of detrital carbonates within a high-resolution stratigraphic framework supported by biostratigraphic and carbon isotope chemostratigraphic constraints and by key physical surfaces. Polished slabs and thin section petrographic analysis were used to identify micro- and macro-scale textures and diagenesis.;Ten lithofacies are identified from the Hales Limestone. Lateral tracing of these facies reveals considerable facies variations within a distance of ∼1 kilometer. Such lateral facies variations suggest their deposition in submarine fan systems where localized distributary channels were well developed. Progradation-retrogradation of the carbonate platform is recorded by the abundance of carbonate debris-flow deposits and by thickening- and coarsening-upward trend in background carbonate beds.;Thick intervals of debris-flow deposits contain both platform- and slope-derived carbonate clasts. They were most likely deposited during progradation and exposure of the shelf margin. Sequence and biostratigraphic correlation across the platform-to-basin transect indicates that the major debris-flow breccia units of the Hales Limestone matches well with the relative sea-level fall events recorded in shelf successions. This suggests that the detrital carbonate deposits in slope-basinal environments of the Furongian-early Ordovician platform were mainly controlled by relative sea-level changes. This interpretation is consistent with a global sea-level curve constrained by bio- and chemostratigraphic data.
Keywords/Search Tags:Detrital carbonates, Hales limestone
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