Depositional Cycles, Diagenesis and Composite Sea Level Changes in Platform Carbonates of the Alpine Triassic

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Shallow water carbonate deposits typically were deposited episodically at the meter-scale in the frequency range of 104-105 years. The proposed research will increase our understanding of the origin and significance of this stratigraphic cyclicity, using the superb exposures of Triassic carbonates in the Alps as natural field laboratories. Earlier work has demonstrated that composite eustatic sea level changes with Milankovitch periodicities played a fundamental role in the cyclical deposition of these Triassic carbonates. The research will attempt, by careful field and laboratory study of the sedimentology, diagenesis and stratigraphy of a spectrum of Alpine Triassic carbonates, to extend this early work to bridge the gap between high frequency meter-scale cyclicity (104-105 year) and the much larger 3rd order scale (106 year) depositional cycles that are the fundamental units of both seismic and sequence stratigraphy. If the response of shallow water carbonates (which are reliable sea level gauges) to the interaction of composite 104, 105 and 106 year sea level cycles, subsidence, and sedimentation can be predicted (or at least understood), then we will have a powerful tool for use in stratigraphic correlation, chronostratigraphy and sequence stratigraphy at an outcrop or borehole core scale finer than that detectable by current seismic stratigraphic methods. Such information would have obvious value in the exploration for hydrocarbon reservoirs and hydrothermal ore deposits that are so commonly hosted in shallow water carbonate deposits.