Storm-dominated Lower Cambrian depositional environments in the Ravenswood area, Lander County, Nevada
A Lower Cambrian sedimentary sequence 40 meters thick is exposed in the Ravenswood area, Lander County, Nevada. This sequence is divided into 7 lithofacies which are interpreted to represent marine, littoral to sublittoral environments including offshore bars, sheet deposits (proximal, intermediate, distal), patch reefs, and storm-surge ebb channels; The lithology, paleontology, and sedimentary structures reflect deposition in a wave-dominated or storm-dominated system. Paleocurrent indicators suggest that strong westerly (present orientation of continent) winds created landward-directed currents transporting carbonate debris from the shelf to nearshore environments. Subsequently, storm-surge-ebb flows transported nearshore sediments seaward; The lithofacies presented herein indicate that sediments were composed of mixtures of carbonate and siliciclastic material during deposition. The processes responsible for this mixing are punctuated mixing (occurred as a result of storm-transported carbonate sediment into a clastic environment), and facies mixing (occurred with the forming of archaeocyathan bioherms). These bioherms are interpreted to have formed as isolated patch reefs in a sublittoral environment.
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