Sedimentology and depositional architecture of the Cayman (Miocene) and Pedro Castle (Pliocene) formations on western Grand Cayman, British West Indies.

摘要

Seven drill cores on western Grand Cayman record the Cayman (middle to late Miocene) and Pedro Castle (Pliocene) Formations. The preserved Cayman Formation is comprised of two units deposited in shallow water 10--30 m deep. The two units represent two distinct depositional regimes controlled primarily by relative water energy. The Cayman Formation in the study area has an overall muddier texture than other Grand Cayman and Cayman Brac study areas.; Terminal Miocene lowstand conditions resulted in partial removal of the upper Cayman Formation on Grand Cayman. The topography of this unconformity controlled water depths and partially restricted circulation during deposition of the Pedro Castle Formation. Up section decreases in energy levels reflect a gradually increasing relative sea level. Laterally extensive facies with a defined vertical succession indicate that similar shallow water depositional conditions existed throughout western Grand Cayman. Dolomite content in the Pedro Castle Formation consistently decreases upsection.