| Most studies of Caribbean carbonate deposits measure sea level in relation to established highstands. In this study, however, examination of the Ironshore Formation on Grand Cayman revealed a succession of 6 units (A, B, C, D, E, and F) whose deposition ages correlate to transgressive-regressive sea level cycles. The two youngest units, E and F, were discovered during the course of this study. Onshore and offshore fossil dates established that Unit D ranges in age from 123 to 147 ka (average133 ka), Unit E from 95 to 110 ka (average 101 ka), and Unit F from 80 to 87 ka (average 80 ka). Unit D was deposited during the transgression that led to the Sangamon highstand. Units E and F were deposited throughout the transgressive and regressive cycles of substages 5c and 5a, respectively. |
