Start Date/Time: Monday, May 12, 2014, 12:30 PM
Ending Date/Time: Monday, May 12, 2014, 1:30 PM
Location: 123 MSB
Speaker: Andre Droxler, Rice University Dept of Earth Sciences
Title:Deglacial origin of barrier reefs
Abstract: Because the initial phase of barrier reef evolution is often buried under more recent phases of coralgal growth, the origins of modern barrier reefs have remained elusive. Direct observations on the nature of the substrate on top of which barrier reefs have developed are lacking, and simple questions about whether the substrate contributes to their overall linear morphology have remained unanswered. We present here a review dedicated to late-Quaternary shelf-edge deposition in tropical mixed siliciclastic-carbonate systems. These modern analogs are used to develop a quantitative understanding of shelf edge barrier reef formation during different segments of relatively well established sea-level cycles. The onset of rapid sea-level rise during early deglaciations, when siliciclastics were deposited along newly formed coasts at up-dip positions, provided opportune time windows for coralgal communities to establish themselves on top of maximum lowstand siliciclastic coastal deposits, such as beach ridges and lowstand shelf-edge deltas.