Cenozoic Geologic Evolution of the Belize Central Continental Margin: Long-Lived Offshore Isolated Carbonate Platforms Versus Juvenile Barrier Reef

Abstract

Abstract

The late Paleocene and NNE-translation of the Caribbean plate and its interaction with the Yucatan margin formed several NNE-oriented, elongated, and isolated tectonic highs along the central Belize margin. On top of these highs, several carbonate platforms, among them Lighthouse, Glovers, Turneffe, and Camel Hump were established sometime in the Oligocene and thrived during the early Miocene. The reliefs of Camels Hump and Glovers platforms, enhanced during the middle/late Miocene by a strike slip fault possibly resulting from the interaction of the Caribbean against the North American plate, triggered the partial collapse of their margins, shedding massive volumes of gravity flows into the intervening Gladden Basin. Soon after, massive deposition of siliciclastic sediments, eroded from the newly formed Maya Mountains onshore, prograded into and infilled the proximal Camels Basin.

Starting at about 3.5 my ago, a series of significant and systematic sea level fall events produced a downward shift of the eastward siliciclastic progradation along the eastern flank of Camels Hump and northern Camels Basin where the coastal and fluvio deltaic deposits were redistributed by alongshore currents into beach ridges. Further west, a fluvial plain formed throughout the area of the present shelf lagoon. During several relatively brief sea level rise intervals in the late Quaternary, in particular an initial and very marked mid-Brunhes (∼0.45 my) re-flooding event, the former lowstand shoreline shifted a considerable distance to the west, whereby siliciclastic sediments remained confined along the newly coast by alongshore currents, promoting offshore the establishment of the Belize Barrier Reef, as we know it today, through the initial growth of coralgal reef accumulation over preserved lowstand topographic positive reliefs such as paleo fluvio deltaic highs, channel levees, and beach ridges.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016