Title

Elevated Pleistocene Coral Reefs of Haiti: Uranium Series Dating

Event Name/Location

Geological Society of America Abstracts with Program

Document Type

Conference Proceeding

Publication Date

1981

Abstract

Elevated marine terraces of the Northwest Peninsula of Haiti have been investigated for geologic structure, age, and height above sea level. The terraces are identified as constructional coral reefs each typically containing an Acropora palmata crest facies, lower A. cervicornis facies, and lower or interposed Montastrea annularis facies. Occasionally a beach sandstone facies is present shoreward of the A. palmata zone.

From the town of Mole St. Nicholas 10-25 km eastward, 8 well-defined reefs rise to an elevation of 200m. These are linearly contiguous for at least 10 km and show little evidence of warping or differential uplift. Raised reefs continue at least 60 km eastward to Port-de-Paix and are also exposed on the island of Tortue. Eight additional constructional reef terraces are present from 200-600 m elevation around the area of Mare Rouge. A series of raised reefs are also present along the extreme west coast, Cap St. Nicholas area.

The most prominent terrace cresting at 52 m gives Th-230/U-234 dates on unrecrystallized A. palmata which average 126,000 ±5,000 years B.P. Assuming a sea level of +6 m at 125,000 years ago, the data suggest an uplift rate of .37 m/1,000, making the Northwest Peninsula area of Haiti one of the highest reported uplifts in the Caribbean. The crest of the next lower reef stands at approximately 30.5 m elevation. The crest of the lowest reef (which is often the modern sea cliff) stands between 6 and 15 m. Dating of these reefs is now in progress.

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