Abstract

A sequence of Pliocene-Pleistocene carbonate rocks preserved on the western side of the island of Bonaire, Netherlands Antilles, represents a thick build-up of sediment deposited mainly on the flanks of the Cretaceous volcanic core of the island. This sediment built up and developed a shallow-water shelf similar to the one that surrounds the island today. Sediments at the top of the section and the updip portions of beds lower in the section have been dolomitized in two episodes of dolomitization. Minor sea-level fluctuations occurred during deposition of this sequence, and a major lowering of sea level terminated sedimentation.

Carbonate rocks and terraces were superimposed on Pliocene-Pleistocene rocks as the island was subjected to uplift and (or) sea-level fluctuation during Pleistocene time. Seven well-developed terraces are present and range from 5 to 90 m above present sea level. Two distinct episodes of terrace formation are represented. The two highest terraces at 90 and 70 m were formed during the earlier episode. Relative sea level was lowered at least 60 m, exposing Pliocene-Pleistocene dolomite and limestone to subaerial erosion. A rise in sea level to approximately 50 m was accompanied by deposition of carbonate sediment on the erosion surface. Marine sediment filtered down into fractures and solution cavities in the underlying rock. This cavity-filling sediment and the lowermost limestone deposited on the erosion surface have been dolomitized. Subsequent uplift of the island and (or) eustatic lowering of sea level were accompanied by extensive deposition of eolianite at elevations above 50 m. Terraces of erosional and depositional origin were formed during this regression at elevations of 50, 30, 20, 10, and 5 m. Deposition of sediments associated with the present 5-m terrace occurred during a high stand following a major lowering of sea level.

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