The Pleistocene rocks of Bermuda consist of shallow-water, beach, and intertidal marine biocalcarenites; eolianites; and red soils, displaying complex facies relationships. Eolianites grade laterally into marine biocalcarenites, indicating deposition during times of high sea level, or interglacial episodes. During glacial times, red soils formed over the present area of Bermuda. Because no evidence for Pleistocene tectonism has been discerned, the Bermuda Islands may represent a good “tide gauge” for the assessment of Pleistocene eustasy.
The determination of Bermudian stratigraphy requires recognition of environments of deposition and interpretation of the subsequent diagenetic history of the various units. Bermudian marine biocalcarenites can be distinguished from eolianites. The two red soils represent solutional unconformities, during which time fresh-water percolation induced diagenesis in the underlying rocks. Bermudian calcarenites can be divided into five diagenetic grades, representing increasing intensity of fresh-water alteration. Fossil land snails provide some criteria for the recognition of units.
Radiochemical dates are available for most formations and allow a quantitative assessment of Pleistocene eustasy for the last 200,000 years. Bermudian stratigraphy records sea-level fluctuations and can only be interpreted rationally as the result of Pleistocene eustasy.