Wooster Geologists in Jamaica May 2001 (Page 2)

Richie Richie's "Resort" west of Rio Bueno was the best place to study the upper part of the Falmouth Formation. The exposures here are extensive, with one fairly dry portion where fossils and rhodoliths (circumrotatory balls of calcareous red algae and other skeletal organisms) can be easily collected. The base of the Falmouth here is below mean sea level, so it cannot be easily observed.

The Falmouth Formation exposed at Richie Richie's Resort on the west headland of Rio Bueno Harbour. Note in the center the three Wooster students standing by a fresh exposure. A larger version of this image is available.

A closer view of the Falmouth at Richie Richie's. Above the Diploria coral head is a lens cap for scale. The white round objects are rhodoliths. A larger image is available.

The rhodoliths and extensive coral debris indicate fairly high energy deposition. This portion of the Falmouth may have been formed along a reef crest or in the upper part of the fore reef zone. Some geologists have suggested that the layers of broken corals represent "hurricane horizons".

Near the top of the Falmouth at Richie Richie's is an extensive surface easily detected by thick terra rosa mantling. Corals are truncated along this surface, and then it is later covered by additional Falmouth deposition. It is possible that this surface represents a eustatic sea level drop and rise similar to that described by Wilson and others in contemporary rocks of the Bahamas (Lethaia 31: 241-250; 1998). Oddly, though, there are no borings visible in the Falmouth surface, and yet they are extremely abundant in the Bahamian surfaces.

The possible erosional surface within the upper part of the Falmouth Formation at Richie Richie's. The surface is marked by heavy terra rosa deposits and truncated corals, and then it is succeeded by more Falmouth sediment and corals. Borings were not seen on the surface, however. A larger version of this image is available.

An extensive exposure of the upper Falmouth surface showing the heavy terra rosa. In the background is the stratigraphic continuation of the Falmouth. A larger image is available.

In some places the surface is well exposed as a bedding plane, with remnants of the upper Falmouth adhering in parts. The terra rosa is sometimes several centimeters thick and even conglomeratic. Still, though, even in these large exposures no bivalve, sponge or polychaete borings are evident. Were they present and later eroded away?

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