Mitchell, Simon F
Author Affiliation, Ana.
Geology of the western margin of the Benbow Inlier – implications for the relationship between the Yellow Limestone and White Limestone groups (with the description of the Litchfield Formation, new name)
Caribbean Journal of Earth Science
Date of Publication
A revised geological map for the western margin of the Benbow Inlier, Clarendon Block, Jamaica, centred on Middlesex is presented. This demonstrates that the Troy Formation (White Limestone Group) rests on an angular unconformity that progressively cuts out units in the Yellow Limestone Group (upper Yellow Limestone, Guys Hill Formation) and then cuts down into the Cretaceous succession exposed in the Benbow Inlier. This explains conflicting ages for the Yellow Limestone around Guys Hill (Early Eocene) and Yellow Limestone around the Central Inlier (middle Eocene). This also demonstrates that the units referred to as Guys Hill Formation in the Central Inlier and Guys Hill Formation in the Guys Hill area are not the same formation. The name Litchfield Formation is adopted for what has previously been called Guys Hill Formation in the Central Inlier. The Yellow Limestone and White Limestone groups of Jamaica have been interpreted to have formed during a time of tectonic quiescence, but this has to be questioned because of the presence of unconformities at the base of the Troy and Somerset formations, when active tectonism faulting, and emergence can be demonstrated. Cretaceous inliers in Jamaica (e.g., the Above Rocks and Green Bay inliers) might be interpreted as uplifted areas having lost their Yellow Limestone cover rather than as areas that were not transgressed by the Yellow Limestone sea. This work has implications for understanding the Eocene succession across the Nicaragua Rise which is currently being explored for hydrocarbons.....