The Geology of Jamaica
There was only a single young volcanic eruption on the island of Jamaica. This produced the Low Layton Lava, which forms a prominent east-west ridge on the north shore of the island. It was a shallow water alkali olivine basalt eruption that produced pillow lavas, hyaloclastite, lava flows and dikes. The pillow lavas represent submarine activity and the hyaloclastite a shallow-water emergent facies. A K-Ar age for the eruption yields a Miocene date of 9.5 +_ 0.5 Ma. The ridge of basaltic material appears to have been erupted from a series of ENE en-echelon fissures. The ridge parallels the northern coastline of Jamaica, as well as the Cayman Trough to the north. It is believed to overlie the Dunavale Fault Zone which is a major Cenozoic strike slip structure related to the formation of the Cayman Trough.