Mitchell, Simon F.; Pickerill, Ron K.; Blackwell, Bonnie A.; Skinner, Anne R.
Author Affiliation, Ana.
Department of Geography and Geology
The age of the Port Morant formation, south-eastern Jamaica
Caribbean Journal of Earth Science
Date of Publication
Two coral samples from the Port Morant Formation in south-eastern Jamaica have been dated using electron spin resonance (ESR). Petrographic analysis showed some dissolution of the primary coralline aragonite as well as secondary mineral precipitation within the coral pore space in the one sample, which also showed large associated uncertainties for accumulated doses calculated from the ERS growth curves. therefore, the age, 125 ± 7 kyr, for the sample probably represents a minimun age, being a weighted average of the date of the original skeletal aragonite and that for the secondary mineral phase. The second specimen yielded a single age of 132 ± 7 kyr. Although we regard this as an accurate age, no single date can be considered to be totally reliable by itself. The ages suggest that at least part of the Port Morant Formation was deposited during the latest Isotope Stage 6 and probably earliest Stage 5e. More dates fromt he unit, however, are necessary to confirm this conclusion.....