Geochemical fingerprinting of sediments on the Pear Tree Bottom Reef, near Runaway Bay, Jamaica.

Pear Tree Bottom Reef, near Runaway Bay, Jamaica, was originally described by T. F. Goreau in the 1950‟s and is noted for its "Buttress Zone" morphology and presence of sclerosponges at water depths less than 30m. Since 2005, increased sedimentation has caused a drastic decline in reef health. It is thought that this increased sedimentation is related to two concurrent construction projects: the reconstruction of the north Jamaican costal highway and construction of the Gran Bahia Principe Resort along the coast adjacent to the reef. The Falmouth Limestone (~125ka), the Hopegate Limestone (~250ka), and the Montpelier Limestone (~1.9ma) all occur within the PTB River drainage basin. Reef sediment, limestone, and soils samples were analyzed for particle size, insoluble residue, mineralogy, and elemental chemistry to ascertain the source of the increased sedimentation on the PTB Reef. An ecological survey at Pear Tree Bottom indicated a drop in coral to algae ratios and therefore a decline in overall reef health. Laser particle size analysis, x-ray diffraction, ICP-MS, and ICP-ES all indicate an increase in detrital sediment on the reefs from west to the east as well as a significant increase at Pear Tree Bottom that is likely a result of the resort construction.