An area of 45 square miles was sampled south of St. George Island in the Gulf of Mexico with a total of 38 samples being obtained. This area has an undulatins bottom due to a series of ridges and troughs trending approximately east and west across it. Differences were found in the terrigenous sediments taken from the ridges when compared with those obtained from the troughs on either side of them. These sediments on the ridges had a smaller median grain size and better sorting than the material in the adjacent troughs or lows. The CaCO3 percentage was also lower in those locations. However, the terrigenous sediment on the ridges was not found to be statistically different from that found in the troughs for the area as a whole. Fourteen varieties of heavy minerals were identified in the area. The suite present is indicative of a high rank metamorphic source area. Two authigenic varieties were found. The data from the present area were compared statistically using the median test with the previously examined eastern area of Dog Island. This eastern area has an even profile typical of off-bar areas. The median grain size or the terrigenous sediments was found to be significantly different at the 5 percent level between the two areas with the eastern area having coarser material. Obvious differences between the two areas are the presence of heavy minerals in measureable amounts in the area off St. George Island as opposed to only a trace off Dog Island; and the presence of bed rock in the eastern area whereas none was found in the western area.

No Abstract Avaliable

Ocean Drilling Project (ODP) Hole 625B from 890 m water on the West Florida carbonate ramp-slope provides a continuous 235 m long record of cyclic sedimentation responding to global climatic change and regional tectonics over the past 5.4 Ma. Relatively rapid sedimentation rates (> 5 cm/1000 yr) and a 30 cm sampling interval (6-10,000 yr) permit a high-resolution investigation of Milankovitch-influenced carbonate sedimentation on a continental margin. Total carbonate, percent coarse (> 63 mu m), and oxygen isotope data exhibit good correlation with established mid- and late-Pleistocene composite records, indicating that the climate signal recorded on the West Florida slope closely parallels the global climate signal obtained from deep-sea sediments.