Late Pleistocene Sedimentary History Of Continental Borderland Basins Off Baja California And Southern California Changes In Terrigenous And Biogenic Sedimentation Rates PDF Download

Analysis of cores collected from representative California Borderland basins shows that the factors influenced by climatic factors (water temperature, biological activity) show fluctuations that match those noted in deep ocean sediments. Times of cold climate and lowered sealevel also coincide with times of markedly higher sediment contribution. The peaks of this detrital contribution are sharply defined and occur at times of coldest temperature. They rapidly decline with the warming portion of the cycle. The effect of this input dilutes the more regular cycle of biological productivity to produce the apparent carbonate and carbon content of the basin cores. Thus, when the carbonate content is low, the calcium carbonate rate of sedimentation was actually faster than present but was overwhelmed by the associated pulse of terrigenous sedimentation. Similarly, the slight lag between carbon input carbonate input and sediment contribution exaggerates the difference in time of maxima in organic carbon versus carbonate carbon contents of the basin sediments. A need for a higher resolution time scale for refining the cyclicity of the sedimentation rates of individual components and the resulting combined effects is evident. (Author).