Relict Sediments on Continental Shelves of World

ABSTRACT The sediments that were deposited on the continental shelves during and immediately after the latest glacial stage of the Pleistocene Epoch are unrelated to their present environments. The rise of sea level during the past 19,000 yrs has caused previously deposited subaerial, lacustrine, and paludal sediments to become submerged in shallow-marine waters, and later to become deeply submerged. Land-laid or shallow-marine sediments which occur in deep water, such as those near the seaward edge of the continental shelf, are properly termed “relict.” At present, the sediments exposed atop about 70 percent of the area of the continental shelves of the world can be identified as relict. Eventually, new detrital sediments that are contributed to the ocean by streams or shore erosion should prograde entirely across the continental shelf and bury the relict sediments. This burial should be hastened if the rise of sea level remains as slow as it has been during the past few thousand years; nevertheless, several tens of thousands of years probably will be required before most of the relict sediment becomes buried.