Upper Quaternary peat deposits on the Atlantic inner shelf of the United States

Abstract

Twenty-one upper Quaternary peat samples have been obtained from vibracores collected along the inner continental shelf of the Atlantic coast of the United States. Radiocarbon ages and pollen identifications from the peats, coupled with those from onshore borings and published data, provide additional information on the latest history of the Atlantic shelf. The radiocarbon ages cluster in two groups: early and middle Holocene time (10,000 to 5,000 B.P.) and late Pleistocene time (35,000 to 20,000 B.P.). Although ages and depths of the upper Pleistocene peats show some agreement with published graphs of changes in sea level, pollen data indicate that most of the peats formed in terrestrial environments and therefore may be unreliable as indicators of sea level. The Holocene peats were deposited in both marine and terrestrial environments. Correlation of the stratigraphic sequences in the cores containing peat with high-resolution seismic reflection profiles indicates a history of transgressive erosion on the inner shelf. Only remnants of carbonaceous sediments originally deposited in bogs, ponds, estuaries, and salt-marsh lagoons are present in the shallow subsurface on the inner shelf. These remnants, which are discontinuous and usually associated with erosional unconformities, provide evidence of regional marine planation of the shelf by the rising Holocene sea.