Palynological Characteristics of Near-Shore Shell-Bearing Pliocene Through Holocene Sediments of Florida, Georgia, and South Carolina

Frederick J Rich

Abstract


Seventeen pollen-bearing samples· from sites in South Carolina, Georgia, and Florida were analyzed for their pollen content. The samples range in age from Late Pliocene to Holocene. The initial objective of the study was to use the samples to help define the age of the physiographic feature known as Trail Ridge. All samples were marine sediments, and many were from marine mollusk-dominated strata. Pollen of Pinus and Quercus were abundant in all samples; Taxodium was abundant in about half of them. Carya, Liquidambar, Compositae, Gramineae, and ChenopodiaceaeAmaranthaceae were present as accessory taxa. Dinoflagellate cysts, microforams, and pyrite were present, or abundant, in several of the samples. The only regionally extinct taxa were Pterocarya and Sciadopitys (?), and these were not abundant in any samples. The bio- and chronostratigraphic positions of the samples were established using mollusk, ostracode, and vertebrate fossil data, and radiocarbon dates where possible. In spite of the fact that the samples represent a considerable span of time (back to 2.2 million years) the pollen floras are very uniform. There is, for all practical purposes, no way of distinguishing the sampled Pliocene strata from the Pleistocene or Holocene units on the basis of pollen assemblages. The pollen floras seem to have been strongly influenced by taphonomic factors, such as sorting by wind, currents, and waves. Although this has nearly eliminated their value as biostratigraphic indicators, the pollen assemblages are useful indicators of a distinct kind of depositional setting. The taphonomic interpretation is corroborated by data derived from molluscan and vertebrate paleoecology.


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