Abstract:
Although one of the main advantages of palynology over other branches of micropaleontology is the extraordinary resistance of sporopollenin to chemical degradation, this highly inert substance is susceptible to oxidation. Replicate marine samples of late Pleistocene age from the New Jersey shelf were subjected to different degrees of exposure to an oxidizing agent (hydrogen peroxide). Similar palynological trends were identified with increased exposure to hydrogen peroxide, including; 1) a marked decrease in total palynomorph concentration over the first 30 minutes, 2) a marked increase in the gonyaulacacean: protoperidiniacean dinoflagellate cyst ratio which reached infinite values within the first 1/2 to 2 hours, and 3) an increase in the pollen: dinoflagellate cyst ratio over the first 1 to 3 hours. The exercise in progressive oxidation had a large impact on the dinoflagellate cyst assemblages, but a lesser impact on the pollen assemblages, presumably reflecting the selective destruction of the more susceptible taxa long before the accumulation of anemophilous terrestrial palynomorphs. The selective destruction of protoperidiniacean cysts (particularly Brigantedinium spp.) at relatively low levels of oxidation skews the sample toward the more resistant gonyaulacacean cysts (notably Bitectatodinium tepikiense and Spiniferites spp.) and resistant pollen (notably Pinus) and embryophyte spores. This taphonomic skewing should be recognized in biostratigraphic and paleoecological studies in order to avoid spurious interpretations. There are, however, positive applications of palynomorph taphonomy in sedimentological and sequence stratigraphic studies, such as in distinguishing distal turbidites from pelagites, which is difficult to accomplish using sedimentological criteria, and in distinguishing erosional surfaces from condensed sections, both of which generate strong seismic reflections.