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Abstract: Modeling Paleobathymetric and Relative Sea Level Curves from Palynofacies Analysis and Palynomorphs Paleoecology

Carlos Jaramillo, Oscar Yepes, Franca Oboh

Palynofacies and lithofacies from seven stratigraphic sections from the Cretaceous and Quaternary of Colombia, and the Paleogene of the U.S. Gulf Coast, were used to reconstruct paleobathymetric and relative sea level curves for these stratigraphic intervals. These curves were compared with those produced by other techniques.

Our palynological methodology consists of two major components: a palynofacies analysis and a paleoecological Interpretation of palynomorph assemblages. The palynofacies analysis includes three main steps: first, 300 organic matter particles are counted in each sample, recording composition, size, sorting and degradation. The second step involves the statistical treatment of the recorded data. Under the assumption of a dominance of allocyclic processes, the clustered samples are ordered according to their organic matter content, which indicate their positions relative to the paleoshoreline. The last step consists of constructing the relative paleobathymetric curve based on the composition and relative change of the palynofacies groups along the studied stratigraphic section.

The second major component involves the paleoecological analysis of dinoflagellates, pollen and spores. Taxa are clustered according to several statistical treatments and the paleoecological significance of each group is interpreted based on the current literature. When correlating several sections, clusters from every section are compared to obtain strong paleoecological associations that mainly reflect a position relative to the shoreline. This proposed technique is useful either in continental rocks or in marine rocks, increasing the potential for successful basin-wide correlation. Furthermore, it can be used in sediments as old as Carboniferous.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela