DENSELY-PACKED HORIZONS OF ASTEROSOMA TRACES IN THE PENNSLYVANIAN-AGE BLOYD FORMATION

A set of trace-rich horizons exist stratigraphically below the middle Bloyd sandstone unit at the edge of the Arkansas River Valley and Boston Mountains area of Arkansas. The Pennsylvanian-age paleoenvironmental setting saved in strata, at a popular hidden waterfall exposure in Ozark National Forest, possess densely packed Asterosoma. A detailed stratigraphic column of this primary exposure was drafted to link these trace-rich horizons to other exposures in the area that are known to bear similar traces. The attitude and differential weathering of the strata at this primary site allows for large indurated blocks of sandstone bearing Asterosoma to fall at the base of a long wall of bedding contacts (horizons), also bearing the traces. Ichnotaxonomic, morphological, and in situ spatial data were collected from field observations, photographs, and analyses using photo editing software. A new measurement method for calculating density "linear density" using trace information exposed along the horizons was also deployed. Results from the multiple perspectives indicate the dense packing of tracemakers at this location, indicating nutrient-rich shallow sea environment. Future work in the correlatable nearby exposures will map the extent of this particularly unique paleoenvironmental setting in the expansive Bloyd formation.