IDENTIFICATION OF PALEOZOIC PARASEQUENCE SETS IN MISSISSIPPIAN-AGED BASINAL CLASTICS OF THE EASTERN NORTH AMERICAN MIDCONTINENT, USA

Sequence stratigraphy has been an extremely useful tool for interbasinal correlations and eustatic relations for nearly a half century. In that time, high-resolution sequence stratigraphy has become more useful in post-Paleozoic rocks rather than older Paleozoic strata.

This report centers on Tournaisian-aged strata from Paleozoic basins in Kentucky and Michigan. In Kentucky, the Farmers Member of the Borden Formation (Mississippian; Tournaisian) represents a basin floor fan complex deposited as a result of the Osagean forced regression, which occurred at the Kinderhookian-Osagean boundary. Using spores, the Farmers Member has been identified as the PC Biozone, which makes it part of the late Tournaisian (Osagean). The Farmers Member was deposited during the lowstand systems tract of Vanceburg Sequence (3^rd order sequence). Analysis of outcrops of the Farmers Member has revealed the presence of prograding parasequence sets. To the north in the Michigan Basin, the Marshall Sandstone (Mississippian; late Tournaisian) was also deposited as a result of the Osagean forced regression. The Marshall Sandstone has been dated as the PC Biozone and is believed to have been deposited during the lowstand systems tract of Osagean Sequence 1. Analysis of geophysical logs from the Marshall Sandstone has revealed prograding parasequence sets. Future analysis may also reveal parasequence sets in age-equivalent strata in Ohio and West Virginia.

Although the identification of parasequence sets is difficult in Paleozoic strata, the results of this report will help interbasinal correlation of Paleozoic rocks in the midcontinent and aid in the complexes relations concerning deposition environments.