Miospore biostratigraphy, sequence stratigraphy, and glacio-eustatic response of the Borden Delta (Osagean; Tournaisian-Visean) of Kentucky and Indiana, United States

The Borden Delta (Osagean; Tournaisian-Visean) represents a classic siliciclastic basin filling succession. Historically, the Borden Delta was thought to be deposited in response to tectonic activity centered around a peripheral bulge associated with the newly formed Acadian Highlands in the east. As the highlands eroded, the sediments were transported and deposited in the basin. This report proposes the sea level fluctuations observed in the Borden Delta rocks were formed in response to Gondwanan glaciations. Lithologic data from South America and chemostratigraphic data from numerous locations globally support this idea.; The rocks in the study area were subdivided into three Primary Depositional Centers (PDC-I, II, III) based on lithologic and stratigraphic characteristics. The rocks in PDC-I (northeastern Kentucky) were deposited during the lowstand systems tract and the transgressive systems tract of the Vanceburg Sequence. Palynologically, the rocks in PDC-I belong to the PC Biozone of Higgs et al. (1988).; The rocks in PDC-II (south-central Kentucky) represent parts of two different third order sequences (Vanceburg and Cumberland Sequences). In the eastern part of PDC-II, the Borden succession is represented by the Nancy Member only. With the continued deltaic processes, the Borden Delta migrated out of the area, leaving space for the deposition of the Cumberland Sequence during the Visean sea level rise, composed of the Fort Payne Formation (west) and the Muldraugh Member (east). Palynologically, the eastern part of PDC-II contains the PC Biozone - CM Biozone boundary. This boundary is also coeval with the Tn3b-Tn3c boundary (middle Osagean).; The Borden Delta in PDC-III is vastly different than the other parts of the study area. The Borden rocks in PDC-III are represented by parts of two third order sequences, the New Providence Sequence and the Millport Knob Sequence. Most of the sediments in this part of the Borden succession were deposited during a sea level rise in the early Visean. Palynologically, the Borden rocks in PDC-III are not correlative with the previously established biozones of western Europe. The rocks in PDC-III are part of the Scopfites claviger Assemblage, the Tumulispora sp. B Assemblage, the Tricidarisporites sp. A-Dictylotriletes sp. B Assembalge, and the Pu Biozone (western Europe).