Age Assignment of the Erin Slate, Talladega Slate Belt, Clay County, Alabama

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A controversy exists surrounding the age assignment of the Erin Slate, outcropping in the Talladega Slate Belt of Alabama. The age assignment of this unit has become pivotal in the paleotectonic interpretation and timing of emplacement of the Talladega slate belt in the southern Appalachian orogen. The disputed age assignment of the Erin Slate is based on the reported presence of permineralized Carboniferous lycophyte cones, Lepidostrobus hobbsii D. White. Subsequent workers were unable to collect additional permineralized fossil plants, although compression-impressions have been documented in the matrix and an indistinguishable petrologic similarity between the Erin Slate and matrix adhering to one of the cones exists. The lack of subsequently collected material, equal in preservational mode and type to that of the original two lycophyte cones, has led some workers to question the validity of a fossiliferous Erin. The original plant fossils are currently considered to be "exotics", and the Erin Slate has been lithostratigraphically correlated with the Early Devonian Jemison Chert. Newly discovered permineralized plant fossils provide unequivocal evidence that the Erin slate is fossiliferous. The project herein proposed is designed to assess this newly recovered paleobotanical evidence for a definitive age assignment of the Erin Slate and its regional correlatives. The taxonomic diversity and systematic affinities of this permineralized flora will be ascertained and compared with those plants of homologous structural advancement, paleogeographic distribution, and biostratigraphic position. The age assignment based on the constraints of the paleobotanical evidence will form the foundation for evaluating the tectonic setting of the Erin Slate and its relationship to the tectonic framework now proposed for the southern Appalachians.//