MISS, POSSIBLE MISS, AND OTHER MICROBIAL STRUCTURES FROM THE LOWER CAMBRIAN ROME FORMATION OF EASTERN TENNESSEE AND SOUTHWESTERN VIRGINIA

Several examples of microbially induced sedimentary structures (MISS) and possible MISS have been recognized from the Lower Cambrian Rome Formation during preliminary fieldwork in Southwestern Virginia and Eastern Tennessee. Although MISS are common features of Lower Cambrian intertidal and subtidal facies, and the trace fossil and (limited) body fossil faunas from the Rome have been well studied, MISS have not been systematically documented from the Rome. A combination of analysis of field relationships and hand samples, examination in SEM, and analysis of petrographic thin-sections is used to evaluate MISS and potential MISS for evidence of biogenicity. Structures resembling domal sand buildups and algal balls have been identified. Oncolites have also been recognized from uncommon limestone layers. Other observed structures are more ambiguous and may be of either microbial or abiotic early diagenetic origin.