THIN SECTION ANALYSIS OF THE LOWER CAMBRIAN ROME FORMATION IN ALABAMA AND GEORGIA: INVESTIGATING SEDIMENT SOURCE TERRANES DURING RODINIA RIFT-TO-DRIFT EVOLUTION

In the southern Appalachian foreland thrust belt of Alabama and Georgia, the Lower Cambrian Rome Formation consists of moderate-red to grayish-green shale, yellow to moderate-brown siltstone and sandstone, and locally beds of limestone and dolomite. Anhydrite beds are present in subsurface cores. Exposures are maroon, purple, and light-green silty mudstone and argillaceous sandstone, which are generally thin (5-20 cm), but thicker beds (1-2 m) are present. In outcrop, sandstone beds range in composition from ~ 65-10-25 QFL to ~ 85-10-5 QFL, contain silt- to medium-grained, well-sorted clasts, are rounded to subrounded, and commonly contain symmetric ripples at bedding planes.

Clastic facies in the Rome Formation are hypothesized to exhibit a continental-wide Laurentian provenance. However, a paucity of data limits the ability to distinguish between central craton and syn-rift sediment source terranes. We present thin section petrology analyses from the Rome Formation to better characterize sediment source terranes. Results from this study advance our understanding of upper-crustal characteristics and surface processes along the southern margin of Laurentia during Rodinia rift-to-drift evolution.