RESOURCES FOR AN EXPANDING AND INQUISITIVE COMMONWEALTH: NEW GEOLOGIC MAPS ARE KEYS FOR NATURAL RESOURCE ASSESSMENT ALONG I-81 AND PROPOSED I-73 CORRIDOR BETWEEN ROANOKE AND CHRISTIANSBURG, VIRGINIA

Digital geologic maps and cross sections of the Bent Mountain and Elliston 7.5-minute quadrangles prepared for the VT- DMME STATEMAP cooperative mapping project highlight complex Appalachian thrust structures as well as Neoproterozoic thru Mesozoic basin and range geology at the join between the Central and Southern Valley and Ridge. The mapped area includes the proposed I-73 corridor at the NE terminus of the Blue Ridge Plateau as well as a proposed new multilane I-81 project that crosses a newly recognized seismic zone at the SW end of the Roanoke Valley Metro area. A major intermodal freight facility is also being proposed in gravel-covered karst lands SE of the Pedlar Hills Preserve (VDNR) along the Roanoke Valley overthrust near Elliston.

Potential Mineral Resources include aggregate (granite, gneiss, limestone and quartzite), agricultural limestone and dolomite, shale/brick clay deposits, glass sand, lead-zinc and iron ore and unconventional gas from Ordovician and Devonian black shales. Major surface and groundwater resources, both free flowing and impounded have been developed within the thrust-faulted Blue Ridge-Valley and Ridge boundary zone. Major science education resources are also present and accessible in the area owing to intense uplift and erosion of the imbricate thrust zone along the western Blue Ridge escarpment. From the Bottom Creek (Nature Conservancy) Preserve, where deeply eroded 500 foot cliffs of Mesoproterozoic granitic rocks are exposed to the fossil shell beds in the Devonian Foreknobs Fm. on the upper slopes of Fort Lewis Mountain there are at least 650,000,000 years of earth history to be studied. There is also a nearly intact Neoproterozoic rift basin on Poor Mountain. The Unicoi Fm. contains coarse sedimentary breccia beds along the “Great Unconformity” overlain by felsic then mafic metavolcanics which are succeeded by a basin fill sequence that grades into graphitic phyllite to the southwest in Floyd County.