GEOLOGY OF THE UNAKA MOUNTAIN-LIMESTONE COVE FAULT AND A PART OF THE LIMESTONE COVE WINDOW, NORTH CAROLINA-TENNESSEE

The Limestone Cove Window (LCW), located approximately 21 km south of Johnson City, Tennessee, on the North Carolina - Tennessee border, is a subwindow of the Mountain City Window. It is bounded by three faults: the Limestone Cove Fault (LCF) in the northeast, Unaka Mountain Fault (UMF) in the southeast and the Norris Branch Fault in the southwest. The LCW and Unaka Mountain Fault have been mapped in several different ways and UMF has been described as a brittle thrust fault cut by three strike-slip faults. Detailed geologic mapping and petrographic observations indicate the following: (1) the UMF-LCF, bounding the LCW on the SE and NW, is a folded thrust with NW and SE dips; (2) rocks within the LCW are folded into an anticline - syncline pair that plunges gently to the NE; (3) field and petrographic observations indicate that the Unaka Mountain - Limestone Cove Fault and other associated thrust faults are ductile; (4) mineral elongation lineations and sense of shear indicators suggest NW transport on the UMF-LCF; (5) two additional ductile thrust faults occur within the area that are part of the LCW duplex; (6) in the vicinity of Davis Springs, a high angle normal fault juxtaposes the upper member of the Erwin Formation and the Shady dolomite; and (7) no strike-slip faults are present in the part of the LCW mapped in this study. We thank the USGS EDMAP Program, the states of Tennessee and North Carolina, Appalachian State University, and the University of Tennessee for support.