The Structural Nature of the Laurel Creek Lineament, NC (2008)

Undergraduate: Sarah Evans

Faculty Advisor: Kevin Stewart
Department: Geology

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The relationship between topographic lineaments in western North Carolina and their associated low-magnitude seismic activity is not understood (Stewart and Dennison, 2006). This relationship may be explained by previously unrecognized fault zones corresponding to the lineaments. The 100 km long, E-W trending, Laurel Creek lineament is an ideal place to study this relationship. Prominent geologic contacts were mapped using GPS-located outcrops to determine if the contacts are offset across the lineament. About 270 m of right-lateral horizontal offset is present on the Burnsville fault, which dips about 70° to the southeast. No measurable horizontal offset was found in a vertically dipping kyanite-rich unit that crosses the lineament east of the Burnsville fault. The map pattern of the contacts can be explained by about 820 m of pure dip-slip motion. However, control on where the kyanite-rich unit crosses the lineament is poor. It is possible that there is an unresolvable right-lateral offset of this unit. If so the lineament may have 270 m of right-lateral strike-slip motion, as indicated by the offset of the Burnsville fault. Further, abundant 120° striking pinnate fractures are found along the E-W-trending lineament, which is consistent with right-lateral motion. Whether the motion is dip-slip or strike-slip, minor faulting has occurred along the lineament and therefore it corresponds to a fault zone. The present day seismicity may be a result of active slip on this fault.