Geometry and structural development of the Saltville thrust system, southwestern Virginia

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:6112935

Bartholomew, M J ^[1]; Lewis, S E ^[2]; Schultz, A P; McDowell, R C ^[3]

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1. Univ. of South Carolina, Columbia, SC (United States). Earth Sciences and Resources Inst.
2. Westinghouse Savannah River Co., Aiken, SC (United States)
3. Geological Survey, Reston, VA (United States)

The structural components of the Saltville thrust system are: (1) the main Saltville thrust is at the base of the Mississippian-Cambrian sequence; this thrust tips in the Sinking Creek anticline; (2) the Maggie thrust displaces the overturned limb of the anticline forelandward of the overturned limb of the Clover Hollow Mountain (footwall) syncline; (3) the en echelon series of footwall synclines extends 25 km SW from the Maggie thrust to Poplar Hill; (4) the Brushy Mountain (hinge) fault extends from Poplar Hill > 20 km SW beyond Mechanicsburg; and (5) smaller faults are associated both with detachment of some footwall synclines from the subjacent Narrows thrust sheet and with destruction of overturned limbs of the footwall synclines. This northern 100 km-long, terminal segment of the Saltville thrust most resembles recent models of fault propagation folding. A high initial ramp-angle (20--30[degree]) favored development of a footwall syncline. A more stable, low ramp-angle (10--15[degree]) was subsequently achieved through ramp-smoothing processes related to destruction of the footwall syncline through flattening (cleavage development), faulting through the hinge, and detachment of the syncline from the footwall. As displacement decreases northeastward along the Saltville thrust, some displacement is absorbed in the ramp-smoothing, syncline-destruction processes and some is transferred to the Maggie (breakthrough) thrust. After breakthrough the syncline-destruction processes produced hinge-migration and rotation resulting in cleavage-transected folds in proximity of the footwall syncline. The fault zone that detaches the footwall syncline is folded about the younger Clover Hollow anticline. Cleavage is axial planar to the Clover Hollow anticline indicating that cleavage development in the footwall accompanied all developmental stages of the Saltville thrust system and continued through initial development of a structurally lower duplex.

• OSTI ID: 6112935
• Report Number(s): CONF-9304188--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:4
• Country of Publication: United States
• Language: English

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