Masters Theses
Date of Award
6-1986
Degree Type
Thesis
Degree Name
Master of Science
Major
Geology
Major Professor
Nicholas B. Woodward
Committee Members
Kenneth Walker, Don Byerly
Abstract
The Buffalo Mountain thrust sheet, located along the western margin of the Blue Ridge structural province in northeastern Tennessee, provides an excellent opportunity to examine transitional structural styles and deformational mechanisms between the Valley and Ridge and Blue Ridge.
The Buffalo Mountain sheet is composed of a sequence of Lower Cambrian Chilhowee Group elastics that have been thrust over Upper Cambrian Conasauga Group shales and Cambre- Ordovician Knox Group carbonates. The entire stack has been imbricated into four interleaved thrust slices and is folded into a northeast trending doubly plunging syncline.
Field mapping and indirect examination of thrust plane orientations reveal that all thrust faults in the area place older rocks over younger rocks, cut up stratigraphic section through both foot wall and hanging wall strata, and do not cross-cut or displace each other. These data suggest that the Buffalo Mountain area has experienced only one episode of contractional thrust faulting.
The structural relationships at Canah Hollow, along the southwestern corner of the Buffalo Mountain sheet, are interpreted as a foreland-dipping duplex. The duplex is composed of horses torn away from both the foot wall Holston Mountain sheet and the hanging wall Buffalo Mountain sheet. The structural history of Canah Hollow provides an example of progressive deformation during a single episode of in-sequence thrusting.
The small klippe of Unicoi within Canah Hollow was originally part of the Pinnacle sheet, and has been repositioned by either minor faulting, erosional collapse, or mass wasting.
Small scale structures within the hanging wall rocks of the Buffalo Mountain thrust sheet include quartz-filled fractures, fractured grains, pressure solution traces, undulatory extinction, and just above the Buffalo Mountain thrust surface, ribboned quartz grains, and crenulation cleavage. The small scale structures associated with the foot wall rocks of the Buffalo Mountain sheet are characterized by a cataclastic fabric (crushed, cracked, and fractured grains) that lacks an internal foliation, styolitic pressure solution traces, and mineral-filled conjugate en echelon fractures.
The large scale geometric relationships between major thrust sheets combined with the orientation of minor structures suggests that thrust sheet emplacement in the northeast Tennessee Blue Ridge has occurred in a hinterland to foreland fashion. Specifically, the folding of the Buffalo Mountain thrust sheet is probably due to the vise effect caused by the emplacement of the structurally lower, more foreland Limestone Cove duplex and Pulaski sheet.
The absence of a strain contrast across the Buffalo Mountain sheet combined with the laterally overlapping geometry of the imbricate sheets suggest that the imbricate sheets formed simultaneously during folding.
Thus, the Buffalo Mountain area provides a group of structurally complex features that have formed during a single progressive episode of hinterland to foreland thrusting.
Recommended Citation
Duddy, Mark Morgan, "Characteristics of Thrust Fault Imbrication Along the Western Margin of the Blue Ridge Structural Province Buffalo Mountain, Tennessee. " Master's Thesis, University of Tennessee, 1986.
https://trace.tennessee.edu/utk_gradthes/4624