Reevaluation of the southwestern end of the Salem synclinorium

Observed stratigraphic variations within the Salem synclinorium in the Valley and Ridge Province of the southern Appalachians are part of a larger basinal setting. The basal conglomerate of the Ordovician Bays Formation is restricted to the limb of the synclinorium reflecting a regional trend of coarser sedimentation nearest the Taconic sediment source. Ordovician/Silurian and Silurian/Devonian unconformities have removed more section from the southern portion of the synclinorium which has been interpreted as evidence of a more landward setting for this area. Previous interpretations of these coarser sediments and unconformities theorized the synclinorium was a unique depositional basin active throughout Paleozoic time. The relationship between veins, fractures, slickensides, oblique-slip faults and thrusts in a riverbed exposure within the southwestern portion of the Salem synclinorium, offers a structural model for the Salem synclinorium. Thrusting induced extensional fractures and veins. Oblique-slip faults which cut the thrusts may have nucleated on these preexisting extensional features. On a larger scale, extensive secondary fracturing between faults may have produced the larger fault zones observed in the synclinorium. Although stratigraphic thickness variations within the synclinorium correspond to observed fold wavelength variations, faulting disrupts many of these folds and distorts the wavelength estimate. Faulting, not folding, is the dominant structural process. Ramp size and horse blocks are theorized to control fold wavelength within the Salem synclinorium.

Name thesis:degree_name

M.S.

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Geological Sciences

Department dc:contributor.department

Geological Sciences

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1986

Author dc:creator

• McHugh, Mary Lopina

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10919/101123

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/101123