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Thrust fault zones in the Allegheny Plateau of north-central Pennsylvania

Open-File Report 79-1604

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Abstract

Field investigations in the Williamsport Valley identify lineaments found on Landsat III images, have shown the presence of six discrete fault zones that strike subparallel to the trend of the Appalachian folds. These zones range from 0.5 to 1.75 km in width and from at least 10 km to more than 50 km in length. The individual thrust faults within each zone occur in 'staircase-type' folds and are at a low angle to bedding. Although each individual fault may have 0nly centimeters to displacement, many of these individual faults appear to exist within the six zones. We believe that the stress that produced that Valley and Ridge folds to the south was largely dissipated in faulting in the Williamsport Valley. This dissipation of the stress would explain the presence of only broad open folds to the north on the Allegheny Plateau. The extreme faulting in the Williamsport Valley along with the unique 'staircase' and 'reverse staircase' structures may result in fracture porosity traps at depth.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Thrust fault zones in the Allegheny Plateau of north-central Pennsylvania
Series title:
Open-File Report
Series number:
79-1604
Edition:
-
Year Published:
1979
Language:
ENGLISH
Publisher:
U.S. Geological Survey,
Description:
16 p. :ill., maps ;28 cm.