TY - JOUR
T1 - Surface morphology on cross-fold joints of the Appalachian Plateau, New york and Pennsylvania
AU - Bahat, Dov
AU - Engelder, Terry
N1 - Funding Information:
This work was supported by ARC0 Oil and Gas Company Division of Atlantic Richfield Company. We have profited from discussions with scientists within this company, especially James Helwig. Howard Pohn has kindly provided us with information on several outcrops. The Nuclear Regulatory Commission contract NRC-04-81-180 and NSF Grant EAR-83-06146 also supported this work. Various versions of this paper were reviewed by Steve Brown, Tracy Johnson, Russ Wheeler, and Byron Kulander. The helpful comments by the editor are also acknowledged. Lamont-Doherty Geological Observatory contribution number 3542.
PY - 1984/5/1
Y1 - 1984/5/1
N2 - On the Appalachian Plateau of New York and Pennsylvania plume patterns are present on surfaces of all cross-fold joints that cut siltstones, but they are not common on either cross-fold joints or strike joints cutting shales. Near Watkins Glen, New York, joints cutting siltstones display two types of plumose patterns; each particular type correlates with a specific cross-fold joint set. The more easterly striking cross-fold joints (345° i.e., N15°W), cutting thin siltstone beds embedded in thicker shale formations, have straight plume patterns with axes parallel to bedding. More westerly striking cross-fold joints (335°), cutting thick siltstone beds, have curved plume patterns with axes that either curve or show fan-like rhythmic patterns that alternately increase and decrease in intensity. Joints cutting only shales exhibit no distinct surface morphology other than long arcuate arrest lines. The fan-like rhythmic patterns of plumes suggest that these joints formed by a cyclic process (perhaps related to pore pressure variations) rather than by one massive rupture.
AB - On the Appalachian Plateau of New York and Pennsylvania plume patterns are present on surfaces of all cross-fold joints that cut siltstones, but they are not common on either cross-fold joints or strike joints cutting shales. Near Watkins Glen, New York, joints cutting siltstones display two types of plumose patterns; each particular type correlates with a specific cross-fold joint set. The more easterly striking cross-fold joints (345° i.e., N15°W), cutting thin siltstone beds embedded in thicker shale formations, have straight plume patterns with axes parallel to bedding. More westerly striking cross-fold joints (335°), cutting thick siltstone beds, have curved plume patterns with axes that either curve or show fan-like rhythmic patterns that alternately increase and decrease in intensity. Joints cutting only shales exhibit no distinct surface morphology other than long arcuate arrest lines. The fan-like rhythmic patterns of plumes suggest that these joints formed by a cyclic process (perhaps related to pore pressure variations) rather than by one massive rupture.
UR - http://www.scopus.com/inward/record.url?scp=0021619405&partnerID=8YFLogxK
U2 - 10.1016/0040-1951(84)90128-8
DO - 10.1016/0040-1951(84)90128-8
M3 - Article
AN - SCOPUS:0021619405
SN - 0040-1951
VL - 104
SP - 299
EP - 313
JO - Tectonophysics
JF - Tectonophysics
IS - 3-4
ER -