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Title: Low-angle extensional faulting, reactivated mylonites, and seismic reflection geometry of the Newark basin margin in eastern Pennsylvania

Abstract

Low-angle 25/sup 0/ to 35/sup 0/ dips have been determined for the border fault of the Newark basin near Riegelsville, Pennsylvania, on the basis of a Vibroseis profile and two continuously cored drill holes across faults at the basin margin. A group of moderately strong planar reflections in a zone 0.5 km thick in gneiss and carbonate rocks of the footwall block coincides with the updip projection of imbricate fault slices and mylonites associated with the Musconetcong thrust system of Drake et al. (1967). Contrasts in acoustic impedance among mylonitic dolostone and mylonitic gneiss and their protoliths, determined from measurements on samples from a third cored hole, are sufficiently large to account for reflections seen in the footwall block. Analysis of drill core and surface outcrops supports the conclusion that low-angle extensional faulting in the early Mesozoic was localized by reactivation of Paleozoic imbricate thrust faults in the basement rocks. Extension in the northwest-southeast quadrant was approximately perpendicular to the strike of the ancient thrust faults in eastern Pennsylvania. The data presented here are the most explicit three-dimensional information obtained thus far in the eastern US in support of the concept of fault reactivation in controlling formation of early Mesozoicmore » extensional basins.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Geological Survey, Reston, VA
OSTI Identifier:
5717848
Resource Type:
Journal Article
Journal Name:
Geology; (United States)
Additional Journal Information:
Journal Volume: 14:9
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; GEOLOGIC DEPOSITS; GEOLOGIC FAULTS; SEISMIC SURVEYS; TECTONICS; PENNSYLVANIA; BASEMENT ROCK; BOREHOLES; CARBONATE ROCKS; DATA ANALYSIS; DRILL CORES; GEOLOGIC HISTORY; GEOMETRY; GNEISSES; MESOZOIC ERA; PALEOZOIC ERA; CAVITIES; FEDERAL REGION III; GEOLOGIC AGES; GEOLOGIC FRACTURES; GEOLOGIC STRUCTURES; GEOPHYSICAL SURVEYS; MATHEMATICS; METAMORPHIC ROCKS; NORTH AMERICA; ROCKS; SEDIMENTARY ROCKS; SURVEYS; USA; 580201* - Geophysics- Seismology & Tectonics- (1980-1989)

Citation Formats

Ratcliffe, N M, Burton, W C, D'Angelo, R M, and Costain, J K. Low-angle extensional faulting, reactivated mylonites, and seismic reflection geometry of the Newark basin margin in eastern Pennsylvania. United States: N. p., 1986. Web. doi:10.1130/0091-7613(1986)14<766:LEFRMA>2.0.CO;2.
Ratcliffe, N M, Burton, W C, D'Angelo, R M, & Costain, J K. Low-angle extensional faulting, reactivated mylonites, and seismic reflection geometry of the Newark basin margin in eastern Pennsylvania. United States. https://doi.org/10.1130/0091-7613(1986)14<766:LEFRMA>2.0.CO;2
Ratcliffe, N M, Burton, W C, D'Angelo, R M, and Costain, J K. 1986. "Low-angle extensional faulting, reactivated mylonites, and seismic reflection geometry of the Newark basin margin in eastern Pennsylvania". United States. https://doi.org/10.1130/0091-7613(1986)14<766:LEFRMA>2.0.CO;2.
@article{osti_5717848,
title = {Low-angle extensional faulting, reactivated mylonites, and seismic reflection geometry of the Newark basin margin in eastern Pennsylvania},
author = {Ratcliffe, N M and Burton, W C and D'Angelo, R M and Costain, J K},
abstractNote = {Low-angle 25/sup 0/ to 35/sup 0/ dips have been determined for the border fault of the Newark basin near Riegelsville, Pennsylvania, on the basis of a Vibroseis profile and two continuously cored drill holes across faults at the basin margin. A group of moderately strong planar reflections in a zone 0.5 km thick in gneiss and carbonate rocks of the footwall block coincides with the updip projection of imbricate fault slices and mylonites associated with the Musconetcong thrust system of Drake et al. (1967). Contrasts in acoustic impedance among mylonitic dolostone and mylonitic gneiss and their protoliths, determined from measurements on samples from a third cored hole, are sufficiently large to account for reflections seen in the footwall block. Analysis of drill core and surface outcrops supports the conclusion that low-angle extensional faulting in the early Mesozoic was localized by reactivation of Paleozoic imbricate thrust faults in the basement rocks. Extension in the northwest-southeast quadrant was approximately perpendicular to the strike of the ancient thrust faults in eastern Pennsylvania. The data presented here are the most explicit three-dimensional information obtained thus far in the eastern US in support of the concept of fault reactivation in controlling formation of early Mesozoic extensional basins.},
doi = {10.1130/0091-7613(1986)14<766:LEFRMA>2.0.CO;2},
url = {https://www.osti.gov/biblio/5717848}, journal = {Geology; (United States)},
number = ,
volume = 14:9,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 1986},
month = {Mon Sep 01 00:00:00 EDT 1986}
}