Geophysical modeling of the structural relationships between the Precambrian Reading Prong rocks and the Paleozoic sedimentary sequence, Easton quadrangle, PA

Conference · Mon Mar 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5639926

Thomas, D M; Malinconico, Jr, L L ^[1]

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1. Lafayette Coll., Easton, PA (United States). Dept. of Geology

This project involves the geophysical modeling of the structural relationships between the Precambrian Reading Prong rocks and the Paleozoic sedimentary cover rocks near Easton, Pennsylvania. The Precambrian rocks have generally been assumed to have been emplaced on the Paleozoic sequence along a shallow thrust fault. However, at present time the attitude of the faults bordering the Precambrian terranes are all very steeply dipping. This was explained by the subsequent folding of the whole sequence during later orogenic activity. The objective of this work is to determine the attitude and depth of the fault contact between the Precambrian crystalline rocks and the Paleozoic sedimentary rocks. A series of traverses (each separated by approximately one mile) were established perpendicular to the strike of the Precambrian rocks. Along each traverse both gravity and magnetic readings were taken at 0.2 kilometer intervals. The data were reduced and presented as profiles and contour maps. Both the magnetic and gravity data show positive anomalies that correlate spatially with the location of the Precambrian rocks. The gravity data have a long wavelength regional trend increasing to the north with a shorter wavelength anomaly of 2 milligals which coincides with the Precambrian rocks. The magnetic data have a single positive anomaly of almost 1,000 gammas which also coincides with the Precambrian terrane. These data will now be used to develop two dimensional density and susceptibility models of the area. From these models, the thickness of each formation and the structural relationships between them, as well as the attitude and depth of the fault contact will be determined.

• OSTI ID: 5639926
• Report Number(s): CONF-9303211-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GEOLOGIC FAULTS
GRAVITY SURVEYS
MAGNETIC SURVEYS
GEOLOGIC FORMATIONS
DATA ANALYSIS
PENNSYLVANIA
BASEMENT ROCK
GEOLOGIC HISTORY
GEOLOGIC MODELS
MAGNETIC SUSCEPTIBILITY
MAPPING
ORIENTATION
PRECAMBRIAN ERA
SEDIMENTARY ROCKS
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
MAGNETIC PROPERTIES
NORTH AMERICA
PHYSICAL PROPERTIES
ROCKS
SURVEYS
USA
580000* - Geosciences