Grenville foreland thrust belt hidden beneath the eastern US midcontinent

Journal Article · Fri Jan 01 00:00:00 EST 1993 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1993)021<0061:GFTBHB>2.3.CO;2· OSTI ID:6043181

Hauser, E C ^[1]

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1. Cornell Univ., Ithaca, NY (United States)

Grenville foreland thrust structures are observed beneath the eastern US midcontinent on COCORP (Consortium for Continental Reflection Profiling) line OH-1 and a short seismic line in southwest Ohio. These structures represent the first evidence for a significant Grenville foreland thrust belt preserved in eastern North America. On the COCORP lines, the structures include a thrust ramp anticline and an associated asymmetric syncline. The Grenville front tectonic zone appears to truncate these foreland structures, indicating a later, second phase expressed as a deeply penetrating, out-of-sequence thrust zone associated with the main uplift of the Grenville province on the east. A short, shallow seismic line in southwestern Ohio reveals an east-dipping sequence of prominently layered rocks that may lie above a footwall ramp to a deeper Grenville thrust fault. A drill hole into the less reflective top of this dipping sequence encountered unmetamorphosed sedimentary rocks like those increasingly reported from other drill holes in southwestern Ohio and adjacent states. Although possibly part of a late Precambrian (Keweenawan ) rift, these clastic sedimentary rocks may instead preserve evidence of a heretofore unrecognized Grenville foreland basin in eastern North America. Alternatively these Precambrian sedimentary rocks together with an underlying, but yet undrilled, strongly layered sequence may correlate with similarly layered rocks observed on COCORP and industrial seismic lines within the Middle Proterozoic granite-rhyolite province to the west in Indiana and Illinois and indicate that unmetamorphosed sedimentary material is an important constituent of the granite-rhyolite province. 25 refs., 6 figs.

• DOE Contract Number: FG21-91MC28136
• OSTI ID: 6043181
• Journal Information: Geology; (United States), Vol. 21:1; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
47 OTHER INSTRUMENTATION
US EAST COAST
SEISMIC SURVEYS
ANTICLINES
GEOLOGY
LITHOLOGY
OROGENESIS
TECTONICS
DEVELOPED COUNTRIES
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
NORTH AMERICA
PETROLOGY
SURVEYS
USA
580000* - Geosciences
440700 - Geophysical &amp; Meteorological Instrumentation- (1990-)