Stratified precambrian rocks (sedimentary ) beneath the midcontinent region of the US
A thick sequence of layered rocks occurs beneath the Phanerozoic platform strata which blanket the US midcontinent. Observed on COCORP deep reflection data in southern Illinois and Indiana and in SW Oklahoma and adjacent Texas, this sequence is locally 1--3 times as thick as the overlying Paleozoic cover, but the origin of this sequence and its ultimate lateral extent are unknown. However, the occurrences of Precambrian layered rocks on both the COCORP profiles and reprocessed industry seismic reflection data from the region lie within regions of generally low amplitude and low frequency aeromagnetic anomaly, suggesting an even greater distribution. Unmetamorphosed Precambrian sedimentary rocks have been recovered from drill holes in southwest Ohio and adjacent northern Kentucky and southwesternmost Indiana. These Precambrian sedimentary rocks lie above and may be part of an underlying package of strongly layered rocks imaged on a short and shallow seismic profile in southwest Ohio. These Precambrian sedimentary rocks were originally viewed as part of a late Precambrian (Keweenawan ) rift; however, in light of Grenville foreland structures seen on the COCORP profile to the north in west central Ohio, these Precambrian strata may (1) be part of a heretofore unrecognized Grenville foreland basin, or (2) indicate that unmetamorphosed Precambrian sedimentary material may be an important constituent of the layered rocks observed on COCORP beneath southern Illinois and Indiana.
- Research Organization:
- Cornell Univ., Ithaca, NY (United States). Inst. for the Study of the Continents
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG21-91MC28136
- OSTI ID:
- 6328369
- Report Number(s):
- DOE/MC/28136-3373; ON: DE93018032
- Country of Publication:
- United States
- Language:
- English
Similar Records
Grenville foreland thrust belt hidden beneath the eastern US midcontinent
Deep crustal sediment study: Widespread Precambrian layered rocks (Sedimentary ) beneath the US midcontinent
Related Subjects
03 NATURAL GAS
ILLINOIS
STRATIGRAPHY
INDIANA
KENTUCKY
OHIO
OKLAHOMA
SEDIMENTARY ROCKS
SEISMIC SURVEYS
TEXAS
MAPS
PRECAMBRIAN ERA
PROGRESS REPORT
RESOURCE ASSESSMENT
RIFT ZONES
DEVELOPED COUNTRIES
DOCUMENT TYPES
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
GEOPHYSICAL SURVEYS
NORTH AMERICA
ROCKS
SURVEYS
USA
580000* - Geosciences
030200 - Natural Gas- Reserves
Geology
& Exploration