Partitioning of the Taconic foreland basin: Middle to Late Ordovician flysch and molasse sub-basins of New York State and Ontario

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5588517

Lehmann, D; Brett, C E; Ingram, S L ^[1]

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1. Univ. of Rochester, Rochester, NY (United States). Dept. of Geological Sciences

Analysis of field and well data suggest that the foreland basin in New York and Ontario is divisible into two sub-basins containing siliciclastic fill which are separated by a moderately narrow, north/south oriented region of relatively thin siliciclastic strata. The eastern sub-basin contains a thick succession of late Middle and early Late Ordovician basinal black shales and turbiditic siltstones and sandstones (flysch). These strata thicken eastward to over 800 m beneath the thrust belt (Taconic allochthon) in the eastern most portion of the sub-basin. The flysch is, at least in part, time-correlative with ramp carbonates present in the western sub-basin. The western sub-basin contains a relatively thin succession of flysch deposits that overlie Upper Ordovician carbonates. The flysch deposits from the western sub-basin correlate with only the stratigraphically highest strata in the eastern sub-basin. In the western sub-basin, flysch deposits are overlain by Upper Ordovician shallow marine to non-marine mudstones and sandstones (molasse). The molasse is unconformably overlain by Lower Silurian strata. Due to the angularity of the unconformity surface, the molasse is stratigraphically most complete towards the western margin of the western sub-basin; thickest deposits in this sub-basin ([gt] 600 m) are not the most stratigraphically complete. The general sedimentary history of the New York portion of the Taconic siliciclastic wedge is bipartite: (1) rapid subsidence in the eastern sub-basin during the late Middle and early Late Ordovician accompanied by flysch-phase filling; (2) rapid subsidence in the western sub-basin during the middle to late Late Ordovician accompanied by molasse-phase filling.

• OSTI ID: 5588517
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
BLACK SHALES
CANADA
DEPOSITION
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
GROUND SUBSIDENCE
NEW YORK
NORTH AMERICA
ONTARIO
ORDOVICIAN PERIOD
PALEOZOIC ERA
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SHALES
SILTSTONES
STRATIGRAPHY
USA