ABSTRACT: Tectonic Controls on Sequence Development in the Late Turinian to Early Edenian (Ordovician) of Eastern North America

MITCHELL, C. E., and JOY, M. P., Dept. of Geology, SUNY at Buffalo, NY ([email protected]); ADHYA, S., and DELANO, J. W., Dept. of Earth and Atmospheric Sciences, SUNY at Albany, NY; BERGSTROM, STIG M., Dept. of Geological Sciences, Ohio State Univ., Columbus, OH

We have utilized a precise chronostratigraphic framework (based on graphic correlation of K-bentonite isochrons, graptolite and conodont range data) to investigate the synchroneity of the major architectural elements of stratigraphic sequences in the late Turinian to early Edenian of Eastern North America. Episodes of rapid accommodation space growth, black shale overstep, and marine hiatus formation in the Taconic Basin coincided with episodes of emergence that form sequence boundaries in the region of the Nashville Dome, Tennessee, and Jessamine Dome, Kentucky. Chatfieldian cratonic and basinal sequences lack lowstand systems tract deposits. Their absence up-dip reflects the fact that the lowstand interval was a product of local uplift on the Taconic forebulge, not a basin-wide change in accommodation space. Within the Taconic Basin, the interval of forebulge emergence is represented by a transgressive systems tract formed in response to tectonic deepening of the basin. Shelf margin systems tract-like deposits may be present near the flexural hinge between the forebulge and foreland basin. Although a eustatic component may also be present, accommodation space changes during the late Turinian to early Edenian appear to be primarily a response to tectonically driven changes in lithospheric elevation.

MITCHELL, C. E., JOY, M. P., ADHYA, S., DELANO, J. W., BERGSTROM, STIG M.,

Search and Discovery Article #90907©2000 AAPG Eastern Section Meeting, London, Ontario, Canada