ABSTRACT: Application of Sequence Stratigraphic Concepts to the Paleozoic/Mesozoic Succession of Ontario: Insights and Problems

ARMSTRONG, DEREK K., Ontario Geological Survey, Sudbury, Ontario, Canada

The application of sequence stratigraphic concepts to the Paleozoic and Mesozoic succession of Ontario has provided insights into the relationships between sedimentation and tectonic activity. This succession in Ontario has been subdivided into ten depositional sequences, defined as packages of genetically related sediments, largely bounded by unconformities. The boundaries of some of these sequences correspond to continent-wide sequence boundaries, whereas others indicate more localized (basin-scale) controls.

Tectonic controls on sedimentation are evidenced by depositional and erosional patterns. Wedges of orogen-derived clastics correlate with major (and minor) episodes of orogenic uplift. Craton-derived clastics reflect uplift of interbasinal arch areas. Evaporite-dominated intervals indicate basin restriction. Carbonate-dominated intervals indicate relative tectonic quiescence. Erosional patterns vary from craton-wide to arch-centered unconformities and reflect different scales and styles of uplift. Local depositional/erosional patterns suggest that some cratonic tectonism was accommodated by brittle deformation (i.e., fracture-framework systems).

Correlation of these sequences among the four sedimentary basins, in or adjacent to Ontario, affords a comparison of sedimentation in various tectonic settings (e.g., foreland and intracratonic basins, interbasinal arches) and helps to refine constraints on basin development/subsidence models. Some of these models suggest linkage of cratonic and plate margin tectonism. Higher resolution chrono/biostratigraphy is required for more detailed correlation of depositional/erosional events on the craton with tectonic events at the plate margin. In addition, more basic data are required from certain stratigraphic intervals and geographic areas (e.g., Hudson Bay basin) to facilitate more accurate correlations.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)