Stratigraphy of Continental Shelf, Offshore Nova Scotia: ABSTRACT

Abstract

A formal stratigraphic scheme has been proposed for the Cenozoic and Mesozoic sediments of the continental shelf, offshore Nova Scotia. The stratigraphy is based primarily on subsurface information from approximately 30 offshore wells and supplemented by an extensive seismic grid. The oldest recognized stratigraphic unit is salt, possibly of Early Jurassic age. The salt unit thickens into several subbasins where it is overlain conformably by a variable sequence of dolomite, anhydrite, limestone, and shale. Poorly sorted, feldspathic clastic sedimentary rocks disconformably overlie the evaporite section End_Page 2147------------------------------ as well as adjacent basement rocks consisting of metasediments and granite. The basal clastic rocks are overlain by a group of limestones and associated shales deposited during widespread marine transgression. This carbonate-shale sequence is overlain by several thousand feet of deltaic to interdeltaic sands and shales of Late Jurassic and Cretaceous age. Sand deposition decreased gradually in Late Cretaceous time as the shelf was completely submerged. The overlying group of Cretaceous to Tertiary shales, thin limestones, chalk, and argillaceous sands was deposited in relatively deep water. Percent of fine sand increases gradually toward the top of the section as water depths decreased. The Tertiary sediments are eroded deeply and unconformably overlain by highly variable Pleistocene clastic rocks. End_of_Article - Last_Page 2148------------