ABSTRACT

Geologic data from 29 wells in the Baltimore Canyon Trough were released to the public as of 1982, and provide sufficient information for establishing Upper Jurassic through Cenozoic rock-stratigraphic units. Most of the units are lithologically similar to formations on the Scotian Shelf and are, therefore, considered in this study to be the Scotian Shelf homotaxial equivalents. The oldest rocks penetrated by exploratory wells in the Baltimore Canyon Trough are of Late Jurassic age and are correlative to the Scotian Shelf Mohawk, Mic Mac, and Abenaki Formations.

The Mohawk(?) sandstone and Mic Mac shale equivalents in the Baltimore Canyon Trough represent lower delta plain to predominantly prodelta environments, and the Abenaki-equivalent limestone represents a shelfmargin carbonate buildup. Delta progradation continued during the Early Cretaceous, and lower delta-plain and delta-front sand and shale, equivalent to the Scotian Shelf Missisauga Formation, were deposited. A destructional phase of the delta is represented by the Naskapi equivalent, a calcareous shale. Inundation by the sea was incomplete, however, and channel and distributary-mouth-bar sands (Logan Canyon equivalent) were deposited. A final marine transgression began during the Late Cretaceous and resulted in the deposition of mudstone, which is considered equivalent to the Scotian Shelf Dawson Canyon Formation. Marine conditions prevailed through much of the remainder of the Cretaceous and Cenozoic in both the Scotian Shelf and Baltimore Canyon Trough areas. Lithologic similarities between Cenozoic units of the Scotian Shelf and Baltimore Canyon Trough are less significant.Although both basins exhibit an upward increase in sand content, the Scotian Shelf Cenozoic strata are more sandy than those in the Baltimore Canyon Trough. In ascending order, the Baltimore Canyon Trough Cenozoic section consists of the uppermost Dawson Canyon equivalent, a chalk unit, a mudstone unit, an unconsolidated sand unit, and an uppermost clay unit.

Stratigraphic traps may be present in the Baltimore Canyon Trough Upper Jurassic and Lower Cretaceous deltaic sandstones and shelf-margin carbonates. The deltaic units contain channel and distributary-mouth-bar sandstones, which may be potential reservoirs. Seals may be formed by lateral and vertical contacts against the prodelta, interdistributary bay, and marine shales. The Abenaki stratigraphic-reef trend provides another potential target. Source rocks, reservoir rocks, and traps may be associated with the trend, but its potential can only be defined by future drilling.

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