In Eastern Canada, in a regional Carboniferous rift system (Maritimes Basin
Tectonostratigraphic Zone), there are lacustrine basins containing petroliferous source
rocks. Near the northern limits for this complex, strata of the Cape Rouge Formation at
Conche, Newfoundland, are thought to represent a nearby onshore facies analog for rocks
laying farther offshore in the St. Anthony Basin.
Four facies assemblages of mixed sandstone, siltstone, dolostone and black
mudstone represent distinct stages of an underfilled lake-basin developed within a half-graben
depocenter. The finest-grained facies assemblage, with TOC between 0.23-6.54
wt.%, has organic matter dominated by Type 1 kerogen. Maturation analysis places strata
within the oil-generation window (Rₒ=0.5-1.01%); however, Rock-Eval results indicate
little remaining potential for generating hydrocarbons. Based on findings from Conche,
the St. Anthony Basin may contain similar half-graben lake-basins with Carboniferous
source rock potential. However, source quality and timing for oil generation remain key
risks for hydrocarbon exploration offshore
