--> --> Abstract: Thermal Maturation and Hydrocarbon Potential of Ordovician to Devonian Rocks in Northwestern New Brunswick, by Rudolf Bertrand, Michel Malo, and Denis Lavoie; #90039 (2005)
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Thermal Previous HitMaturationNext Hit and Hydrocarbon Potential of Ordovician to Devonian Rocks in Northwestern New Brunswick

Rudolf Bertrand1, Michel Malo2, and Denis Lavoie3
1 Institut National de la Recherche Scientifique (INRS-Eau, Terre et Enrironnement), Québec, QC
2 Institut National de la Recherche Scientifique (INRS Eau-Terre-Environnement), Quebec, QC
3 Geological Survey of Canada, Quebec City, QC

Organic matter petrography and geochemistry is carried out on 160 samples from lower and middle Paleozoic rocks in northwestern New Brunswick. The successions form part of a successor basin that unconformably overlies Cambrian-Ordovician basement rocks of the Appalachians Dunnage and Gander zones. The successions crop out in three fault-bounded structural elements, from south to north, the Chaleurs Bay synclinorium, the Aroostook-Percé anticlinorium and the Gaspé-Connecticut Valley synclinorium. They comprise successions mostly dominated by siliciclastic sediments that cover the Upper Ordovician to Middle Devonian interval. Two folding episodes are recognized.

Sedimentary burial plays a critical role in the thermal Previous HitmaturationNext Hit of these successions although, this burial is highly variable from one area to the other. These rock successions cover a wide range of vitrinite reflectance values (0.36% to 8.9%) and thermal Previous HitmaturationNext Hit ranks (immature zone to greenschist facies), whatever their position in the sedimentary pile. Areas favourable for oil preservation are limited to tectonic blocks bordered by major faults, these blocks were positive elements during the Silurian-Early Devonian Salinian Disturbance. The thermal Previous HitmaturationTop post-dates the first NW-SE folding phase of the area, is coeval with the second NE-SW folding phase but pre-dates the major strike-slip faulting.

Modelling the hydrocarbon generation allows proposing that the principal source rocks of the area, the Middle Ordovician Popelogan Formation of the underlying Dunnage zone and the Ritchie Brook Member of the Boland Brook Formation (Upper Ordovician) generated most of their oil before the Salinian Disturbance, making this sector highly prospective for hydrocarbons.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005