Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Sea level, synsedimentary tectonics, and reefs; implications for hydrocarbon exploration in the Silurian-lowermost Devonian Gaspe Belt, Quebec Appalachians

Pierre-Andre Bourque
Sea level, synsedimentary tectonics, and reefs; implications for hydrocarbon exploration in the Silurian-lowermost Devonian Gaspe Belt, Quebec Appalachians (in Hydrocarbon plays in the Silurian-Devonian Gaspe Belt, Quebec, Appalachians, Denis Lavoie (editor) and Pierre-Andre Bourque (editor))
Bulletin of Canadian Petroleum Geology (June 2001) 49 (2): 217-237

Abstract

Sea-level changes and synsedimentary tectonics affected the development of three potential hydrocarbon reservoir intervals in the Silurian-lowermost Devonian part of the Gaspe Belt on the margin of Laurentia. A relative sea-level curve is based on sequence analysis of facies and distribution of benthic faunas. The succession recorded two major, low-order sedimentary cycles, each composed of a regressive-transgressive couplet and represented by shallowing- and deepening-upward sequences. The first shallowing episode (S (sub 1) ) covered the Rhuddanian-Sheinwoodian (Llandovery-early Wenlock) interval, whereas a rapid deepening episode (D (sub 1) ) followed during the Homerian (late Wenlock). A second shallowing episode (S (sub 2) ) started during the late Homerian, and ended in the late Ludfordian (late Ludlow) or earliest Pridolian, and was then followed by a latest Silurian-Early Devonian deepening episode (D (sub 2) ). Potential reservoir rock units developed mostly during sea-level lowstands or early transgressions in the Gaspe Belt. Comparison of the Gaspe relative sea-level curve with eustatic curves, proposed for the same time interval, indicates that the Gaspe curve was significantly influenced by local synsedimentary tectonics. Salinic extensional tectonics, a predominantly Late Silurian-Early Devonian (Ludlovian-Pragian) event, resulted in block faulting and tilting along normal listric faults. Interaction between block faulting and eustatic sea-level fall at the end of the Ludlovian-early Pridolian exposed the highest parts of the blocks to subaerial erosion and diagenesis, and allowed reefs and reef complexes to settle at the margins of the blocks, or on erosional remnants. Salinic extensional tectonics may also have provided suitable pathways for hydrocarbon migration and charge at various times during the mid-Silurian to Early Devonian, particularly for hydrocarbons that may have been generated in the underlying Cambro-Ordovician shales. In the northeastern part of the Gaspe Belt, which is the most promising area for hydrocarbon reservoirs in the Gaspe Peninsula, block faulting and tilting have changed the fluid migration pattern from an updip-northeastward flow from the basin centre to basin margin during the Late Ordovician to early Late Silurian, to a potential updip-southwestward flow in each faulted block during the early Late Silurian. Basin tectonics may have played a significant role in driving hydrocarbon-rich fluids toward potential reservoirs, such as the Llandoverian Val-Brillant sandstone bodies, the Sayabec carbonate sands and knob reefs, or the West Point reefs.


ISSN: 0007-4802
Coden: BCPGAI
Serial Title: Bulletin of Canadian Petroleum Geology
Serial Volume: 49
Serial Issue: 2
Title: Sea level, synsedimentary tectonics, and reefs; implications for hydrocarbon exploration in the Silurian-lowermost Devonian Gaspe Belt, Quebec Appalachians
Title: Hydrocarbon plays in the Silurian-Devonian Gaspe Belt, Quebec, Appalachians
Author(s): Bourque, Pierre-Andre
Author(s): Lavoie, Deniseditor
Author(s): Bourque, Pierre-Andreeditor
Affiliation: Universite Laval, Departement de Geologie et de Genie geologique, Quebec City, QC, Canada
Affiliation: Geological Survey of Canada, Centre Geoscientifique de Quebec, Quebec, QC, Canada
Pages: 217-237
Published: 200106
Text Language: English
Summary Language: French
Publisher: Canadian Society of Petroleum Geologists, Calgary, AB, Canada
References: 64
Accession Number: 2003-075642
Categories: Economic geology, geology of energy sourcesStratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sect., strat. cols., geol. sketch map
N47°49'60" - N49°15'00", W68°00'00" - W64°15'00"
Secondary Affiliation: Universite Laval, CAN, Canada
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 200323
Close Modal

or Create an Account

Close Modal
Close Modal