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GEOREF RECORD

Lower Paleozoic foreland basins in Eastern Canada; tectono-thermal events recorded by faults, fluids and hydrothermal dolomites

Denis Lavoie and Guoxiang Chi
Lower Paleozoic foreland basins in Eastern Canada; tectono-thermal events recorded by faults, fluids and hydrothermal dolomites (in International Lithosphere Programme's Quebec City workshop, Donna Kirkwood (prefacer), Michel Malo (prefacer), Denis Lavoie (prefacer) and Kirk G. Osadetz (prefacer))
Bulletin of Canadian Petroleum Geology (March 2010) 58 (1): 17-35

Abstract

Dolomites in Lower and Middle Ordovician and Lower Silurian carbonates in Anticosti and Gaspe, respectively, are documented petrographically and geochemically to originate from early replacement and later void-filling phases, both derived from high temperature brines. These dolomite-rich intervals are interpreted as hydrothermal dolomites that formed during the early phases of foreland basin development along the continental margin of Laurentia; the Ordovician examples are related to the Taconian Orogeny whereas the Lower Silurian one is associated with the Salinic Orogeny. The dolomitization of the Lower and Middle Ordovician carbonates on Anticosti platform occurred shortly after the demise of shallow marine carbonate sedimentation in early Late Ordovician, at a time of significant increase of subsidence rates and associated higher geothermal gradients along the entire continental margin of Laurentia. Two geochemically different fluids are documented; the differences could be related to more pronounced rock-water interactions for the Lower Ordovician carbonates. The dolomitization of the Lower Silurian carbonates on Gaspe Peninsula is demonstrated to be an early event, pre-Late Silurian, which occurred during a significant magmatic period and likely high geothermal gradients. The Lower Silurian hydrothermal dolomites record significant exchanges between the high temperature fluid and the mafic to ultramafic basement that supplied large volumes of Mg (super +2) needed for this regional alteration. This paper illustrates the tectonic link between active foreland basin and hydrothermal dolomite. Moreover, the efficiency of fault-controlled circulation related to upward thermal convection of dolomitizing fluids is possibly enhanced at times of significant magmatic and thermal episodes along the continental convergent margins.


ISSN: 0007-4802
Coden: BCPGAI
Serial Title: Bulletin of Canadian Petroleum Geology
Serial Volume: 58
Serial Issue: 1
Title: Lower Paleozoic foreland basins in Eastern Canada; tectono-thermal events recorded by faults, fluids and hydrothermal dolomites
Title: International Lithosphere Programme's Quebec City workshop
Author(s): Lavoie, DenisChi, Guoxiang
Author(s): Kirkwood, Donnaprefacer
Author(s): Malo, Michelprefacer
Author(s): Lavoie, Denisprefacer
Author(s): Osadetz, Kirk G.prefacer
Affiliation: Geological Survey of Canada, Quebec Division, Quebec City, QC, Canada
Affiliation: Geological Survey of Canada, Quebec City, QC, Canada
Pages: 17-35
Published: 20100301
Text Language: English
Summary Language: French
Publisher: Canadian Society of Petroleum Geologists, Calgary, AB, Canada
Meeting name: International Lithosphere Programme's Quebec City workshop
Meeting location: Quebec City, QC, CAN, Canada
Meeting date: 20060918Sept. 18-22, 2006
References: 112
Accession Number: 2010-070316
Categories: Economic geology, geology of energy sourcesStructural geology
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., 3 tables, sketch maps
N47°49'60" - N49°15'00", W68°00'00" - W64°15'00"
N49°04'00" - N49°57'00", W64°31'60" - W61°43'00"
Secondary Affiliation: Institut National de la Recherche Scientifique, CAN, Canada
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Canadian Society of Petroleum Geologists. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201038
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