Hydrothermal dolomitization in the Lower Ordovician Romaine Formation of the Anticosti Basin: significance for hydrocarbon exploration

Abstract

Research Article| December 01, 2005 Hydrothermal dolomitization in the Lower Ordovician Romaine Formation of the Anticosti Basin: significance for hydrocarbon exploration D. Lavoie; D. Lavoie Ressources Naturelles du Canada, Geological Survey of Canada, 490, rue de la Couronne, Québec, QC G1K 9A9, [e-mail] 1Current address: Department of Geology, University of Regina, Regina, SK Search for other works by this author on: GSW Google Scholar G. Chi; G. Chi Ressources Naturelles du Canada, Geological Survey of Canada, 490, rue de la Couronne, Québec, QC G1K 9A9, [e-mail] Search for other works by this author on: GSW Google Scholar P. Brennan-Alpert; P. Brennan-Alpert Department of Geological Sciences, University of Ottawa, Ottawa, ON K1N 6N5 Search for other works by this author on: GSW Google Scholar A. Desrochers; A. Desrochers Department of Geological Sciences, University of Ottawa, Ottawa, ON K1N 6N5 Search for other works by this author on: GSW Google Scholar R. Bertrand R. Bertrand Institut National de la, Recherche Scientifique, Eau-Terre-Environnement, 490, rue de la Couronne, Québec, QC G1K 9A9 Search for other works by this author on: GSW Google Scholar Author and Article Information D. Lavoie 1Current address: Department of Geology, University of Regina, Regina, SK Ressources Naturelles du Canada, Geological Survey of Canada, 490, rue de la Couronne, Québec, QC G1K 9A9, [e-mail] G. Chi Ressources Naturelles du Canada, Geological Survey of Canada, 490, rue de la Couronne, Québec, QC G1K 9A9, [e-mail] P. Brennan-Alpert Department of Geological Sciences, University of Ottawa, Ottawa, ON K1N 6N5 A. Desrochers Department of Geological Sciences, University of Ottawa, Ottawa, ON K1N 6N5 R. Bertrand Institut National de la, Recherche Scientifique, Eau-Terre-Environnement, 490, rue de la Couronne, Québec, QC G1K 9A9 Publisher: Canadian Society of Petroleum Geologists Received: 09 May 2005 Accepted: 03 Oct 2005 First Online: 02 Mar 2017 Online ISSN: 2368-0261 Print ISSN: 0007-4802 © The Society of Canadian Petroleum Geologists Bulletin of Canadian Petroleum Geology (2005) 53 (4): 454–471. https://doi.org/10.2113/53.4.454 Article history Received: 09 May 2005 Accepted: 03 Oct 2005 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation D. Lavoie, G. Chi, P. Brennan-Alpert, A. Desrochers, R. Bertrand; Hydrothermal dolomitization in the Lower Ordovician Romaine Formation of the Anticosti Basin: significance for hydrocarbon exploration. Bulletin of Canadian Petroleum Geology 2005;; 53 (4): 454–471. doi: https://doi.org/10.2113/53.4.454 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of Canadian Petroleum Geology Search Advanced Search Abstract This study deals with the diagenetic evolution of dolostones of the Romaine Formation, from cores and outcrops on Anticosti and Mingan islands, and reports evidence for hydrocarbon migration in secondary porosity generated by high temperature / hydrothermal alteration. Four types of calcite (grouped into early (C1) and late (C2) assemblages) and six types of dolomite (grouped into 3 different (D1, D2 and D3) assemblages) are distinguished. According to fluid-inclusion and stable C-O isotope data, the early calcite group, which consists of sedimentary micrite, replacement microspar and early pore-filling calcite records near surface diagenetic environments. Early and pervasive replacement dolomites (RD1 and RD2 in the first dolomite (D1) assemblage) were formed during early burial, and are not related to porosity generation. Later replacement dolomites (RD3 and RD4 in the second dolomite (D2) assemblage) and pore-filling dolomite cements (PD1 and PD2 in the third dolomite (D3) assemblage) as well as minor sphalerite were formed from warm, saline fluids, which were likely hydrothermal in origin. Vuggy porosity was produced through brecciation and fracturing, and through some dissolution of the D1 dolomite assemblage by these hydrothermal fluids. Intercrystalline porosity was also created during formation of the D2 dolomite assemblage. The vugs were partly occluded by late-stage pore filling dolomite and calcite cements, pyrite and barite. Bitumen droplets in vugs together with hydrocarbon inclusions recorded in C2 calcite and in contemporaneous barite indicate a hydrocarbon migration event after the porosity-generating processes.The brecciation / leaching of a precursor dolomite host is uncommon in hydrothermal dolomite hydrocarbon fields, but is recognized in the adjacent coeval pool in Newfoundland. This type of alteration in the Ordovician carbonates with the presence of a rich hydrocarbon source rock and favourable maturation are key elements for the on-going exploration efforts in this basin. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.