Cryptalgalaminate dolomite of the Dunphy Formation, Labrador Trough; diagenetic and tectono-metamorphic evolution related to copper mineralization

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doi: 10.1139/e85-195
Authors:Chevé, S. R.; Schrijver, K.; Tassé, N.
Author Affiliations:Primary:
INRS-Géoressour., Sainte-Foy, QC, Canada
Volume Title:Canadian Journal of Earth Sciences Revue Canadienne des Sciences de la Terre
Source:Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre, 22(12), p.1835-1857. Publisher: National Research Council of Canada, Ottawa, ON, Canada. ISSN: 0008-4077
Publication Date:1985
Note:In English with French summary. 59 refs.; illus. incl. 4 tables, geol. sketch maps
Summary:The strata-bound Cu-Fe-S mineralization of this Lower Proterozoic formation forms the largest known sediment-hosted Cu deposit of the Labrador Trough. Occurring in three thin stratiform intervals, the sulphides are mainly: 1) disseminated in a primary porosity cemented by dolospar; 2) vein-bound in early tectonic spar-filled tension gashes. The history of cementation of the host dolomite of one of the intervals was traced by cathodoluminoscopy. Four concentric rim cements are followed by two to three central cements. Probe analyses show increasing Fe and Mn in solid solution in these cements from rim to centre, pointing to a decrease in Eh towards the centre during cementation. The degradation of Recent cyanobacterial mats is used as a model for the diagenetic evolution of the dolomite. The fenestral fabrics of the mats were the major channels for cement-forming substances and the only channels that governed the lateral component of movement of major pulses of metalliferous fluids. [P.Br.]
Subjects:Biogenic processes; Carbonate rocks; Carbonatization; Cementation; Copper ores; Diagenesis; Disseminated deposits; Dolomitization; Dolostone; Economic geology; Geochemical controls; Host rocks; Metal ores; Metamorphism; Mineral deposits, genesis; Paleoproterozoic; Precambrian; Proterozoic; Sedimentary rocks; Stratabound deposits; Structural controls; Tectonics; Textures; Upper Precambrian; Veins; Canada; Canadian Shield; Churchill Province; Eastern Canada; Labrador Trough; North America; Quebec; Superior Province; Dunphy Formation; Romanet Lake; Sedimentary processes
Coordinates:N561500 N563000 W0674500 W0681500
Abstract Numbers:86M/4967
Record ID:1986011193
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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