| Paper No. 98-0 | ||
| TIMING CONSTRAINTS AND PARAGENESIS OF MINERALIZING EVENTS AT THE CRESTAURUM GOLD DEPOSIT, YELLOWKNIFE GREENSTONE BELT, NWT, CANADA | ||
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OOTES, Luke1, LENTZ, David R.1, and CREASER, Robert A.2, (1) Department of Geology, Univ of New Brunswick, P.O. box 4400, Fredericton, NB E3B 5A3, Canada, ootes@unb.ca, (2) Department of Earth and Atmospheric Sciences, Univ of Alberta, 1-26 Earth Science Bldg, University of Alberta, Edmonton, AB T6G 2E3, Canada The Crestaurum shear zone-hosted lode gold deposit is located 14km north of Yellowknife, Northwest Territories, Canada, in the late Archean Yellowknife Greenstone Belt of the southwestern Slave Structural Province. The 035°/55° SE shear zone transects metamorphosed basalts (ca. >2722 Ma), mixed felsic volcaniclastics, and post-volcanic gabbro and QFP dikes (ca. 2670 Ma). The metamorphic grade of the host rocks are greenschist to the east and transitional to amphibolite grade towards a polyphase tonalite to the west. The shear zone has a reverse sense of movement as indicated by steeply pitching stretching lineations, boudinaged quartz veins, and C-S fabric relationships. Regional and local fabric relationships confine the mineralization to syn- to late-D2 (~2590 Ma). Multiple layered quartz veins and multiple generations of mineralization are evidence for a composite history. Sulfide mineralization in the gold-bearing quartz and quartz-carbonate veins include pyrite + stibnite + arsenopyrite + sulfosalts ± sphalerite ± chalcopyrite. Visible gold is physically and chemically associated with pyrite, stibnite, and sulfosalts. Refractory gold is associated with arsenopyrite. Host rock alteration in the shear zone includes carbonate + pyrite + chlorite ± sericite ± biotite ± tourmaline. Other gold-bearing quartz veins in the area trend at 270° and are base-metal rich. They contain sphalerite + galena + pyrrhotite + pyrite ± arsenopyrite ± chalcopyrite and reflect a separate mineralizing event from the Crestaurum Shear Zone. Early mineralizing events in the area include syn-volcanic pyrite + pyrrhotite stockworks, magnetite-bearing banded iron formation, and post-volcanic quartz vein-hosted molybdenite within the tonalite west of the Crestaurum Shear Zone. This molybdenite mineralization has been dated by Re-Os at ca. 2680 ± 19 Ma and is significantly older than the syn- to late-D2 Crestaurum mineralization. On the local scale, these older mineralizing events are candidates as proto-ores for the Crestaurum deposit. | ||
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GSA Annual Meeting, November 5-8, 2001
General Information for this Meeting | ||
| Session No. 98--Booth# 84 Sigma Gamma Epsilon Student Research Poster Session (Posters) Hynes Convention Center: Hall D 1:30 PM-5:30 PM, Tuesday, November 6, 2001 | ||
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