71 Economic and Energy Geology (Posters)

Tuesday, 21 March 2017
1:30 PM - 5:30 PM
Urban, 17th Floor

ORIGIN AND ECONOMIC VIABILITY OF THE ROSE BLANCHE QUARTZ-GOLD BODY, NEWFOUNDLAND

Paper number: 71-5
Program: Technical Sessions
Time: 1:30 PM – 5:30 PM

Authors

Abstract

Gold deposits are well documented throughout the Appalachians from the Carolinas to Newfoundland. Newfoundland gold deposits are believed to have formed as a result of convergence between Laurentian and Gondwanan continents and the entrapment of Cambro-Ordovician island arc and ophiolitic terranes that make up the Dunnage Tectonic Zone (Wardle, 2005). The alteration of carbonates within the mesothermal deposit and the presence of CO2 rich fluids inclusions implies that gold mineralization could also have formed from metamorphic fluids in intrusive bodies (Wardle, 2005). The Rose Blanche gold prospect has been considered a possible gold deposit for almost 90 years (Snelgrove, 1935) but little work has been accomplished since 1935. The Rose Blanche area is comprised of the Grandy’s Formation, a Middle Ordovician mica-garnet schist and interbedded carbonaceous slates and quartzites (White, 2008). This study is looking at the Rose Blanche locality to determine if the quartz pod truly formed under conditions appropriate for gold formation, and then compare those results to other similar deposits throughout Newfoundland and beyond. To accomplish this, fluid inclusions found within quartz samples were examined using petrographic and microanalytical geochemical techniques. The analysis of quartz fluid inclusion assemblages provided insight to the temperature and pressure conditions at which the inclusions were formed, giving clues about the nature of quartz and gold formation. This quartz pod can provide better evidence of a potential pre-existing or existing mesothermal gold deposit. Fluid inclusion analysis will help determine the type of mesothermal deposit present at Diamond Cove, and whether it is orogenic or related to the Rose Blanche intrusion. The samples collected at Rose Blanche range from massive bull quartz to terminated quartz crystals in pockets within the interlayered schist hosted rock. The primary mineralogy consists of quartz, but crystals of arsenopyrite and pyrite are visible as well. Microthermometry of the fluid inclusions will be done using a heating-freezing fluid inclusion stage. This will provide the minimum temperature and pressure of trapping, the bulk composition for samples, and will identify the dominant fluids during crystallization.

Geological Society of America Abstracts with Programs. Vol. 49, No. 2

doi: 10.1130/abs/2017NE-290900

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