A Systematic Study of Rare Earth and Trace Element Geochemistry of Host Rocks to the Kidd Creek Volcanogenic Massive Sulfide Deposit
Published:January 01, 1999
Eva S. Schandl, Michael P. Gorton, Wouter Bleeker, 1999. "A Systematic Study of Rare Earth and Trace Element Geochemistry of Host Rocks to the Kidd Creek Volcanogenic Massive Sulfide Deposit", The Giant Kidd Creek Volcanogenic Massive Sulfide Deposit, Western Abitibi Subprovince, Canada, Mark D. Hannington, C. Tucker Barrie
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Altered rhyolites that host the Archean Kidd Creek volcanogenic massive sulfide deposit have constant Hf-Th-Ta ratios throughout the entire deposit. Such constant ratios suggest that footwall and immediate hanging-wall rhyolites represent a single batch of high silica rhyolitic magma and that fractionation of accessory minerals was suppressed during crystallization.
Although extensive alteration has destroyed most primary minerals in the rhyolites and disturbed their geochemistry, high field strength elements such as Th, Ta, and Hf remained immobile during alteration and may be used to identify the protoliths and to determine the original trace element geochemistry of even the most altered rocks. Quantitative estimation of rare earth element (REE) mobility in the rhyo-lites demonstrates significant mobility, particularly in the highly altered stringer zone, in the bornite zone, and in the southernmost part of the deposit in rhyolite fragmentals. Nearly quantitative removal of light REE occurred in highly silicified rhyolite immediately underneath the massive sulfides. Furthermore, REE mobility was identified up to a distance of 2 km from the deposit.
Mafic rocks at Kidd Creek, excluding footwall komatiite flows and plagioclase porphyritic pillow basalts in the uppermost hanging wall, can be separated into four groups. This classification is consistent with stratigraphic position and general field appearances of the mafic rocks. Group I consists of primitive low TiO2 basaltic flows in the footwall of the distal Kidd Creek horizon and is characterized by concave-upward chondrite-normalized REE patterns. Group II consists of relatively low TiO2 pillow basalts and associated gabbro sills in the immediate hanging wall. This group includes the “spotted gabbro sills” at the mine and is characterized by midocean ridge basaltlike, slightly light REE-depleted patterns. Group III consists of high TiO2 gabbro sills that intrude both the hanging wall and footwall of the deposit and have slightly light REE-enriched patterns. Group IV represents more evolved gabbro to diorite sills and could be related to group III. The groups have distinct and relatively undisturbed REE patterns. The REE sys-tematics and incompatible element ratios such as Th/Yb versus Ta/Yb indicate that groups I, II, and III are unlikely to be related by fractional crystallization. Different parental magmas are implicated.
Figures & Tables
The Giant Kidd Creek Volcanogenic Massive Sulfide Deposit, Western Abitibi Subprovince, Canada
ARCHEAN Cu-Zn deposits are among the most important mineral deposit types in Canada. The Superior province of Canada contains nearly 80 percent of the known Archean Cu-Zn deposits in the world (about 100 of 125 deposits). These deposits are concentrated in 10 separate mining camps, including Sturgeon Lake, Manitouwadge, Mattagami Lake, Chibougamau, Joutel, Val d’Or, Bous-quet, Noranda, Kidd Creek, and Kamiskotia (Fig. 1 and Table 1). A few deposits in rocks of similar age and composition are also known in the Slave province, the Churchill province, and in the Archean of Western Australia, southern Africa, China, and Brazil. Known deposits of this age worldwide account for more than 650 million metric tons (Mt) of massive sulfides, containing 10 Mt of Cu metal, 29 Mt of Zn, 1 Mt of Pb, 33 Mkg Ag, and 750,000 kg Au. The giant Kidd Creek volcanogenic massive sulfide deposit in the western Abitibi subprovince of Canada is the largest known deposit of this age currently in production. The Superior province is the world’s largest exposed Archean craton, occupying an area of more than 1.5 million km2, bounded by the Trans-Hudson orogen to the west and the Grenville province to the east. A number of distinct subprovinces are recognized, assembled into east-west-trending granite-greenstone terranes and metasedi-mentary belts (Fig. 1). The granite-greenstone terranes are composed of gneissic rocks of plutonic origin, supracrustal rocks of dominantly volcanic origin, and a variety of syn- to late kinematic granitoids. Volcanic rocks comprise about 12 percent of the total area. The greenstone belts have been described variously as successive lateral accretions of volcano-plutonic arcs, oceanic islands, oceanic plateaus, and rift-related assemblages (e.g., Langford and Morin, 1976; Percival and Card, 1985; Ludden and Hubert, 1986; Ludden et al., 1986; Card, 1990; Jackson and Sutcliffe, 1990; Williams, 1990; Corfu, 1993; Heather et al., 1995; Jackson and Cruden, 1995). The metallogenic history of the Superior province has been described in detail by Franklin and Thorpe (1982) and Poulsen et al. (1992).
The Abitibi subprovince (94,000 km2) is the largest of the greenstone belts. It contains the major gold and base metal mining camps in Canada (Fig. 2), with production and reserves totaling more than 480 Mt of massive sulfide and 4,700 t of Au. Metal production in the western portion of the Abitibi greenstone belt is dominated by the Timmins region, which historically has accounted for 37 percent of the total gold production