Ore-microscopic and geochemical characteristics of gold-tellurides-sulfide mineralization in the Macassa Gold Mine, Abitibi Belt, Canada

Abstract

The Macassa Gold Mine is the only operational mine (Lac-Minerals Ltd., Macassa Division) of seven original gold producers in the Kirkland Lake camp of northern Ontario, Canada. The gold deposit is in Archaean volcanic and sedimentary rocks which have been intruded by a composite syenite stock. The mineralization has taken place in two stages. The first stage is not gold bearing but involves pyritization and concomitant development of titanium phase minerals (leucoxene, rutile) and hematite. It is mainly associated with carbonatization, silicification and hematitization marked by Ba, Sr and Rb enrichment. In contrast to this, the quartz vein-type mineralization is associated mainly with later silicification and enrichment with tellurium, lead, silver, gold and copper. It is relatively depleted in Sr, Ba and Rb. The ore mineralogical assemblages in the second stage include pyrite, chalcopyrite, petzite, altaite and native gold. Geochemical and petrographic evidence indicate that the reddened wall rocks (hematitized) and reddened fragments are neither related with nor contain any gold. Therefore, hematitization and the presence of barium, in this case in K-feldspars, could not be considered as the sole evidence to suggest a magmatic oxidizing fluid model for the genesis of Macassa gold deposit. Regarding the metals transport, tellurides and thiocomplexes are considered as the important carriers of gold and silver. Hence, fugacity of tellurium and sulphur controlled the precipitation of gold in the Macassa gold deposit.The worldwide acceleration of exploration activities for gold accompanying its rise in price has led to increased interest in the understanding of its genesis, mainly on the Archaean vein-type gold deposits. Consequently, various models have been proposed by different geoscientists conforming with the basic postulates: high Au: Ag ratio, low base metals, low salinity, high temperature and structural setting in stabilized cratons (greenstone belts). However, when it comes to a type area, different models are proposed by different researchers. One of the best examples is the Macassa gold deposit.For instance, Ridler (1970) postulated a syngenetic metamorphic origin for the gold deposits of Kirkland Lake-Larder Lake including Macassa. According to the author, the gold was mainly derived from the banded iron-formations where it was originally present as an "exhalite" mineralization of extremely low grade. Kerrich and Watson (1984) studied the heavy oxygen isotope of quartz from the wall rocks and veins in the Macassa gold deposit and suggested a metamorphic model indicating the origin of the fluid to be largely metamorphic dehydration under conditions of moderate Eh and weak acidity. Hinse et al. (1986) proposed a general theory of genesis for the Archaean vein-type mineralizations using the Kirkland Lake -Larder Lake break of northern Ontario and Quebec as a model. They suggested that gold and associated constituents derived as weathering products from mafic-ultramafic volcanics and were concentrated as s...

Ore‐forming physicochemical conditions of tellurium–gold deposits: A case study from the Guilaizhuang deposit, eastern North China

“…Fluorite, halite, and kerargyrite were found in the deposit, which indicate that the hydrothermal fluid in this deposit has a higher Cl − . This condition is similar to the Canadian Macassa tellurium–gold deposit, the western United States Gripple Creek tellurium–gold deposit, Fiji's Emperor tellurium–gold deposit, and Dongping gold deposit, among other examples (Thompson et al, ; Ahmad et al, ; Tesfaye, ; Cook et al, ). Hence, we speculate that the Au at this stage mainly migrated as AuCl 2 − and Au(HS) 2 − complexes.…”

“…Tellurium–gold deposits over the world have attracted considerable interest with regard to their characteristics and genesis, and several investigations have been carried out on these in the last few decades (Thompson, Trippel, & Dwelley, ; Ahmad, Solomon, & Walshe, ; Bortnikov, Kramer, Genkin, Krapiva, & Cruz, ; Tesfaye, ; Spry, Paredes, Foster, Truckle, & Chadwick, ; Spry, Foster, Truckle, & Chadwick, ; Spry & Thieben, ; Zhang & Mao, ; Niu, Li, & Sun, ; Mo, Wang, & Cheng, ; Zhang, ; Zhang & Li, ; Wang & Zhang, ; Qi & Li, ; Wang, Niu, Sun, & Li, , ; Mao, Li, Goldfarb, He, & Zaw, ; Hu, ; Li & Santosh, , ; L. Li, Santosh, & Li, ; L. Li et al, ; L. Li, Li, Santosh, Zhu, & Suo, .). The typical difference between tellurium–gold deposits and normal gold deposits is the significant content of tellurium–gold minerals, or even native tellurium, in the former.…”

“…Tellurium-gold deposits over the world have attracted considerable interest with regard to their characteristics and genesis, and several investigations have been carried out on these in the last few decades (Thompson, Trippel, & Dwelley, 1985;Ahmad, Solomon, & Walshe, 1987;Bortnikov, Kramer, Genkin, Krapiva, & Cruz, 1988;Tesfaye, 1992;Spry, Paredes, Foster, Truckle, & Chadwick, 1996;Spry, Foster, Truckle, & Chadwick, 1997;Spry & Thieben, 1999;Zhang & Mao, 1995;Niu, Li, & Sun, 1996;Mo, Wang, & Cheng, 1996;Zhang, 1996;Zhang & Li, 1997;Wang & Zhang, 1991;Qi & Li, 2000;Wang, Niu, Sun, & Li, 2003a, 2003bMao, Li, Goldfarb, He, & Zaw, 2003; tion stages and evaluate the physicochemical conditions of hydrothermal fluids through the application of fluid inclusion studies, estimation of pressure, density, salinity, pH, Eh, sulfur fugacity, and tellurium fugacity. Our study provides insights into the pattern of occurrence of gold and its migration and precipitation mechanism.…”

Caractéristiques, chronologie et typologie des minéralisations aurifères de la région du Lac Shortt (Québec), sous-province archéenne de l'Abitibi /

“…Les arguments apportés ont toutefois été discutés (Kerrich 1991;Tesfaye 1992). Barron (1991) a aussi montré que les carbonatites archéennes de la Province de Supérieur ne sont pas particulièrement enrichies en or; par conséquent, elles ne constitueraient pas une source très probable pour l'or.…”

Fluid Inclusion and Noble Gas Studies of the Dongping Gold Deposit, HebeiProvince, China: A Mantle Connection for Mineralization?

“…Bonham (1986) proposed that telluride-rich gold deposits are essentially epithermal deposits. Some gold-bearing telluride epithermal deposits, such as Cripple Creek, Colorado (Thompson et al, 1985;Bonham, 1986), Emperor, Fiji (Ahmad et al, 1987), Macassa, Abitibi belt, Canada (Tsefaye, 1992), and Golden Sunlight, Montana (Spry et al, 1996), are genetically related to alkaline complexes; others, such as the Major's Creek deposit, Australia (Wake and Taylor, 1988) and some deposits in the Kuril island arc, Russia (So et al, 1995), are related to shallow granites and their associated volcanism. Fluid inclusion temperature and pressure estimates at Dongping are not, however, typical of ore deposits formed in an epithermal environment.…”