Oxygen-isotope geochemistry of metamorphosed, massive sulfide deposits of the Flin Flon ? Snow Lake belt, Manitoba

Copper Isotope Characteristics of Copper-Rich Minerals From Besshi-Type Volcanogenic Massive Sulfide Deposits, Japan, Determined Using a Femtosecond La-Mc-Icp-MS

“…Kajiwara and Date (1971) measured sulfur isotopes of sulfide minerals from several Besshitype deposits in Japan and suggested that the original sulfur isotope characteristics in these deposits have not changed remarkably during regional metamorphism, though sulfur isotope homogenization and reequilibration may have taken place. Similar features were also observed in metamorphosed VMS deposits worldwide, where regional metamorphism did not lead to an extensive degree of homogenization; large-scale (individual deposit or ore field), premetamorphic sulfur and oxygen isotope characteristics were generally preserved, however, small-scale (hand specimen or grain to grain) isotopic homogenization occurred and therefore reduced the original isotopic range (e.g., Aggarwal and Longstaffe, 1987;Skauli et al, 1992;Cook and Hoefs, 1997). According to the compilation of sulfur isotope data of sulfide minerals (chalcopyrite, pyrite, and pyrrhotite) from many Besshi-type deposits in Japan by Sato and Kase (1996), the δ 34 S values of sulfide minerals from the major Besshi-type deposit in the Sanbagawa metamorphic belt are distributed between 0 and 5 per mil, without significant variation in a single deposit, and are nearly identical to those from the sediment-barren ridges, while the δ 34 S values for the major Besshi-type deposit in the Shimanto belt are shown from 5 to 10 per mil, which are similar to those from the sediment-covered ridges such as the Middle Valley at the northern end of the Juan de Fuca Ridge.…”

Geology and Geochemistry of Highly Metamorphosed Footwall Alteration Zones in the Hongtoushan Volcanogenic Massive Sulfide Deposit, Liaoning Province, China

“…Such a variation indicates that extensive isotope homogenization (Aggarwal & Longstaffe, 1987; Kempton & Harmon, 1992) has not occurred, and hence pervasive fluid flow was absent during metamorphism in the Hongtoushan area. Isotopic exchange between minerals under fluid‐absent circumstance generally occurs on a grain‐to‐grain scale, over no more than a few meters (Aggarwal & Longstaffe, 1987). Furthermore, no evidence has been found for pervasive retrograde alteration in both CAGs.…”

“…Inter‐mineral and mineral/fluid oxygen isotope exchange could occur during metamorphism (Aggarwal & Longstaffe, 1987; Zheng et al ., 2001), especially when external fluid is present (Valley & O'Neil, 1982; Valley, 1986; Zheng et al ., 2001). As shown in Table 2 and Figure 16, an extremely large δ 18 O variation up to about 5‰ from 2.7 to 7.1‰ is detected in CAG.…”

“…As shown in Table 2 and Figure 16, an extremely large δ 18 O variation up to about 5‰ from 2.7 to 7.1‰ is detected in CAG. Such a variation indicates that extensive isotope homogenization (Aggarwal & Longstaffe, 1987; Kempton & Harmon, 1992) has not occurred, and hence pervasive fluid flow was absent during metamorphism in the Hongtoushan area. Isotopic exchange between minerals under fluid‐absent circumstance generally occurs on a grain‐to‐grain scale, over no more than a few meters (Aggarwal & Longstaffe, 1987).…”

Stable isotopic constraints on Kuroko-type paleohydrothermal systems in the Mesoproterozoic Serra do Itaberaba group, São Paulo State, Brazil

“…Aggarwal and Longstaffe (1987) interpret differences in the oxygen isotope compositions of altered host rocks of metamorphosed massive sulfide deposits in the Flin Flon-Snow Lake belt (Canada) as produced before metamorphism, during hydrothermal alteration related to ore deposition. Preservation of hydrothermal oxygen isotope signatures in Precambrian massive sulfide deposits was observed by Beaty et al (1988); Beaty and Taylor (1982), and Araújo et al (1996), in which cases dehydration reactions did not significantly affect d 18 O values.…”