Ore Genesis of the Takatori Tungsten–Quartz Vein Deposit, Japan: Chemical and Isotopic Evidence

Abstract

The Takatori hypothermal tin–tungsten vein deposit is composed of wolframite-bearing quartz veins with minor cassiterite, chalcopyrite, pyrite, and lithium-bearing muscovite and sericite. Several wolframite rims show replacement textures, which are assumed to form by iron replacement with manganese postdating the wolframite precipitation. Lithium isotope ratios (δ7Li) of Li-bearing muscovite from the Takatori veins range from −3.1‰ to −2.1‰, and such Li-bearing muscovites are proven to occur at the early stage of mineralization. Fine-grained sericite with lower Li content shows relatively higher δ7Li values, and might have precipitated after the main ore forming event. The maximum oxygen isotope equilibrium temperature of quartz–muscovite pairs is 460 °C, and it is inferred that the fluids might be in equilibrium with ilmenite series granitic rocks. Oxygen isotope ratios (δ18O) of the Takatori ore-forming fluid range from +10‰ to +8‰. The δ18O values of the fluid decreased with decreasing temperature probably because the fluid was mixed with surrounding pore water and meteoric water. The formation pressure for the Takatori deposit is calculated to be 160 MPa on the basis of the difference between the pressure-independent oxygen isotope equilibrium temperature and pressure-dependent homogenization fluid inclusions temperature. The ore-formation depth is calculated to be around 6 km. These lines of evidence suggest that a granitic magma beneath the deposit played a crucial role in the Takatori deposit formation.

Role of Hydrothermal Fluids in the Formation of the Kamioka Skarn-Type Pb–Zn Deposits, Japan

“…This is inconsistent with a magmatic origin, suggesting instead a shear-zone induced hydrothermal system with meteoric water [22]. Even if there was early-stage magmatic fluid for the Takatori hypothermal tungsten-quartz vein deposit in Japan, the δ 18 O value of the fluid decreased with decreasing temperature because the fluid was mixed with meteoric water [23].…”

Hydrothermal Calcite Precipitation in Veins: Inspired by Experiments for Oxygen Isotope Fractionation between CO2 and Calcite from 1 °C to 150 °C

“…The relationships between equilibrium and kinetics from the previous oxygen isotopic studies on hydrothermal ore deposits are discussed in the second half. Several isotopic studies (Kushikino deposit [22,29], Ohtani and Kaneuchi deposits [24], Takatori deposit [25], and Noya deposit [26]) were introduced, assuming that the mineral assemblages were close to equilibrium. We observed varying degrees of kinetic reactions and equilibrium goals in the δ 13 C-δ 18 O relationship of limestone at the Kamioka deposit [27].…”

“…The following estimations of the oxygen isotope equilibrium temperatures of the mineral-pair formation were used as an oxygen isotope thermometer based on the isotopic equilibrium for the mineral-pair: a quartz-muscovite thermometer for tungstenquartz vein deposits (Ohtani and Kaneuchi deposits [24]), quartz-wolframite and quartzcassiterite thermometers for tungsten-quartz vein deposits (Takatori deposit [25]), and a quartz-calcite thermometer for gold-bearing quartz-calcite veins (Noya deposit [26]).…”

Fluid Evolution of Greisens from Krupka Sn-W Ore District, Bohemian Massif (Czech Republic)

“…The δD fluid values for samples KR-4 and KR-5 are very similar to the δD values of altered granites from the Bohemian Massif (Figure 17). Based on oxygen isotopes, the participation of both magmatic and meteoric fluids during the formation of quartz veins with Sn-W mineralization was also reported [69] from the Takatori deposit in Japan. [68], granites from Horní Slavkov-Hub Stock [17] and Cínovec [14], greisens from Iberian Central system [70], greisen cassiterite mineralization from Uljin Area [71], greisens from New Ross area in Canada [72], Sn-W mineralization, Mawchi, Myanmar [73], and unpublished data by M. René for topaz-albite granites of the Bohemian Massif.…”