TY - JOUR
T1 - The Kago low-sulfidation gold and silver deposit
T2 - A peripheral mineralisation to the Nansatsu high-sulfidation system, southern Kyushu, Japan
AU - Tindell, Thomas
AU - Watanabe, Koichiro
AU - Imai, Akira
AU - Takahashi, Ryohei
AU - Boyce, Adrian J.
AU - Yonezu, Kotaro
AU - Schersten, Anders
AU - Page, Laurence
AU - Ogata, Takeyuki
N1 - Funding Information:
We would like to express our sincere thanks to Eiji Izawa for his constant advise and expertise in this study. Additionally we are indebted to Masamichi Yamashita for donation of samples and Alison MacDonald at the Scottish Universities Environmental Research Centre for assistance with isotopic analysis. This study was supported by a Grant in-aid from the Global Center of Excellence in Novel Carbon Resource Science.
Funding Information:
We would like to express our sincere thanks to Eiji Izawa for his constant advise and expertise in this study. Additionally we are indebted to Masamichi Yamashita for donation of samples and Alison MacDonald at the Scottish Universities Environmental Research Centre for assistance with isotopic analysis. This study was supported by a Grant in-aid from the Global Center of Excellence in Novel Carbon Resource Science.
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2018/11
Y1 - 2018/11
N2 - The Kago deposit is a small deposit located at the southern tip of the Satsuma Peninsula of Southern Kyushu, Japan. It lies proximal to the well-known Nansatsu-type mineralisation province dominated by high-sulfidation type epithermal deposits. The deposit was heavily mined in the 18 th Century, largely for its relatively higher gold compared to that of surrounding and regional deposits. The Kago deposit is a typical low-sulfidation deposit, characterised by adularia-quartz veins, composed of electrum, Ag-tetrahedrite, polybasite, chalcopyrite and pyrite. Based on mine records, the grade ranged from 4.1 to 13.3 g/t Au and 2.6–6.6 g/t Ag. Alteration grades from low to high temperature argillic into a propylitic zone at the extremes of the vein exposures. Carbonate is absent. Fluid inclusion microthermometry reveals a typical temperature range of 220–240 °C with salinity of 0.7–2.6 NaCl eq. wt%. Electrum from high-grade ore ranges from 66 to 69 wt% Au. 40Ar/39Ar age dating of adularia bearing colloform/crustiform and brecciated veins, suggests a mineralisation event from 4.23 to 4.0 Ma. δ18O of veined and silicified quartz ranges from +4.0 to +18.4‰. δ18OH2O of fluids in equilibrium with quartz, in the dominant range of measured fluid inclusion temperatures, ranges from −6.5‰ to −0.2‰. δ34S of pyrite has a narrow range from −1.8 to 2.7‰. The deposit lies at the northern extent of the classic Nansatsu high-sulfidation epithermal area, in which a number of silicified bodies punctuate the region in a roughly semi-circular shape. The Kago deposit lies within the principle mineralisation age range of the high-sulfidation deposits, which range from 5.5 to 3.7 Ma. The structural displacement of the Kago deposit from the Nansatsu mineralisation and the differing host rocks has greatly influenced alteration, ore and rock-water interaction of the ore depositing fluids. Here we seek to establish the relationship that this extended mineral province has between the differing styles of mineralisation.
AB - The Kago deposit is a small deposit located at the southern tip of the Satsuma Peninsula of Southern Kyushu, Japan. It lies proximal to the well-known Nansatsu-type mineralisation province dominated by high-sulfidation type epithermal deposits. The deposit was heavily mined in the 18 th Century, largely for its relatively higher gold compared to that of surrounding and regional deposits. The Kago deposit is a typical low-sulfidation deposit, characterised by adularia-quartz veins, composed of electrum, Ag-tetrahedrite, polybasite, chalcopyrite and pyrite. Based on mine records, the grade ranged from 4.1 to 13.3 g/t Au and 2.6–6.6 g/t Ag. Alteration grades from low to high temperature argillic into a propylitic zone at the extremes of the vein exposures. Carbonate is absent. Fluid inclusion microthermometry reveals a typical temperature range of 220–240 °C with salinity of 0.7–2.6 NaCl eq. wt%. Electrum from high-grade ore ranges from 66 to 69 wt% Au. 40Ar/39Ar age dating of adularia bearing colloform/crustiform and brecciated veins, suggests a mineralisation event from 4.23 to 4.0 Ma. δ18O of veined and silicified quartz ranges from +4.0 to +18.4‰. δ18OH2O of fluids in equilibrium with quartz, in the dominant range of measured fluid inclusion temperatures, ranges from −6.5‰ to −0.2‰. δ34S of pyrite has a narrow range from −1.8 to 2.7‰. The deposit lies at the northern extent of the classic Nansatsu high-sulfidation epithermal area, in which a number of silicified bodies punctuate the region in a roughly semi-circular shape. The Kago deposit lies within the principle mineralisation age range of the high-sulfidation deposits, which range from 5.5 to 3.7 Ma. The structural displacement of the Kago deposit from the Nansatsu mineralisation and the differing host rocks has greatly influenced alteration, ore and rock-water interaction of the ore depositing fluids. Here we seek to establish the relationship that this extended mineral province has between the differing styles of mineralisation.
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U2 - 10.1016/j.oregeorev.2017.10.027
DO - 10.1016/j.oregeorev.2017.10.027
M3 - Article
AN - SCOPUS:85034964309
SN - 0169-1368
VL - 102
SP - 951
EP - 966
JO - Ore Geology Reviews
JF - Ore Geology Reviews
ER -