Hinako Sato

Triassic Epithermal Au and Porphyry Related Cu-Mo Mineralization of the Chatree Deposit, Central Thailand

The Chatree mining area is located in the LoeiPhetchabun-NakhonNayok volcanic belt, about 300 km north of Bangkok in Thailand. The Chatree deposit consists of five defined prospects and five open pits. The A and Q prospects (Au mineralization) are located in the northern part of the Chatree deposit. The C, H, D, Kw and Ke pits (Au mineralization) are distributed in the central part of the deposit. The B (Au mineralization), N and V (Cu-Mo mineralization) prospects occur in the southern part of the deposit. Ore bodies studied are the Q, A, B, N and V prospects. Geology of the Chatree deposit consists of andesite lava, monomictic andesitic breccia, polymictic andesitic breccia, volcanic sedimentary breccia and fiamme breccia. Andesite dikes cut these strata and ore bodies. Au mineralization (250±0.8 Ma, Salam et al., 2008) is developed in polymictic andesitic breccia and volcanic sedimentary breccia strata. Granodiorite occurs at the N and V prospects approximately 2 km far from the Q prospect. The granodiorite (243±5 Ma, Salam et al., 2008) intruded into andesite lava. Cu-Mo mineralization is recognized in the granodiorite (N and V prospects). The age of mineralization of the Chatree deposit is Early Triassic. The aim of study is to elucidate the styles of gold and copper mineralization and to estimate the source of gold in the Chatree deposit.

Characteristic Features of Ra‐Pb‐Sr‐Rare Metal‐bearing Tamagawa Acidic Thermal Water Derived from a Deep‐seated Magmatic System in Akita Prefecture, Japan

Ohbuki hot spring in the Tamagawa hot spring area, which is associated with volcanic activity, is a famous hot spring characterized by strong acidity and presence of radium. Many studies on the thermal water of Ohbuki hot spring have been carried out. Iwasaki et al. (1963) reported that the anions in thermal water of Ohbuki hot spring are transported by volcanic gas derived from active magma, while Yoshiike (1996) proposed that the cations in the thermal water are derived from volcanic rocks in the shallow underground part around Tamagawa. We examined the chemical characteristics of thermal water on the basis of concentrations of major and trace elements and Sr, Nd and Pb isotopic ratios of the thermal water and estimated the source of elements in the thermal water.