@article{oai:ir.kagoshima-u.ac.jp:00000892,
 author = {井沢, 英二 and 浦島, 幸世},
 journal = {南方海域調査研究報告=Occasional Papers},
 month = {2016-10-27},
 note = {An active high temperature geothermal system consists typically of a magmatic heat
source, water to tramsport the heat, and fractures or permeable zones where the water
flows. When the heat source cools down and the geothermal system becomes inactive,
we call this a paleo-geothermal system or fossil geothermal system.
Gold is often transported by ascending waters in the high temperature geothermal
system related with volcanic activities. The upper level of the system, at a depth of
around 400m or less, is a favorable site of gold deposition. Therefore, epithermal gold
deposits and their environments correspond to the paleogeothermal systems, of which
high level portions are often eroded away.
There are many active- and paleo-geothermal systems in island-arc settings of the
western Pacific rim and adjacent regions. Representative gold deposits are: Taio,
Kushikino, Hishikari and Iwato in Kyushu, Japan; Chinkuashih in Taiwan; Acupan-
Antamok in the Philippines; Lebong Donok and Lebong Tandai in Sumatra, Indonesia;
Wau in Papua New Guinea; Mavu in the Solomon Islands; Vatukoula and Mt.Kasi in
Fiji; and Waihi in New Zealand.
These late Cenozoic epithermal gold regions have several characteristics. (1) Volcanic
activities started less than 15-16 million years ago and continued to the late Quaternary.
(2) Igneous rocks related to the gold mineralization are predominantly dacite or hornblende andesite of the calc-alkalic series. Volcanic rocks of the alkalic series, however, host
some of the gold deposits. (3) The site of the gold deposits are restricted to within 8km (usually 4km) of the center of volcanic activity. (4) Two types of gold deposits are
recognized, the quartz-adularia veins usually with Mn-carbonates, and those in massive silicified rocks.
Basements consist of a thick sedimentary sequence in the case of Kyushu, Japan and
New Zealand; and probably of oceanic crust in the case of Fiji. Porphyry copper deposits occur intimately with gold deposits in the Philippines and Papua New Guinea
but not in Kyushu.},
 pages = {71--86},
 title = {南方島弧の古地熱系},
 volume = {11},
 year = {}
}