1991 Fiscal Year Final Research Report Summary
Study on Formation Mechanism of Skarn-type Mineral Deposits
| Project/Area Number |
01303006
|
|---|
| Research Category |
Grant-in-Aid for Co-operative Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
鉱物学(含岩石・鉱床学)
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
SHIMAZAKI Hidehiko Univ. Tokyo, Faculty of Sci., Professor, 理学部, 教授 (50013751)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MATSUEDA Hiroharu Hokkaido Univ., Faculty of Sci., Assoc. Prof., 理学部, 助教授 (20108921)
UCHIDA Etsuo Waseda Univ., Faculty of Sci. & Eng., Assist. Prof., 理工学部, 助手 (40185020)
NAKANO Takanori Tsukuba Univ., Insti Geosci., Assist. Prof., 地球科学系, 助手 (20155782)
KANEDA Hiroaki Univ. Tokyo, Faculty of Eng., Assist. Prof., 工学部, 助手 (10092181)
SHIKAZONO Naotasu Keio Univ., Faculty of Sci. & Eng., Assoc. Prof., 理工学部, 助教授 (10011751)
|
|---|
| Project Period (FY) |
1989 – 1991
|
| Keywords | Skarn Deposits / Mineralization / Mineralizing Solution / Light Stable Isotopes / Meteoric Water-Circulating Hydrothermal System / Fluid Inclusion / Compositional Variation / 組成変動 |
|---|
| Research Abstract |
Through three years research, many results were obtained. Only main results are given as follows :
1. Mineral Analysis Group : Compositional variations of main skarn minerals such as clinopyroxene and epidote, in a crystal grain, in a hand-specimen, and in an orebody, fall in almost same ranges. Balance between infiltration and diffusion, and local variation as well, of components transported by hydrothermal solutions, cause such compositional variations of skarn minerals.
2. Fluid Inclusion Analysis Group : Formation temperatures of skarns have generally very wide ranges such as 500ﾟ to 200ﾟC. Salinity of the fluids is very variable. The presence of CO_2 and CH_4 gases is recognizable. In most cases, skarn minerals include many primary inclusions, and hydrogen isotope analysis technique is applicable to those minerals.
3. Light Stable Isotope and REE Analysis Group : Oxygen isotope data of Japanese main skarn deposits are accumulated, and it was clarified that most of large-production deposits are formed by hydrothermal solutions of meteoric origin. The Tsumo skarn deposits were formed by the solutions of very complicated origins. REE patterns of skarn minerals are much affected by the physico-chemical conditions of solutions, oxygen fugacities in particular, of the mineral-precipitating solutions.
4. Regional Geology Correlation Analysis Group : Minor tungsten mineralizations are observed in many Japanese skarn deposits, overlapping with the Fe-Cu-Zn-Pb mineralizations. They have common characteristics in mineralogy and geology.
|
