1997 Fiscal Year Final Research Report Summary
Comparative study of mineral textures in Kuroko and Sea-floor hydrothermal ore deposit
| Project/Area Number |
04640726
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
鉱物学(含岩石・鉱床学)
|
|---|
| Research Institution | Hokkaido University |
|---|
Principal Investigator |
MATSUEDA Hiroharu Hokkaido Univ., Grad.Sch.of Sci., Assoc.Prof., 大学院理学研究科, 助教授 (20108921)
|
|---|
| Project Period (FY) |
1992 – 1993
|
| Keywords | kuroko deposits / sea-floor hydrothermal deposits / mineral texture / crystal growth / sphalerite / chemical composition / spatial distribution / diagenesis |
|---|
| Research Abstract |
The purpose of this study is to clarify the genesis of massive sulfide deposits such as Kuroko and sea-floor hydrothermal ore deposits based on the comparative study of the mineral texture. Special attentions are paid for the relationships between mineral texture and chemical compositions of sphalerite and their spatial distributions according to the microscopic observation and systematic classification of mineral textures. It has been clarified the distinct intimate relationships between both. 3-types of Kuroko ore are distinguished for the Upper black ore deposits of Matsumine mine in Akita Prefecture and their spatial distributions might be controlled by the diagenetic processes after the formation. On the other hands, detailed underground observations and systematic sampling have been done for the black ore in the satellite ore body of Kanayamazawa East, Fukazawa mine. The ore is classified into 6-types and their distributions is clarified in the ore bodey, where black ore formed on the unstable slope might be distructed and/or slided to be removed and resedimentated. Matrix-filling by chalcedonic quartz and chalcopyrite diseased textures are universally observed under the microscope. They might be caused by the continued circulation of hydrothermal water after the main ore formation. To make comparison with sea-floor hydrothermal ore deposits, microscopic observations have been made for the specimen collected from East Pacfic Rise (EPR) 13ﾟ N.There are some similarities and differences between both and the latter could be depend on the epigenetic process such as diagenesis.
|
