The Akagane mine is one of the important iron and copper deposits of Japan, mainly of contact metasomatic origin.
In this study, the igneous rock with which the Akagane ore deposits is connected, is discussed from the paleomagnetic point of view.
The natural remanent magnetization of the ore and of the igneous rocks around this deposits were measured. The direction of remanent magnetization of the ore and igneous rocks are as follows:
ore 17°W 64°D
gabbro 63°W 63°D
quartz diorite 57°W 66°D
quartz porphyry 35°W 68°D
granite porphyry 18°W 66°D.
According to A. C. demagnetization tests, measurements of the magnetic susceptibility, microprobe analysis and others, the direction of the remanent magnetization of the ore and igneous rocks apeared to be in accordance with that of the geomagnetic field at each mineralization or intrusion period. It is concluded that the direction of the geomagnetic field was in the time of ore deposition very similar to that of the granite porphyry intrusion, but different from the time of intrusion of other igneous rocks, because the geomagnetic dipole was moving gradually in the course of geological time.
Then, it is suggested that the granite porphyry is the igneous rock with which the ore is genetically related.
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