The Variation of Mn and Fe Contents in the Wall Rocks of the Misago Ore Body, Nodatamagawa Mine, Iwate Prefecture, Japan

Abstract

The genesis of the bedded manganese deposits has been discussed by many geologists with the different view-points. The writer intends to know the change of Mn and Fe contents in the wall rocks of this type of ore deposits and its relation with the genesis.
The study was carried out at the Misago ore body of the Noda-Tamagawa manganese Mine, Iwate Prefecture. Semi-quantitative analyses of Mn and Fe contents in the wall rocks were made by the X-ray fluorescence method. The two elements, Mn and Fe, are variously contained in the wall rocks and the difference between the concentration of these two elements in the hanging wall and foot wall is considered to be related to the different environments of sedimentation of the wall rocks. Also it is found a Mn-poor zone existed in the wall rocks near the ore body.
The Mn and Fe contents of the wall rocks as an indicator for ore prospecting are only effective within the distance of a few meters from ore bodies.