Limonite Deposits of the Kamikita Mine, Aomori Prefecture

Abstract

The ore deposits of the Kamikita Mine are composed of several massive and layered replacement bodies of black-ore type in a breecia zone in liparite and liparitic tuff which are related to Miocene volcanic activity.
Two types of limonite deposits are found near the copper and pyrite deposit of Okunosawa. One type may be regarded as oxidation of the black-ore; the other limonite may be secondarily precipitated from ground grater passing through the black-ore deposits.
Barite, diaspore and iron-sulphide occur in the limonite deposits of the oxidized type; they are not found in the precipitated limonite beds.
The results of spectroscopic analysis show the following:
(1) Metallic elements such as Ag, Ba, Bi, Cu, Ge, Mo, Mn, Na, Pb, Pt, Sb, Si, Sn, Ti, Zn, etc., are contained in the precipitated limonite bed of the Kamikita Mine.
(2) Metallic elements as Mo, Pb, etc. are contained in the precipitated limonite bed of the Kami-kita Mine, but are not found in limonite beds in Japan which have formed from ferruginous springs that are related to neo-volcanic activity.
From these observations, it seems likely that some metallic minor elements indicate the genesis of the "limonite".