The bedded manganese and manganiferous iron deposits in this area are distinctly strata-bound. The manganese deposits are concentrated in a lower Permian formation of the North Kitakami belt and in a middle Jurassic formation of the Iwaizumi belt, while the manganiferous iron deposits are in a Paleozoic formation of the Hayachine belt. The manganese deposits occur abundantly in the alternation zone of slate and chert, but rarely in chert dominant zone, implying that the depositional environment of these deposits may have been a moderately deep sea-floor of eugeosynclinal basin. The deposits are conformable to the wall rocks rich in banded chert, and large-scale deposits are often underlain by massive chert which is thought to have been a product of hydrothermal activity. The manganiferous iron deposits, whose occurrence is limited to schalstein zone, are also conformable to the wall rocks which comprise mostly banded and massive cherts. The source of manganese and iron in the ores and the source of silica of the banded chert are thought to be in submarine basic volcanism as well as in leaching from land and submarine volcanic rocks. Bedded cherts associated with the manganese and manganiferous iron deposits may have been deposited from soluble silica in sea water and hydrothermal solution either by chemical or biochemical reactions.
Both the manganese and the manganiferous iron deposits in this area suffered thermal metamorphism related to an early Cretaceous granitic activity. Original mineral phases in unmetamorphosed manganese ores are considered to have been manganese dioxide minerals, rhodochrosite with or without hausmannite, jacobsite, bementite, penwithite etc. The metamorphosed equivalents show a systematic mineralogical change corrcsponding to the metamorphic grades of the country rocks. Four grades of metamorphism, the chlorite-, biotite-, cordieriteand potash feldspar zones, all of which are identifiable in the metamorphic mineral assemblages of interbedded pelitic and psamitic sediments, are reflected in the manganese ores by the existence of rhodochrosite ore, braunite ore, manganese silicate-rich ore and manganiferous amphibole and pyroxene-bearing silicate ore, respectively. Original mineral species of the manganiferous iron ores seem to have included ferric oxide hydrate, iron carbonate, manganese oxides, manganese carbonate, amorphous silica, some hydrosilicates etc., and they have been converted to hematite, magnetite, rhodochrosite, rhodonite etc. in the metamorphosed ores.

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The Hida metamorphic belt is divided into three tectonic units, called western, central and eastern massif, respectively. The indications of lead-zinc mineralization ever reported are distributed exclusively in the central massif.
The skarn type lead-zinc mineralization is thought to have been closely related to the Inishi-type migmatite as is evidenced from their close mutual association. It is notable that the distribution of the Inishitype migmatite is also restricted within the central massif, in which the migmatite is found predominantly alongside the "metabasite" which is thought to be highly digestive migmatitic diorite and gabbro complex.
The central massif of the Hida metamorphic belt extends NNW and SSE with approximate width of 25 km and is quite unique against the other units of the Hida metamorphic belt, viewing from metamorphic grade, geological structure and species of migmatite, in addition to the fact that it shows a remarkable negative anomaly of the residual gravity.

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The northern part of Sierra Madre Oriental is composed mainly of calcareous and clastic sediments of Upper Jurassic to Upper Cretaceous age. The initial transgression had started in Divesian-Kimmeridgian stage, and thick layers of evaporites were accumulated under sublittoral condition. Coahuila Peninsula and Tamaulipas Island were still emerged at the begining of Neocomian stage. Paleozoic basement was then covered unconformably by Lower Cretaceous sediments. Early Cretaceous transgression spread over almost all the area, and deep and/or shallow depositional environments persisted until Albian stage according to the various evolutional stages of Mexican Geosyncline. Upper Cretaceous sedimentation was regressive, and the area was totally uplifted at the end of this age. The Mesozoic sediments were strongly folded and faulted, accompanied by Tertiary volcanics and intrusives during Laramide Orogeny, and the saline residues appeared to have played an essential role in this deformation. Recent geochronological data supplied from a cooperative survey between Metal Mining Agency of Japan and Consejo de Recursos Minerales indicate that the principal folding period was in 45-35 m.y. and the main igneous activities were also in Paleogene. However, some plutonic rocks are dated as Miocene-Pliocene.

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