Toyama breccia pipe, which outcrops in the area of Kamihikawa dam about 8 km east from Enzan, Yamanashi Prefecture, shows features of diatreme, intruded at about 6 Ma into Tokuwa granitic body. Mineralogy and distribution of alteration minerals in breccia pipe were investigated, using samples collected in the tunnel of Kamihikawa dam, by X-ray powder diffraction (XRD) and scanning electron microscopy equipped with an energy-dispersive type spectrometer (SEM-EDX). Spatial and temporal characters of hydrothermal alteration in the Toyama breccia pipe have been addressed in the present study together with clay mineralogy, comparing with those reported from similar breccia pipes and clay deposits distributed in the southern Fosa Magna region.
Four types of alteration including weathering were identified by XRD and SEM-EDX analyses: 1) hydrothermal alteration with mainly epidote and chlorite formation, similar to so-called propyritization, 2) hydrothermal alteration associated with pyrophyllite, kaolinite, illite, and mixed layer minerals, 3) weathering characterized by vermiculite, smectite, kaolin, and goethite formation, and 4) hydrothermal alteration with zeolite minerals. The four types of alteration which occurred at different stages, in turn, from 1) to 4) were superimposed each other along radial fractures developed inside the breccia pipe. Igneous and hydrothermal activities related to the formation of diatreme and alteration of Type 2) in Toyama that occurred at 6–3 Ma are noteworthy as events intimately linked with other activities occurred during Miocene-Pliocene ages in the southern Fosa Magna.
Characteristics of soils, fertilizers, agriculture and forestry are biological production using ecosystem services in the natural and/or artificial fields. In these fields, roles of clays and other inorganic materials are to provide essential and beneficial nutrient elements to plants and animals, and to conserve the environments for the plants and animals in suitable conditions for the biological production. Looking back on the past 60 years, allophane, imogolite and pedogenic opals were discovered in volcanic ash soils; changes in concentration of many elements during the formation of Andosols/Andisols from tephra were elucidated; regional maps of clay mineral distribution in soils were published. In recent years, a lot of efforts were made to analyze and to restore the soils damaged by tsunami and radio-cesium in 2011, eastern Japan. In order to further enhance the contribution of these research fields to the public, nondestructive analyses of these materials in individual cases may be effective for getting a clue. Analysis of phosphate cycling in the paddy field soil was exemplified.