A pumpellyite-occurring zone can be distinguished from a biotite-occurring zone in the Paleozoic to Mesozoic terrain of the Kuzakai-Morioka area, northern Kitakami Mountains. The former is presumably a remnant of earlier low-temperature regional metamorphism, while the latter a recrystallized product by the later contact metamorphism due to Cretaceous granitic intrusions.
In the pumpellyite-occurring zone the characteristic mineral assemblage is epidote+pumpel-lyite+chlorite+actinolite in greenstones and phengitic muscovite+chlorite in pelitic rocks. Prehnite occurs only as a vein-forming mineral in greenstones, but is found rarely in the matrices of calcarious pelitic and psammitic rocks.
This area had been metamorphosed in the pumpellyite-actinolite facies grade before the Cretaceous intrusions. However, actinolite is confined to occur in relatively Mg-rich greenstones. In the epidote+pumpellyite+chlorite+actinolite assemblage, the Fe/(Fe+Al) ratios of epidote and pumpellyite and the Mg/(Mg+Fe) ratios of chlorite and actinolite tend to be higher in the east than in the west of this area, suggesting a decrease of prevailing temperature eastward during the metamorphism.
The marked gap in the celadonite content of muscovite between the pumpellyite- and biotite-occurring zones, and the sporadic occurrence of zoned epidote showing an abrupt decrease in Fe/ (Al+Fe) at its core-rim boundary in a part of the pumpellyite-occurring zone support the idea that the low-grade regional metamorphism took place prior to the contact metamorphism.

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Jadeitic pyroxenes are found from the metabasites of a coherent suite of high-pressure rocks in the Horokanai-Kamietanbetsu area. Jadeitic pyroxene-bearing rocks occur as massive bundins or schistose rocks intercalated with Na-amphibole-albite-bearing basic schists. Jadeitic pyroxenes are associated with Na-amphibole, lawsonite, chlorite, aragonite, albite and quartz. XJa of jadeitic pyroxenes in contact with quartz and albite ranges from 0.56 to 0.74. The mode of occurrence and XJa of jadeitic pyroxenes suggest that the Kamuikotan high-pressure sequence in the study area was formed in the albite stability field and close to that of jadeite-quartz assemblage.

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Many masses and veins of rodingite derived from hornblende gabbro occur in serpentinized harzburgite of the Mineoka tectonic belt, Chiba. The original gabbro seems to have been composed mainly of plagioclase (Ane₈₀Ab₂₀) and actinolitic hornblende with a small amount of orthopyroxene (En₇₅Fs₂₃Wo₂). Plagioclase changes progressively to thomsonite, prehnite and hydrogrossular, hornblende to cummingtonite and chlorite, and orthopyroxene to talc. Four metasomatic zones are recognized from gabbro to serpentinite as follows : 1) the least altered zone consisting of plagioclase, hornblende and cummingtonite ; 2) thomsonite zone of thomsonite, prehnite, hornblende, cummingtonite and chlorite ; 3) prehnite-hydrogrossular zone of prehnite, hydrogrossular, cummingtonite and chlorite ; and 4) hydrogrossular zone of hydrogrossular and chlorite. A small amount of orthopyroxene are distributed in all zones with talc. Plagioclase is altered together with hornblende, although the calcium contents of alteration products derived from both minerals show a negative correlation.
The chemistry shows a characteristic variation in the altered zones as follows : 1) Al and O contents are nearly constant ; 2) Ca and H tend to increase toward the highly altered zone ; 3) Si, Fe and alkalis show the reverse trend ; 4) Mg abounds at both of fresh and highly altered zones.
The water content of hydrogrossular increases with the metasomatism: i.e. The 2X value of Ca₃Al₂(SiO₄)_3-x(O₄H₄)_x increases to 1.2-2.1 in the prehnite-hydrogrossular zone, and 1.9-2.4 in the hydrogrossular zone.
The necessary amount of calcium for the formation of rodingite is supplied from both of hornblende in the orignal gabbro and surrounding peridotite. In rodingite occur many veinlets consisting of tobermorite, xonotlite, prehnite and hydrogrossular. In the least altered zone, the same metasomatic zonation of rodingite is found along these veinlets. The process of rodingite formation, therefore, is shown by a sequential reaction between Ca-rich solutions and hornblende gabbro.

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