Metamorphism, regional

Host rocks in the Hitachi area suffered regional metamorphism, contact metamorphism by Cretaceous granitic rocks and hydrothermal alteration associated with sulfide mineralization. 

Kerrick, D.M. and Caldeira, K. (1993) Paleoatmospheric consequences of CO2 released during early Cenozoic regional metamorphism in the Tethyan orogen. Chem. Geol., 108, 205-230. 

Depending on the conditions of the main agents of metamorphism, four kinds of metamorphism are recognized. These are burial, contact, thermal and regional metamorphism. 

The extent to which isotopic fractionation occurs at sub-1000°C temperatures in magmatic and regional metamorphic systems is unstudied in detail, but limited natural and experimental data in granitic systems suggest that measurable fractionation may occur under these conditions. This fractionation might be applied in studies of magmatic and ore evolution, either for thermometry or mineral deposit exploration. 

Heinrich CA (1986) Eclogite facies regional metamorphism of hydrous mafic rocks in the Central alpine Adula nappe. J Petrol 27 123-154... 

Klein C (1974) Greenalite, stilpnomelane, minnesotaite, crocidolite, and carbonates in a very low-grade metamorphic Precambrian iron-formation. Can Min 12 475-498 Klein C (1978) Regional metamorphism of Proterozoic iron-formation, Labrador Trough, Canada. Am Min 63 898-912... 

In thermal metamorphism, biotite occurs in the clorite-sericite facies as a dispersed phase in the argillitic matrix and is stable up to low-grade cornubianites. In regional metamorphism, biotite is typical of argillitic and pelitic rocks up to the staurolite-garnet facies (biotite, biotite-sericite, biotite-chlorite, and albite-biotite schists, and garnet-staurolite micaschists). 

In metamorphic rocks, muscovite occurs in low-grade terrains of the regional metamorphism (albite-chlorite-sericite schists). It must be noted here that the term sericite identifies fine-grained white micas (muscovite, paragonite). 

Biotite Gabbros, norites, diorites, granites, pegmatites Phyllites, chlorite-sericite schists, biotite facies of the regional metamorphism, gneisses ... 

Feldspars are the most abundant minerals of igneous rocks, where their ubiquity and abundance of their components influence normative classifications. They are also abundant in gneisses, and may be observed in several facies of thermal and regional metamorphic regimes. Notwithstanding their alterability, they are ubiquitously present in sedimentary rocks, as authigenic and/or detritic phases. Only in carbonaceous sediments is their presence subordinate. 

Peltonen, P. Lamberg, P. 1991. Chromian spinel in Svecofennian ultramafic intrusions compositional evolution during fractional crystallization, cooling, regional metamorphism and alteration. Geological Survey of Finland, Special Paper 2, 23-31. 

In marbles and skarnoids, the consistent U-Ba-Mo-Pb-V-Zn association and absence of Th, the rare occurence of graphite, and the REE patterns in uraninite are evidences for a possible synsedimentary and/or diagenetic origin of the uranium and associated metals. This primary metal stock located in impure dolostone with possible evaporitic layers (as indicated by the presence of scapolite and kampfite in skarnoids) would have been more or less remoblllzed during regional metamorphism and tectonics. 

The rocks in the study have undergone zeolite facies regional metamorphism but locally intense penetrative fabrics are recognized in areas adjacent major faults. 

FarreU JW, Pedersen TF, Calvert SE, Nielsen B (1995) Glacial-interglacial changes in nutrient utilization in the equatorial Pacific Ocean, Nature 377 514-517 Ferry JM (1992) Regional metamorphism of the Waits River Formation delineation of a new type of giant hydrothermal system, J Petrol 33 45-94... 

Wickham SM, Taylor HR (1985) Stable isotope evidence for large-scale seawater infiltration in a regional metamorphic terrane the Trois Seigneurs Massif, Pyrenees, Prance. Contrib Miner Petrol 91 122-137... 

In regional metamorphic rocks and contact metamorphic (metasomatic) rocks, new mineral crystals grow in solid rocks in which there was a change in conditions. However, the process is not the same as straightforward solid state growth or recrystallization. Since volatile components such as H O and CO, which were originally present in the rock, are involved, it is better to assume a... 

Regional metamorphism proceeds in a wide area, and characteristic mineral paragenesis appears in zones depending on the temperature and pressure conditions that were confronted by the original rock. These are called metamorphic... 

Figure 13.5. White mica in a regional metamorphic rock using the decoration method [5]. 

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