Metasomatic rock

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... 

Ramberg, H., "The Origin of Metamorphic and Metasomatic Rocks, p. 49, University of Chicago Press, Chicago, 1952. 

Reed, M. H., 1977, Calculations of hydrothermal metasomatism and ore deposition in submarine volcanic rocks with special reference to the West Shasta district, California. Ph.D. dissertation, University of California, Berkeley. 

Muscovite is the main term of the common dioctahedral micas, and it is found in acidic intrusive rocks (biotite and biotite-muscovite granites), although in subordinate quantities with respect to biotite. It is a common mineral in aplitic rocks and is peculiar to fluorine metasomatism in the contact zones between granites and slates ( greisenization ). 

The rocks at Morila record an intimate interplay between magmatism, contact metamorphism (and metasomatism), deformation, and mineralization. The spatial, temporal, and textural associations between contaminated post-D2 intrusions, contact metamorphism, and polymetallic post-D2 mineralization strongly suggests an intrusion-related origin for Morila. Other controls on Au mineralization include ... 

Alteration at Michelin is dominated by intense soda metasomatism and potash depletion, coupled with locally intense hematization much of the mineralization consists of fine-grained uraninite within sodium-rich silicates such as aegirine and arfvedsonite. The recently discovered Jacques Lake deposit, which is an important resource in its own right (about 17 million pounds UsOs), has many similarities to Michelin, although its metavolcanic host rocks are compositionally distinct. The age of the uranium mineralization in these deposits is... 

O, H, C, S, and N isotope compositions of mantle-derived rocks are substantially more variable than expected from the small fractionations at high temperatures. The most plausible process that may result in variable isotope ratios in the mantle is the input of subducted oceanic crust, and less frequent of continental crust, into some portions of the mantle. Because different parts of subducted slabs have different isotopic compositions, the released fluids may also differ in the O, H, C, and S isotope composition. In this context, the process of mantle metasomatism is of special significance. Metasomatic fluids rich in Fe +, Ti, K, TREE, P, and other large ion lithophile (LIE) elements tend to react with peridotite mantle and form secondary micas, amphiboles and other accessory minerals. The origin of metasomatic fluids is likely to be either (1) exsolved fluids from an ascending magma or (2) fluids or melts derived from subducted, hydrothermally altered crust and its overlying sediments. 

Taylor BE, O Neil JR (1977) Stable isotope studies of metasomatic Ca-Fe-Al-Si skarns and associated metamorphic and igneous rocks, Osgood Mountains, Nevada, Contr Miner Petrol 63 ... 

The one-time addition of fluids can be regarded as a one-time fluid metasomatism of the solid rocks just as it starts melting. This is a potential important model for mantle metasomatism. 

The amount of one-time fluid metasomatism is related to the mass of the melting zone source rocks by... 

Ruby crystals with a similar texture are found at a contact metasomatic deposit in Myanmar, and are called trapiche rubies. Sapphires with similar textures are also known. Trapiche ruby crystals occur sporadically in marble formed by contact metasomatism due to the intrusion of a granitic magma into Mg-containing limestone. Trapiche sapphire is also formed by the contact metasomatism of Al-rich sedimentary rocks. 

When a crystal is formed and becomes large in the mother sedimentary rocks metamorphosed, by contact metasomatism, crystals with similar textures are often formed. Chiastolite, a form of andalusite (Al SiO ) with a particular texture, may be such an example. 

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