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6895123 
Book/Book Chapter 
Metamorphism of dolomites and limestones 
Sharma, RS; Sharma, A 
2021 
Academic Press 
London, United Kingdom 
Encyclopedia of geology 
479-491 
English 
Dolomites and limestones are the common carbonate rocks in the Earth's crust. Their main mineral constituents are dolomite [CaMg(CO3)2] and calcite [CaCO3], with a variable silica content. These carbonate rocks originate on continental margins and also on the oceanic crust commonly as a salt of carbonic acid. Once deposited through sedimentary processes, metamorphic transformation can occur by thermal effects from contact with an igneous intrusion (contact or thermal metamorphism), or regionally from combined pressure and temperature effects through subduction within the plate tectonic cycle (regional metamorphism). The resulting changes in response to the environmental changes are progressive mineralogical transformations accompanied by decarbonation reactions, giving rise to silicate minerals talc, tremolite, diopside, forsterite and wollastonite. Extreme temperature around an igneous intrusion produces high metamorphic grade (sanidinite facies) calc-silicate mineral assemblages uniquely characterized by minerals like melilite, tilleyite, spurrite, rankinite, larnite, etc., not observed in pressure-dominant regionally metamorphosed carbonates. Since carbonate metamorphism transforms carbon within the plate tectonic cycle, the associated reactions play an important role in long-range changes (that include climate) by controlling reservoirs of carbon in the Earth, and the distribution of rare earth elements (REE) by preferred partitioning in carbonate minerals and hydrothermal fluids. Experimental, chemical modeling and ultra-high-pressure mineral inclusion studies are providing a much deeper knowledge of the transformations of carbonate (and its reduced forms) in deeper environments, thereby extending the metamorphic processes through to the earth's mantle. 
2nd 
Alderton, D; Elias, SA 
9780081029091