The monazite placers of Sri Lanka are among the world's most thorium rich sediments. This study of the stream sediments and rocks from an area in the southwest of Sri Lanka shows that the highly metamorphosed aluminous schists and gneisses and also granitoid rocks of the Highland and Southwest Groups ofthe Precambrian of Sri Lankaare the ~robable source rocks for the thorium-rich monazite. Themanmatic fluids known to have pervaded the aluminous sediments during the intense folding and metamorphism under granulite facies conditions are considered to have been thorium rich. The P-T conditions of metamorphism proved to be ideal for the formation of a variety of gem minerals including gem monazite and other associated heavy minerals.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.