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Plagioclase varieties from leucogranites of the Raumid pluton (Pamirs) were studied by isotope Rb–Sr method. The studied varieties are: (1) fresh, crystal-clear magmatic oligoclase and (2) altered by deuteric saussuritization, turbid plagioclase. Comparison of data obtained for the coexisting varieties shows that saussuritization of the leucogranites led to Rb and Sr content and 87Rb/86Sr growth, and (87Sr/86Sr)0 distortion. This imply gain of alkaline and alkaline earth elements during saussuritization. The case of the Raumid pluton suggests a possibility of the gain from country rocks. [ABSTRACT FROM AUTHOR]

This work presents isotope Sm-Nd data obtained for bulk samples of granites of all 8 emplacement phases of the Raumid granite massif, which occurred 35 Ma ago at a hypabyssal depth during the orogenic stage of development of Southern Pamir fold system. The Sm/Nd ratio in studied collection of granite samples ranges between 0.091 and 0.323; the ε( T) value is-4.0. The Sm-Nd isotope study results suggest that all granite varieties distinguished in the Raumid massif are comagmatic formations and contamination and hybridization processes did not play any role in REE distribution in granites. At this, the source of parental magma did not change during granite generation. We assume that the only process, resulted in the trace element evolution in granites, was differentiation of three batches of magma sequentially uplifted from the source. [ABSTRACT FROM AUTHOR]