| Summary: | The sulfur isotope geochemistry of the Khibina and Lovozero agpaitic massifs provides an opportunity to understand the role of plume-lithosphere interaction processes responsible for the Paleozoic alkaline igneous activity in the north-eastern part of the Fennoscandian Shield. The stable sulfur isotope δ 34S analysis using triple collector isotope ratio mass spectrometer (IRMS) has been carried out on the pentlandite, chalcopyrite and pyrite from nepheline syenites. The δ 34S values for pentlandite from Khibina rocks range from +0.69 to +2.06 ‰ relative to the Vienna Canyon Diablo Troillite standard (VCDT), and the pyrite has significantly higher δ 34S values up to +4.92 ‰ VCDT. The pentlandite from the Lovozero samples has value +1.48 ‰ VCDT, δ 34S values of chalcopyrite is +2.85 ‰ VCDT. The maximum positive δ 34S values are obtained for Lovozero pyrite, which vary from +5.41 to +6.30 ‰ VCDT. Comparison of sulfur-geochemical features of Khibina and Lovozero nepheline syenite with δ 34S data for the carbonatites from the Khibina, Sallanlatvi, Seblyavr, Vuoriyarvi, Salmagora and Kovdor massifs show later carbonatite formation relatively to associated alkaline rocks. Geochemical sulfur isotope δ 34S investigations emphasizes that parental magmas of the Khibina and Lovozero alkaline massifs were derived from a metasomatized subcontinental lithospheric mantle (SCLM). We suggest that high-?34S signature on the SCLM (δ 34S of +1 to +6 ‰ VCDT) can be explained by subduction of the high-δ 34S Archaean crust. Геохимия изотопов серы Хибинского и Ловозерского агпаитовых массивов дает возможность понять роль плюм-литосферных процессов, ответственных за палеозойскую щелочную магматическую активность в северо-восточной части Фенноскандинавского щита. Изотопный состав серы (δ 34S) получен для пентландита, халькопирита и пирита из нефелиновых сиенитов с использованием масс-спектрометра с тройным коллектором (IRMS). Значения δ 34S пентландита из пород Хибинского массива варьируют от +0,69 до +2,06 ‰ относительно стандарта ...
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