Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
Finding of calc-alkaline lamprophyres in association with alkaline rocks and carbonatites of Mushugai Khuduk (Mongolia)
Abstract
The Mushugai Khuduk alkaline carbonatitic volcano-plutonic complex in southern Mongolia is crosscut by numerous dykes. In this article, we describe a new findings of intermediate calc-alkaline lamprophyres (SiO2 ~53 wt. %). Mineralogical composition of the subvolcanic dykes corresponds to augite minettes passing into kersantites which prevail. The lamprophyres contain abundant xenocrysts as well as immiscible leucocratic ocelli. The lamprophyres are spatially associated with apatite-rich dykes (nelsonites) with preserved unique mingling textures between the silicate and carbonatite melt. Occurrence of calc-alkaline lamprophyres in association with nelsonites and carbonatites suggests important interaction between the metasomatised (phlogopite-clinopyroxene-apatite) lithospheric mantle and CO2-rich asthenospheric mantle during the formation of volcano-plutonic association of Mushugai Khuduk.
