Mineralogy and main petrology aspects of Malyutka massif of the Khudolaz complex (Southern Urals)

Detailed mineralogical studies of Malyutka massif rocks of the Khudolaz differentiated complex have been carried out. Firstly the chemical compositions of rock-forming and many accessory minerals have been identified and characterized. Based on the results of petrographic and mineralogical studies in the rock formation history the magmatic and post-magmatic (hydrothermal-metasomatic) stages were identified. The early cumulus (olivine-spinel pair 1074-1118 °C) and late intercumulus (hornblende-acid plagioclase pair 662-694 °C) magmatic stage minerals crystallization temperature by empirical geothermometers was estimated. The rocks of massif were saturated by hornblende (33-47 vol. %). We concluded that massif was formed from water-saturated magma, divided from the cumulus horizon of a hypothetical deep magma chamber. Using the method of geochemical thermometry, the composition of the initial melt was determined, that matched magnesium-rich basalt with a temperature at the injection of about 1180 °C.