Petrology of the Mid-Paleoproterozoic Tiksheozero Ultramafic‒Alkaline‒Carbonatite Complex (Northern Karelia)

Major and Trace-Element Composition of Minerals in the Paleoproterozoic Tiksheozero Ultramafic–Alkaline–Carbonatite Complex, Russia: Insight into Magma Evolution

“…It is a central-type concentrically zoned multi-phase intrusion 24 km 2 in area. The complex is split by faults into several blocks: Central, Shapkozero, and Tiksheozero (Figure 1), which were described in detail in [5]. Three intrusive phases are distinguished: (1) lowalkali ultramafic rocks (dunites, wehrlites, clinopyroxenites, and gabbro); (2) alkaline rocks subdivided into foidolites (alkaline clinopyroxenites, jacupirangites, ijolites, melteigites, urtites) and a group of nepheline syenites and theralites; (3) calcite carbonatites and associated carbonate-silicate rocks.…”

“…The previous studies of this complex have been mainly focused on the geochronological dating and isotope-geochemical analysis of carbonatites, whereas silicate rocks that compose most parts of the complex remained poorly studied [2][3][4]. Our recent studies [5,6] were dedicated to the detailed petrographic, mineralogical, and chemical examination of all rock varieties and included microprobe study of minerals, as well as the petro-and geochemical and isotope-geochemical (Sr-Nd-Hf-Pb-Os) study of all rocks.…”

“…The obtained data allowed us to shed light on the petrology of the complex, some genetic aspects of the relations between the alkaline silicate phases of the complex, and to propose a genetic model of their formation [5]. Two alternative models of the formation of the low-alkali ultramafic-mafic and alkaline phases of the massif were proposed: (1) from a single mantle source through successive two-stage melting and (2) three-stage model related to the ascent and melting of the mantle plume [6].…”

“…In addition, many questions regarding the genetic relationship of the ultramafic part of the massif with alkaline magmas remained incompletely solved. In this work, these problems are discussed using first obtained in situ LA-ICP-MS data on minerals from all intrusive phases of the Tiksheozero complex in combination with previously obtained microprobe and geochemical studies ( [5,6]).…”

Минеральный Потенциал Палеопротерозойского Ультрамафит-Щелочно-Карбонатитового Интрузивного Тикшеозерско-Елетьозерского Комплекса (Северная Карелия, Россия)

“…Данные о минеральном потенциале палеопротерозойского Тикшеозеро-Елетьозерского ультраосновного-щелочно-карбонатитового интрузивного комплекса, расположенного в Северной Карелии, получены в результате геолого-петрологических, минералого-геохимических, геохронологических и минерагенических исследований среднепалеопротерозойского магматизма данной территории [9,10,11,12,18,26,28]. Специфика рассматриваемого комплекса заключается в том, что этот комплекс принадлежит в возрастном отношении к наиболее древним образованиям мира.…”