Epifanovite,NaCaCu5(PO4)4[AsO2(OH)2] · 7H2O: a New Mineral from the Kester Deposit,Sakha (Yakutia) Republic,Russia

Geology of Ore Deposits - Epifanovite, NaCaCu5(PO4)4[AsO2(OH)2] · 7H2O, a new natural copper, sodium and calcium arsenate–phosphate, has been found in a quartz–phosphate pocket...     

Kampelite,Ba3Mg1.5Sc4(PO4)6(OH)3·4H2O,a new very complex Ba-Sc phosphate mineral from the Kovdor phoscorite-carbonatite complex (Kola Peninsula,Russia)

Mineralogy and Petrology - Kampelite, Ba3Mg1.5Sc4(PO4)6(OH)3·4H2O, is a new Ba-Sc phosphate from the Kovdor phoscorite-carbonatite complex (Kola Peninsula, Russia). It is orthorhombic, Pnma,...     

Corundum-group minerals in rocks of the Khibiny alkaline pluton,Kola Peninsula

Five minerals of the corundum group have been identified in the Khibiny pluton with certainty. Corundum proper and karelianite occur only in hornfels after volcanic and sedimentary rocks. Xenoliths of hornfels mark the ring faults that bound foidalite within the field of foyaite. Hematite occurs in hydrothermally altered nepheline syenite and crosscutting hydrothermal veins related to the ring faults. Minerals of the ilmenite-pyrophanite series are present in all rocks of the pluton, including veins. Accessory ilmenite in foyaite varies from the manganese variety and pyrophanite in the inner and outer parts of the pluton to manganese-free ilmenite in zone of the Main Ring Fault. In xenoliths of volcanic rocks and alkaline ultramafic rocks, ilmenite is enriched in magnesium. The zoning in distribution of the above-mentioned minerals and the character of variation in their compositions from margins of the pluton to its center are consistent with the petrochemical zoning formed as a result of foyaite alteration of near ring faults.     

Typochemistry of rinkite and products of its alteration in the Khibiny Alkaline pluton,Kola Peninsula

The occurrence, morphology, and composition of rinkite are considered against the background of zoning in the Khibiny pluton. Accessory rinkite is mostly characteristic of foyaite in the outer part of pluton, occurs somewhat less frequently in foyaite and rischorrite in the central part of pluton, even more sparsely in foidolites and apatite–nepheline rocks, and sporadically in fenitized xenoliths of the Lovozero Formation. The largest, up to economic, accumulations of rinkite are related to the pegmatite and hydrothermal veins, which occur in nepheline syenite on both sides of the Main foidolite ring. The composition of rinkite varies throughout the pluton. The Ca, Na, and F contents in accessory rinkite and amorphous products of its alteration progressively increase from foyaite and fenitized basalt of the Lovozero Formation to foidolite, rischorrite, apatite–nepheline rocks, and pegmatite–hydrothermal veins.     

Ulvöspinel from xenoliths of contact-altered volcanic and volcanosedimentary rocks in nepheline syenites of the Khibiny and Lovozero plutons

Ulvöspinel is a typical accessory mineral of xenoliths of volcanic and volcanosedimentary rocks in alkaline syenites of the Khibiny and Lovozero plutons. Ulvöspinel forms homogeneous Cr- and V-rich grains in slightly altered olivine basalts, basaltic tuffs, and tuffites and is enriched in Mn and Si in the course of contact-metasomatic alteration of these rocks. The strongly reduced conditions of contact metamorphism controlled by ascending flows of hydrocarbon gases and hydrogen sulfide gave rise to the subsolidus decomposition of primary ulvöspinel and Ti-high magnetite with the formation of ilmenite lamellae and then, with decreasing redox potential, of the second-generation latticed ulvöspinel lamellae.     

Structural and compositional zoning and formation conditions of the Greater Eastern Litsa BIF occurrence, Kola Peninsula

New geological and geochronological data on the Greater Eastern Litsa banded iron formation (BIF) occurrence demonstrate its similarity to the BIF of the Olenegorsk iron district in geology (lenticular orebodies with exponential distribution of their sizes), age (2.8 Ga), and typical structural and compositional zoning of orebodies. The temperature of ore formation (600–780°C) and BIF composition depend on the intensity of folding expressed in the fractal dimension D = 1.0–1.3 of a single layer. All BIF deposits of the Kola-Norwegian Megablock, including the Greater Eastern Litsa occurrence pertain to the one system. Variation m their composition is controlled by the size of orebodies (capacity of oxygen buffer) and the energy of metamorphic reactions, which strongly depend on the intensity of folding.     

Topography formation as an element of lithospheric self-organization

In geologic objects of different characters and extents, the fractal properties of topography are related to the intensity of endogenic energy flows and the composition of geologic complexes. A good correlation between the topographic differentiation of the Khibiny pluton and the variables of different levels of its structural and compositional organization (mineral and chemical compositions of the rocks and minerals, rock texture, etc.) suggests that topography formation is an element of the self-organization of the Khibiny pluton. Analysis of the fractal dimension of topography in the Khibiny pluton, Primorye, and detailed areas in Transbaikalia revealed a coincidence of its maxima with the position of ore clusters, fields, and deposits, i.e., areas with the contents of elements significantly higher than their clarkes. All the above data suggest that the fractal properties of topography can be used as a prospecting criterio.     

Kalsilite of the Khibiny and Lovozero alkaline plutons,Kola Peninsula

Kalsilite—a typical mineral of ore-bearing zones of the Khibiny and Lovozero plutons—was formed after low-Si and high-K nepheline in one of three ways: (1) by relatively high-temperature replacement of Na with K; (2) due to orthoclase-kalsilite poikiloblastesis in foidolites and overlapping foyaites; or (3) by replacement of nepheline with zeolite.