Comparative mmeralogical characteristics of alkaline massifs Dunkeldyk and Darai-Piez (Tajikistan)

Faiziev A. R.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2016. V. 145. N 2. P. 20-29

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Language: Russian

Abstract

Comparison of mineralogical characteristics of these two massifs of alkaline rocks and carbonatites has revealed that typomorphic minerals of Dunkeldyk massif are represented by fluorcarbonates of rare earths (parisite and bastnäsite) and the REE-calcium phosphate-silicate (britholite), but for Darai-Piez are typical pyrochlore and other rare niobium-bearing minerals (zirsilite, kentbrooksite, baotite, cesium kupletskite, etc). There are fluorite, celestine, gypsum and anhydride widespread in Dunkeldyk, apatite, garnet and phlogopite are also characteristic for this massif. Thorium minerals (thorite, turkestanite) are developed in Darai-Piez, as well as uranium-thorium mineral (arapovite), and rare earth and yttrium minerals (stillwellite, tadzhikite, kapitsaite, miserite, etc.). Darai-Piez is enriched also in minerals of boron (reedmergnerite, leucosphenite, tienshanite, hyalotekite, etc.), lithium (polylithionite, baratovite, sogdianite, etc.), beryllium (leucophanite, epididymite, moskvinite, etc.), zirconium (bazirite, eudialyte, zeravshanite, etc.), barium (baotite, pabstite, surhobite, etc.), and cesium (cesium kupletskite, teljushenkoite, sokolovaite, etc.). Such difference in mineral composition of two massifs may be explained by the deeper erosion level of Darai-Piez, as compared to the Dunkeldyk massif.

Key words: massif, alkaline rocks, carbonatite, mineral, vein, veinlet, lens, pocket, body.