Влодавец, В. И. Нефелино-апатитовые месторождения в Хибинских

Nephelinc-Apatite Deposits of the Chibiua-Titndras in the Kola Peninsula. V. I. Vlodawec. In summer 1928, an investigation was undertaken by the Institute for Scientific Exploration of the North of the Kookisvumchorr apatite deposit which was discovered in 1921 by an expedition under Prof. A. F e r - s m a n and more extensively studied by A. N. L a b u n t s o v , in 1927. The investigation was carried out by the writer, with collaboration of A N. M o r o z o v , Topographer, and N. S. S k r o z n i k o v a , Chemist. During reconnaissance work following new occurrences of apatite were discovered: 1) in the valley of the river Vortkewy, at the feet of the southwestern slope of Kookisvumchorr, in the vicinity of the pass leading from the Vortkewy valley into that of the Tulyok-river; and 2) on both slopes of Pinwychorr, both localities being almost direct continuation of the Yuksporr-deposit discovered by A. N. L a b u n t s o v in 1927 at the summit of the southwestern branch of the Yuksporr-range, actually bearing the name of Pinwychorr. The outcrop at the pass, the Kookisvumchorr and Pinwychorr deposits as well as those discovered in 1923 and 1926 in the Apatite branch and in Rasvumchorr, are likely to have once formed either a series of constricted lenses or an entire one trending 315°NW and dipping NE at 3(P, actually divided into a series of the above named single deposits by deep valleys which originated in consequence of later phenomena. The nepheline-apatite rock which is filling the lense, in the Kookis­ vumchorr and Pinwychorr deposits, is resting at about the boundary be tween nepheline-syenite (the chemical analysis is given in p. 23) and the rocks of the ijolite-urtite series, the former rock being overlying and the latter underlying. The contact rocks which were formed at the boundary with adjacent rocks (both at the hang ing and the lying flank) are, to judge from their mineralogical composition, an ijolite, yet with granoblastic structure. The sample 13 (microphotographs 8 and 9) from the contact zone at the lying flank is a rock of variegated structure. Bands consisting of coarse grains of nepheline alternate with those of fine grains of nepheline aegirine, mica, sphene, apatite and titano-magnetite. 53