stripes
This dyke, 1.3-1.5 m thick, is formed from basic leucite- phlogopite lamproite. It cuts lower Cambrian marls, which overly the Precambrian basement, along sharp contacts and the enclosing rocks are metamorphosed to hornfelses and chloritized. The dyke has a zoned structure with the central part porphyritic and the outer part aphyric. The porphyritic lamproite of the centre is formed from rare altered phenocrysts of olivine, leucite and laths of phlogopite. The fine-grained outer part comprises mainly phlogopite and polygonal grains of pseudoleucite with microlites of altered olivine, clinopyroxene, magnetite and apatite set into a finer grained mass of phlogopite, chlorite and possible alkaline amphibole. The mica is both ferruginous phlogopite and biotite with a very low aluminium and titanium content (about 3% TiO2).
MAKHOTKIN, I.l., ARAKEL'YANZ, M.M. and VLADYKIN N.V. 1989. On the age of the lamproites of the Aldan Province. Doklady Akademii Nauk SSSR, 306: 703-7.
ORLOVA, M.P. 1990. Mesozoic stage of magmatism. In G.V. Polyakov and V.V. Kepezinskas (eds) Potassic alkaline magmatism of the Baikal-Stanovoy rift system. 65-123. Nauka, Siberian Division of the USSR Academy of Sciences, Novosibirsk.