Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Zakhrebetninskii

stripes

Occurrence number: 
136-09-002
Country: 
Russia
Region: 
Enesei
Location: 
Longitude: 90.25, Latitude: 61.03
Carbonatite: 
No

This occurrence occupies about 20 km2 and is composed principally of peralkaline syenites; calc-alkaline and nepheline syenites are also present. The last forms several small lenses and consists of albitized alkali feldspar (67%), nepheline replaced by cancrinite (18%), analcime (2%), aegirine (13%) and biotite (1%) with accessory orthite, zircon, apatite and magnetite. Nepheline-bearing syenites contain 3-5% nepheline. The peralkaline syenites contain up to 82% alkali feldspar with albite-oligoclase 14% and biotite plus alkali amphibole 4%.

Age: 
K-Ar on peralkaline syenite gave 475 and 486_+6 Ma and on nepheline syenite 478_+8 Ma (Nozhkin and Trofimov, 1982).
References: 

KORNEV, T.Yu, DATSENKO, A.V. and BOZIN, A.V. 1974. Riphean magmatism and ores from the Enisei mountains. Nedra, Moscow. 132 pp.
NOZHKIN, A.D. and TROFIMOV, Yu.P. 1982. The peralkaline granite-syenite association of Srednevogovsky massif (Enisei ridge). In V.S. Sobolev (ed) Geology of coloured metal deposits from the folded margin of the Siberian Platform. 61-9. Nauka, Novosibirsk.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith