Alkaline Rocks and Carbonatites of the World

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

Chavach

stripes

Occurrence number: 
136-08-014
Country: 
Russia
Region: 
East Tuva
Location: 
Longitude: 98.2, Latitude: 51.52
Carbonatite: 
No

Approximately 100 dykes of nepheline syenite 0.1-350 m thick and up to 2 km long are developed over an area of 6 km2. They are emplaced within schists. The majority of the dykes are albitized, a process that has destroyed the nepheline. The albite rocks contain biotite, aegirine-augite, fluorite, magnetite, and microcline-perthite relicts; accessories include zircon, britholite, thorite, molybdenite and betafite.

Age: 
Pb determinations on thorite gave 420±40 Ma (Zykov et al., 1961).
References: 

OSOKIN, E.D., LAPIN, A.V., KAPUSTIN, Yu.L., POHVISNEVA, E.A. and ALTUHOV, E.N. 1974. Alkaline provinces of Asia. Siberian-Pacific group. In L.S. Borodin (ed) Principal provinces and formations of alkaline rocks. 91-166. Nauka, Moscow.
ZYKOV, S.I., STUPNIKOVA, N.I., PAVLENKO, A.S., TUGARINOV, A.I. and ORLOVA M.P. 1961. The age of the intrusions from East Tuva and the Enisei Range. Geokhimiya. Akademiya Nauk SSSR, Moskva, 7: 547-60.

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