Alkaline Rocks and Carbonatites of the World

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

Lusenga

stripes

Occurrence number: 
180-00-004
Country: 
Zambia
Location: 
Longitude: 29.17, Latitude: -9.42
Carbonatite: 
No

The Lusenga syenite is an approximately circular, 8 km diameter intrusion with two smaller syenite bodies to the northeast (Brewer et al., 1979). The rocks are described as consisting of orthoclase, subordinate albite, interstitial quartz (although three of four chemical analyses indicate 2.2-2.7 normative nepheline) and chlorite, probably after biotite. One analysed specimen gives 6.6% normative acmite.

Age: 
A Rb-Sr isochron, based on five samples, gave an age of 1134±8 Ma.
References: 

BREWER, M.S., HASLAM, H.W., DARBYSHIRE, D.P.F. and DAVIS, A.E. 1979. Rb-Sr age determinations in the Bangweulu Block, Luapula Province, Zambia. Report, Institute of Geological Sciences, 79/5: 1-11.

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