Alkaline Rocks and Carbonatites of the World

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

Lomi

stripes

Occurrence number: 
085-00-015
Country: 
Kenya
Location: 
Longitude: 36.25, Latitude: 1.83
Carbonatite: 
No

The present outcrop area of this volcano is 224 km2 but it may originally have been four times that. It has a caldera with well preserved western and northern walls (Dunkley et al., 1993). The northern and southern flanks are covered by younger basalts and the western margin obscured by Quaternary sediments. The eastern margin is defined and cut by faults marking the western side of the rift valley. The volcanic rocks are predominantly trachyte lavas but with intercalations of ignimbrite and air fall tuffs. They are cut by numerous trachyte and basalt dykes and stocks.

Age: 
K-Ar on trachyte from a flow gave 3.0±0.2 Ma (Dunkley et al., 1993).
References: 

DUNKLEY, P.N., SMITH, M., ALLEN, D.J. and DARLING, W.G. 1993. The geothermal activity and geology of the northern sector of the Kenya rift valley. British Geological Survey, Research Report. International Series SC/93/1: 1-185.KEY, R.M. 1987b. Geology of the Maralal area. Report, Geological Survey of Kenya, 105: 1-93.

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