Alkaline Rocks and Carbonatites of the World

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

Alligator Lake


Occurrence number: 
Northwest Territories, Yukon
Longitude: -135.37, Latitude: 60.42

Alligator Lake is an alkaline volcanic centre located in southern Yukon, Canada. It occurs at the northern extremity of the Stikine volcanic belt, belonging to the North Cordilleran Volcanic Province. Structurally, it is composed of two cinder cones capping a small shield volcano formed of a basaltic succession. Country rocks belong to the granitoid Cretaceous Coast Plutonic Complex and the Tertiary Skukum Volcanic Group. Lava flows, cinder cones and scoria are composed of alkali olivine basalt, basanite, and tholeiitic basalt and are found ~5 km north west of the northern protrusion of the lake. Basanite contains normative nepheline (2.2-6.3%) and flows often include xenoliths of country rock granite and spinel lherzolite along with olivine, pyroxene, and spinel megacrysts. Petrography, Sr-Nd isotopic data, and whole rock major and trace element data can be found in Eiché et al. (1987).

3.3 ± 0.4 Ma (cinder cone), 3.12 ± 0.03 Ma (flow) K-Ar (Edwards and Russell, 2000)

EDWARDS, B.R. & RUSSELL, J.K., 2000. Distribution, nature, and origin of Neogene-Quarternary magmatism in the north Cordilleran volcanic province, Canada. Bulletin of the Geological Society of America 112 (8) pp 1280-1295 EICHÉ, G.E., FRANCIS & D.M., LUDDEN, J.N., 1987. Primary alkaline magmas associated with the Quarternary Alligator Lake volcanic complex, Yukon Territory, Canada. Contributions to Mineral Petrology 95 pp 191-201

Fig 1. Alligator Lake cones and flows (Eiché et al., 1987): see reference for details on units
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith