Shankers Bend Diatreme

Lying some 4 km east of the Similkameen pluton, the Shankers Bend diatreme is an irregularly shaped, concentrically zoned body about 1 km across, consisting of malignite, fenite and other alkaline rocks. Much of the diatreme comprises fenitized greenstone and greenstone breccia which grade out into unfenitized but shattered and brecciated rocks. The fenitized rocks are described as "analcitic, shonkinitic, and malignitic gneisses" (Rinehart and Fox, 1972, p. 58), but their petrography is not described in detail. Irregular bodies and dykes of carbonate rocks, sometimes brecciated, are believed to be carbonatites. Fuller descriptions are required to substantiate the peralkaline character of these rocks.