...Frederick Walker; A. Poldervaart Abstract "A 500 foot sill of dolerite from Hangnest in the Calvinia division of the Cape Province (South Africa) exemplifies very clearly two well-marked features of the thicker Karroo sills: (1) Very slight amount of crystallization differentiation; (2) Marked...

...<0.704) are suggestive of predominantly asthenospheric mantle derivation. N–S dykes, which are the most numerous, resemble the Ferrar magma type of Antarctica and the rare Hangnest and Kraai River magma types of the Karoo. The N–S dykes evolved by assimilation and fractional crystallization (AFC), most...