An unusual clinopyroxene with complex lamellar intergrowths from an eclogite in the Sunndal-Grubse ultramafic mass, Almklovdalen, Nordfjord, Norway

Abstract

SummaryClinopyroxene crystals with complex lamellar intergrowths of orthopyroxene and garnet are described. The orthopyroxene lamellae are irrationally orientated within the clinopyroxene host although the optical relationships of these minerals are consistent with (100) exsolution in clinopyroxene. The intergrowth is nevertheless considered to be the result of exsolution processes. Possible modes of origin are reviewed together with the general significance of exsolved pyroxenes in eclogite- and granulite-facies associations.