An unusual occurrence of ultramafic and mafic rocks north of Mt Bischoff, Tasmania

Abstract

Plagioclase-bearing harzburgite, plagioclase lherzolite, basalt and dolerite intrude a sequence of mudstone, greywacke, pillowed basalt and chert in the Arthur River valley north of Mt Bischoff. The ultramafic rocks are concordant bodies characterised by absence of internal deformation structures, abundant primary mineral assemblages and cumulate textures. The ultramafics were most probably intruded as magma. Fine- to coarse-grained dolerite were intruded in the same zone, probably as dykes.