Stratabound pyritic sulphide occurrences in an ophiolite rock assemblage near Tumut, New South Wales

Abstract

Abstract Pyrite‐rich sulphide with minor chalcopyrite, sphalerite, marcasite, and pyrrho‐tite, occurs in low‐grade metabasaltic rocks near Tumut, New South Wales. The rocks are chemically akin to modern abyssal tholeiites and form part of a well‐developed ophiolite rock assemblage. Rock alteration and sulphide mineral assemblages are similar to those found in pyrite‐rich sulphide deposits in the Troodos ophiolite complex, Cyprus, and in other ophiolite complexes, although low‐grade regional metamorphism has caused textural and mineralogical changes. It is suggested that the Tumut occurrences formed from submarine volcanic exhalations, associated with abyssal theoliite volcanism; and that the ophiolite rock assemblage formed contemporaneously with a sea‐floor spreading episode. The ophiolite rock assemblage was later obducted, perhaps during continental collision.