Significance of sedimentary structures in the Willyama complex, New South Wales

Their presence confirms lithological layering within the metasediments as bedding. These primary structures occur not only in low grade rocks as previously reported by other workers, but also in areas of medium and high grade metamorphism. Sedimentary structures include graded beds, cross beds, ripple marks, and ball and pillow structures. The observed parallelism of the early schistosity and bedding in the Broken Hill area has previously led to the idea of transposition by isoclinal folding. In the areas mapped, small scale transposition is precluded on the basis of uniform facing of sedimentary structures over wide areas, and the existence of large areas in which the early schistosity is oblique to bedding.