A review of Cambrian and Ordovician stratigraphy in New South Wales

We present a comprehensive review of a significant interval spanning 100 million years in the geological history of New South Wales, listing all currently accepted groups, formations and constituent members of Cambrian and Ordovician age. These units are briefly described and placed in their tectonic context, with the most up-to-date biostratigraphic and isotopic age dating assembled to constrain correlations (depicted in 25 representative stratigraphic columns) across orogenic belts and terranes. Rock units previously assigned a Cambrian or Ordovician age, whose names are now obsolete, redundant or are known to be younger, are also discussed or listed in an appendix. The increasingly diverse literature on the Cambrian and Ordovician stratigraphy of the state is reflected in an extensive bibliography. This review is intended to benefit the mineral exploration industry, research workers both locally and overseas, and geological mapping generally by providing a ready reference to Cambrian and Ordovician rocks in NSW. It also indicates where current data are insufficient to resolve precise age determinations and correlations, thereby highlighting those areas that require further work before a complete synthesis of the early Palaeozoic geological history of NSW can be undertaken.