Bulletin No. 32 (5) - 2003: Metallogenic studies of the Broken Hill and Euriowie Blocks, New South Wales, Mineral Deposits of the Northern Broken Hill Block.

Abstract

The Broken Hill Block in western New South Wales is host to one of the world's great lead-zinc-silver deposits. This report is the fifth in a series of descriptions of the metallogenesis of the Broken Hill and adjacent Eurowie Blocks. The Broken Hill Block North 1:50 000 metallogenic map area contains a wide variety of mineral deposit types, and many significant prospects. Nearly all of the 1300 mineral occurrences shown on the map are hosted by the Early Proterozoic Willyama Supergroup, a metasedimentary sequence, with lesser metamorphosed acid and basic magmatic rocks. The northern part of the Broken Hill Block includes the areas of lowest metamorphic grade, permitting a better understanding of the geology, rock types and some mineral deposit types. Stratiform deposits include Broken Hill type, Ettlewood type, Corruga type, Sisters type, and Great Eastern type deposits. Broken Hill type deposits consist of lead-zinc sulphide concentrations with associated granular quartz-gahnite/garnet "lode horizons". They occur in clusters, with small, but significant production from the Allendale and Southern Cross-Parnell mines. Drilling at the Stephens Trig and Peppertree prospects obtained some of the best lead-zinc intersections found outside the Broken Hill Main Lode. Ettlewood type deposits are confined to the Ettlewood Calc-Silicate Member. This type contains significant amounts of scheelite, sphalerite and minor galena, but the known calc-silicate bodies are too small to host an orebody. Corruga type deposits are hosted by Broken Hill Group calc-silicate rocks with an irregular texture, and contain base metal sulphides and/or scheelite. In the Broken Hill Block North area, they have shown limited prospectivity, but may help delineate Broken Hill type ore-forming systems.

Reference

Stevens B.P.J., Barnes RG., Raphael N.M. & Burton G.R 2003. Metallogenic studies of the Broken Hill and Euriowie Blocks, New South Wales. 5. Mineral deposits of the northern Broken Hill Block. Geological Survey of New South Wales, Bulletin 32(5), xii + 244 pp.