Middle-Late Devonian nascent back arc formation, southern New England Orogen, NSW, Australia

Dolerite dyke swarms are common in Devonian sequences of the Tamworth Belt, southern New England Orogen but have not been studied in detail. We present new geochemical and LA-ICP-MS U-Pb zircon data obtained from dolerites in the Glenrock Station area, NSW. Our study shows that most dolerites have tholeiitic to transitional basaltic compositions, a few boninitic features. Most have chondrite normalised patterns that exhibit slight or no LREE enrichment and PM normalised patterns showing varying degrees of Nb depletion and Th enrichment.