Occurrence and petrogenesis of diverse S-type granites in an extensional tectonic setting: a case study from the Wongwibinda Complex, eastern Australia

The high-temperature–low-pressure (HTLP) Wongwibinda Metamorphic Complex (WMC) hosts four distinct types of early Permian S-type granitoids belonging, or related, to the Hillgrove Supersuite. We use field relationships, age data and petrogenetic modelling to determine the petrogenesis of these granitoid types. Biotite-only bearing granitoids are the most voluminous (∼50% of the WMC area). A newly characterised second type (via the Wongwibinda Shear Zone. Small volumes of two-mica Wongwibinda monzogranite type granitoids are commonly associated with HTLP metamorphism in extensional tectonic settings. Four granitoid types are recognised within the WMC. One is newly named and described. Petrogenetic modelling and isotope data indicate that three are pure S-types formed from local metasedimentary rocks. The most voluminous plutons are concluded to be a mix of S-type melts with minor mafic magma.