Palaeoproterozoic to Mesoproterozoic Geology of North Queensland

Einasleigh Metamorphics• Psammopelitic gneisses (biotite & calc-silicate types); common mafics; rareleucogneiss (feldspathic psammite?)• Previously correlated with lower part of Etheridge Group – gradationalboundary - may be partly true, but geochemistry and zircons suggestprovenance differences• Upper amphibolite to transitional granulite metamorphism• Age constraints‣ 1700Ma SHRIMP on detrital zircons in leucogneiss (epiclastic sedimentsfrom a felsic igneous source – Black & others, 2005)‣ ~1690Ma SHRIMP on zircons from trondhjemitic gneissic granite‣ ~1675Ma SHRIMP on zircons from amphibolite intruding 1695Ma granitegneiss‣ Detrital ages of both biotite and calc-silicate paragneisses, have beenobtained, but need more interpretation - spread of ages between ~1670 and3240 Ma, with no big groups – some clusters between 1700 and 1900 Ma and2300 and 2600