Major orogenic gold episode associated with Cordilleran-style tectonics related to the assembly of Paleoproterozoic Australia

Abstract

New in situ sensitive high-resolution ion-microprobe (SHRIMP) U-Pb analyses of hydrothermal phosphates associated with orogenic gold mineralization in the Paleoproterozoic Ashburton and Pine Creek gold provinces of northern Australia provide ages of ca. 1740 and ca. 1730 Ma, respectively. Argon-argon analyses of gold-related hydrothermal mica from the Tanami gold province of northern Australia provide ages ca. 1730 Ma. It is important to note that late orogenic events across the western half of Australia coincide with gold metallogenesis across this time interval, in several widely separated provinces. Thus, this orogenic gold episode is interpreted to relate to tectonic events during the amalgamation of various continental blocks to form Paleoproterozoic Australia. It is potentially Earth's best-preserved record of orogenic gold formation during a major early Precambrian continental assembly event.