ARCHEAN GOLD MINERALIZATION SYNCHRONOUS WITH THE FINAL STAGES OF CRATONIZATION, YILGARN CRATON, WESTERN-AUSTRALIA

Sm-Nd ages of pegmatite dikes that crosscut gold-bearing structures in the southern Yilgarn Craton, Western Australia, provide minimum age c onstraints of 2640 +/- 11 Ma, 2628 +/- 10 Ma, and 2620 +/- 36 Ma for g old mineralization at the Westonia and Nevoria (Yellowdine Terrane) an d Scotia (Norseman Terrane) gold deposits, respectively. Similarly, a post-gold mineralization dike at Westonia has a U-Pb zircon age of 263 7 +/- 8 Ma. These constraints are consistent with, and provide further support for, suggestions that the majority of gold deposits in the Yi lgarn Craton formed during a regionally extensive gold mineralization event at ca, 2630 Ma (i.e., 2630 +/- approximate to 10 Ma). In combina tion with recent geochronological results, these data also provide fur ther evidence that, although mineralization appears to significantly p ostdate the majority of magmatic and metamorphic activity at higher cr ustal levels, widespread thermal reworking of the lower-middle crust, involving partial melting, amphibolite to granulite facies metamorphis m, and lower crustal granitoid intrusion, occurred concurrently with g old mineralization at ca. 2630 Ma, It is probable that the large-scale hydrothermal fluid flow that produced widespread gold deposition was also part of this tectonothermal event, Models developed for other Arc hean terranes whereby gold mineralization postdates formation and crat onization of host granite-greenstone terranes, and is therefore unrela ted to these processes, are not required to explain the timing of the majority of gold deposits in the Yilgarn Craton.