Late Archean collision and delamination in the southwest Yilgarn craton: The driving force for Archean orogenic lode gold mineralization?

Orogenic lode gold deposits formed within a range of crustal environments o ver most of the Yilgarn craton from 2640 to 2630 Ma, but there is little ev idence for a causative widespread tectonomagmatic event at this time in the most highly mineralized greenstone terranes. In the exposed deeper crustal levels of the southwest Yilgarn craton, however, field, geochemical, Pb is otope, and SHRIMP U-Pb zircon studies define a continent-continent collisio nal event with a widespread thermal anomaly, probably due to lithospheric d elamination at this time. It is proposed that this event was of sufficient scale to drive the giant upper-crustal fluid circulation systems, with late ral and vertical flow at the scale of hundreds and tens of kilometers, resp ectively, that produced the widespread gold mineralization.