Orogenic lode gold deposits formed within a range of crustal environments over most of the Yilgarn craton from 2640 to 2630 Ma, but there is little evidence 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 isotope, and SHRIMP U-Pb zircon studies define a continent-continent collisional event with a widespread thermal anomaly, probably due to lithospheric delamination at this time. It is proposed that this event was of sufficient scale to drive the giant upper-crustal fluid circulation systems, with lateral and vertical flow at the scale of hundreds and tens of kilometers, respectively, that produced the widespread gold mineralization.

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