PARTIAL CONVECTIVE OVERTURN OF ARCHEAN CRUST IN THE EAST PILBARA CRATON, WESTERN-AUSTRALIA - DRIVING MECHANISMS AND TECTONIC IMPLICATIONS

Strain varies systematically from weakly-developed, outward-dipping: S -tectonites in the similar to 3320-3310 +/- 10 Ma Mount Edgar Batholit h to intensely deformed, subvertical, L-tectonites in greenstones of t he Warrawoona syncline. A consistent 'greenstone-down/batholith-up' se nse of shear is recorded in batholithic domal margins and adjacent hig h-grade supracrustal rims: lineations converge to a central zone of su bvertical extension (zone of sinking) along the synclinal axis. AT dom al margins, early kinematic granitoid sheets and 'intrusive diatexites ' are subconcordant to a well-developed, dome-parallel schistosity, bu t late- to post kinematic intrusives are discordant, high-level pluton s. All granitoids are the same age, within analytical error.