Correlation of the Archaean Mallina ‐ Whim Creek Basin: Implications for base‐metal potential of the central part of the Pilbara granite‐greenstone terrane

Abstract

The ca 3000 Ma Whim Creek Belt forms part of the central granite‐greenstone terrane of the Archaean Pilbara Craton, northwestern Western Australia, and hosts significant Cu–Zn ± Pb deposits. Lithostratigraphic studies and geochronological results suggest that the volcano‐sedimentary rocks of this belt either correlate directly with, or immediately underlie, the sedimentary rocks of the adjacent and regionally extensive Mallina Basin (i.e. a Mallina ‐ Whim Creek Basin). Consequently, the Mallina Basin should also be considered highly prospective for Cu–Zn ± Pb deposits. In the Mallina Basin, numerous minor base‐metal deposits have similarities to deposits of the Whim Creek Belt, which strongly supports this view. Lead‐isotope data tentatively suggest that mineralisation in the Whim Creek Belt relates to two separate events that can be correlated with felsic magmatism throughout the Mallina ‐ Whim Creek Basin. It is not yet possible to place unequivocal constraints on the genesis of the base‐metal deposits of the Mallina ‐ Whim Creek Basin as these mineral deposits have features that are consistent with both a Cobar‐type syntectonic model or a volcanic‐hosted massive sulfide model. Comparisons of deposits throughout the Mallina ‐ Whim Creek Basin reveal a number of empirical characteristics that may be useful in developing exploration models, including: (i) a close spatial association with high‐Mg basalts; (ii) an association with coarse clastic rocks of the Cistern Formation and Constantine Sandstone; and (iii) an association with anticlinal closures and/or growth and tectonic faults.