Papers Published

1. Horstwood, Matthew S.A. and Nesbitt, Robert W. and Noble, Stephen R. and Wilson, James F., U-Pb zircon evidence for an extensive early Archean craton in Zimbabwe: A reassessment of the timing of craton formation, stabilization, and growth, Geology, vol. 27 no. 8 (1999), pp. 707 - 710 [0091-7613(1999)027<0707:UPZEFA>2.3.CO;2] .
   (last updated on 2007/04/09)

   Abstract:
   U-Pb single-zircon analyses provide direct evidence for an enlarged early Archean craton forming the core to the present Zimbabwe craton. Virtually identical dates from the south-central Tokwe segment (3455±2 Ma) and Midlands (3456±6 Ma) parts of the craton strongly suggest their synchronous formation, during an event that formed a single early cratonic nucleus which we propose to call the `Sebakwe protocraton.' This is considered to underlie most of the current Zimbabwe craton. Parts of the craton are at least 3565±21 Ma, a rock age reported here that represents the oldest rock dated from Zimbabwe. A ca. 3350 Ma relatively undeformed and unmetamorphosed intrusive granitic phase constrains the timing of the high-grade metamorphism and the stabilization of the protocraton. Comparison with published Re-Os data for the Zimbabwe craton strongly indicates a depleted subcontinental lithospheric mantle underlying the entire Sebakwe protocraton. Subsequent intrusive and volcanic activity from 3.0 to 2.6 Ga represents a second major period of magma genesis and crustal formation within which the predominant rocks of the exposed Zimbabwe craton were generated.