Sm‐Nd ages of the Arunta, Tennant creek, and Georgetown inliers of Northern Australia

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Abstract
A reconnaissance Sm‐Nd study has been made on three areas of Precambrian rocks in northern Australia. This reveals that the Arunta Inlier was originally formed at 1980 ± 190 Ma. Basement rocks below the Warramunga Group in the Tennant Creek area are conservatively dated at about 2300 Ma, and with reasonable assumptions, may be assumed to be uppermost Archaean. Early Georgetown Inlier rocks were possibly derived ∼ 2500 Ma ago from a depleted mantle source with 6Nd = +4±0.5. The provenance of at least some Georgetown Inlier metasediments appears to be only marginally older. These results suggest that crust of age 2000–2500 Ma may be more widespread in central and eastern Australia than was previously realised.