Basalts and silcretes on the coast near Ulladulla,southern New South Wales |
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Authors: | R. W. Young Ian McDougall |
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Affiliation: | 1. Department of Geography , University of Wollongong , P.O. Box 1144, Wollongong, N.S.W., 5200;2. Research School of Earth Sciences , Australian National University , P.O. Box 4, Canberra, A.C.T., 2600 |
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Abstract: | Silcretes on the N.S.W. coast near Ulladulla have long been attributed to. a sub‐basaltic origin, but field evidence is at odds with all variations of the sub‐basaltic hypothesis, and one site shows good evidence that the basalt post‐dates the silcrete. K‐Ar ages averaging 29.7 ± 0.5 Ma from the basalts provide a minimum age for silcrete development in this area. Furthermore, the K‐Ar dates, together with evidence for an erosional rather than tectonic origin of the coastal lowland, demonstrate that the adjacent tablelands reached their present elevation prior to the mid‐Oligocene. |
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Keywords: | Basalt silcrete uplift of Southern Highlands (N.S.W.) K‐Ar ages |
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