Discussion: Structural and stratigraphic problems of the Argylla Formation near Mary Kathleen,Queensland |
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| Authors: | G M Derrick I H Wilson |
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| Institution: | 1. Bureau of Mineral Resources , P.O. Box 378, Canberra City, A.C.T., 2601;2. Geological Survey of Queensland , P.O. Box 194, Brisbane, Qld, 4001 |
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| Abstract: | Circumstantial evidence indicates that Gaussberg, an isolated, 370 m high volcanic cone on the Antarctic coast at 57°S, 89°E, is the product of subglacial eruption. The vesicular, highly potassic leucitite, of which Gaussberg is composed, has been dated by K‐Ar and fission‐track methods, the former being applied to leucite concentrates, the latter to glassy leucitite from the ropy‐textured, outer rind of a pillow‐like structure. The K‐Ar geochronology yields an average date of 56 000 ± 5000 years, jwhich is interpreted as defining the time of Gaussberg's formation. The fission‐track work yields a less precise date, which supports the K‐Ar age estimate. These new age determinations indicate that previously published K‐Ar age determinations of 20 Ma and 9 Ma for Gaussberg should be rejected. |
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| Keywords: | Gaussberg Antarctica volcanic cone leucitite geochronology |
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