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Victoria University Antarctic Research Expedition Science and Logistics Reports 1993-94: VUWAE 38

Pivot Member

Pivot Member

The Pivot Member contains fine-grain sedimentary rocks that in places have been extensively altered to Fe-Ti minerals by hydrothermal fluids related to the emplacement of dikes and sills of the Ferrar Dolerite (Woolfe et al., submitted). Preliminary studies (Woolfe et al., submitted) of the mineralisation suggest that the mechanisms in this type of alteration may be relevant to mineralisation styles in economic deposits worldwide. Two important discoveries related to the Fe-Ti alteration were made on the expedition.

Reconnaissance of the Platform Spur area revealed that fine-grained deposits of the Terra Cotta Siltstone appeared to be altered by Fe-Ti mineralisation. Thus, the mineralisation may be more widespread stratigraphically that previously thought. The site was sampled and the rocks will be analysed by Woolfe.

Woolfe et al. (1989) speculated from observations at a distance, that altered Pivot Member sediments may crop out along the southern end of Sickle Ridge. Close inspection by helicopter and from ground observations on the lower part of the fine-grained sediments at Sickle Ridge revealed that they are not extensively altered by the intrusive Ferrar Dolerite. Thus, all occurrences of the Pivot Member are not significantly altered by Fe-Ti mineralisation.