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Buchia Buttress Formation

Description

A succession at least 400 m in thickness dominated by volcanic breccias, tuffs, volcaniclastic rocks, accompanied by interbedded coarse grained sandstones and pebble conglometrates. Outcrops at Buchia Buttress, Sheldon Glacier area and Turner Glacier. The sandstones are locally fossiliferous (ammonite, bivalve, plant material) suggesting a Tithonian age (Thomson 1972)1. An age confirmed by U-Pb (zircon) dating of an interbedded crystal tuff at Buchia Buttress (149.5 ± 1.6 Ma; Riley et al., 2012)2. The Buchia Buttress Formation is overlain by basaltic andesites of the Bond Nunatak Formation.

Age

Late Jurassic (149.5 ±1.6 Ma)

Map Reference

Riley, T. R., Flowerdew, M. J. & Haselwimmer, C. E. Geological Map of Adelaide Island, Graham Land (1:200 000 scale). Sheet 2, (British Antarctic Survey, 2011). Available here.

References

  1. Thomson, M. R. A. New discoveries of fossils in the Upper Jurassic volcanic group of Adelaide Island. Br. Antarct. Surv. Bull. 30, 95–101 (1972). ↩

  2. Riley, T. R., Flowerdew, M. J. & Whitehouse, M. J. Chrono-and lithostratigraphy of a Mesozoic–Tertiary fore-to intra-arc basin: Adelaide Island, Antarctic Peninsula. Geol. Mag. 149, 768–782 (2012). ↩