McMurdo Ice Shelf, Antarctica

Representative lithologies of morainic debris

The debris represented here comprises samples of the sea floor. It includes both local late Cenozoic volcanic material from adjacent Minna Bluff and also far-travelled material carried by a grounded glacier in much earlier times. The latter mainly comprises granite and metamorphic rocks of Early Palaeozoic age, with minor amounts of Late Palaeozoic Beacon Sandstone and possibly Eocene conglomerate. This set illustrates relatively fresh clasts of local and distal origin, including lithologies from the Transantarctic Mountains, mostly showing signs of transport at the bed of a grounded glacier.

Representative lithologies of morainic debris
Coarse-grained sandstone with faceted surface (from the Transantarctic Mountains).
Representative lithologies of morainic debris
Coarse-grained sandstone with striations, indicative of former basal glacial transport (from the Transantarctic Mountains).
Representative lithologies of morainic debris
Stratified sandstone with cross-bedding from the Beacon Supergroup (from the Transantarctic Mountains).
Representative lithologies of morainic debris
Sandy conglomerate of possible Eocene age (local).
Representative lithologies of morainic debris
Agglomerate from the McMurdo Volcanics (local).
Representative lithologies of morainic debris
Orange-weathered tephra from the McMurdo Volcanics (local).
Representative lithologies of morainic debris
Pale-weathered vesicular basalt (probably local).
Representative lithologies of morainic debris
Red granite (from the Transantarctic Mountains).
Representative lithologies of morainic debris
Fine-grained white granite (from the Transantarctic Mountains).
Representative lithologies of morainic debris
Close-up of white granite with xeonolith (from the Transantarctic Mountains).
Representative lithologies of morainic debris
Granite-gneiss with xenolith (from the Transantarctic Mountains).
Representative lithologies of morainic debris
Grey-white banded gneiss (from the Transantarctic Mountains).
Photos Michael Hambrey, November and December 2010.