. British Antarctic expedition, 1907-9, under the command of Shackleton : reports on the scientific investigations ; geology. S*^^^.^«^^^<;,(^;^^^^. inlet Crack in 6e3 ice with slabs of Sea ice fyrced up by pressure. Fig. 17. View of coast looking to at point 8 miles south of Drygalski Ice Barrier Tongue The next sketch (Fig. 18) shows Cape Irizar itself, about 600 feet high, foi-medof biotite allanite granite peeping out in places from under the ice calotte. The ciader rIce- Basle Dykes cutting porphyritic granite. I s a 6Red Porphyritic Cranite. Basic Dyke Fig. 18. DETAILS OF
. British Antarctic expedition, 1907-9, under the command of Shackleton : reports on the scientific investigations ; geology. S*^^^.^«^^^<;,(^;^^^^. inlet Crack in 6e3 ice with slabs of Sea ice fyrced up by pressure. Fig. 17. View of coast looking to at point 8 miles south of Drygalski Ice Barrier Tongue The next sketch (Fig. 18) shows Cape Irizar itself, about 600 feet high, foi-medof biotite allanite granite peeping out in places from under the ice calotte. The ciader rIce- Basle Dykes cutting porphyritic granite. I s a 6Red Porphyritic Cranite. Basic Dyke Fig. 18. DETAILS OF CAPE IRIZAR AND ITS ICE CALOTTEThe section below is taken across the basic djkes shown in the upper sketch granite is intersected by an interesting group of kersantite dykes, described byDr. Mawson in his chapter relating to the petrology of this area. On either side of the dykes, for a distance of a few feet, the felspars of thegranite were deeply reddened as the result of contact metamorphism. This granitewas also traversed by acid dykes, apparently aplitic in character, and of earlierorigin than the basic dykes. These acid dykes are lenticular in character. 66 GLACIOLOGY The granite is traversed by small veins of a dark mineral which is probablybiotite or schorl. The granite showed evidence of having been very heavilyglaciated, showing that recently there was a great thickness of ice over its the summit were numerous erratics of gabbro, dolerite, hornblendic dyke rocks,sphene-granite, pinkish-grey felsites, &a
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