THE METAMORPH1C ROCKS OF ADELIE LAND. STILLWELL. 



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Relic crystals of quartz, felspar, magnetite, and lenticles of quartz form the pseudo- 

 porphyroblasts around which the schistose ground mass bends. Some of the larger 

 crystals of felspar are sericitised, while others are very fine granulitic aggregates of 

 secondary felspar. The ground mass consists of small flakes of brown biotite, white 

 muscovite, granular epidote, quartz, clear secondary felspar, prisms of tourmaline, 

 apatite and zircon, magnetite and pyrite. 



The biotite and muscovite are frequently intergrown. Occasionally there are 

 much larger crystals of muscovite, and these may be bent. All the small biotite flakes 

 are parallel, so that as the stage is rotated they all occupy the dark position at the same 

 time. The pleochroism is strong, and consequently the section looks dense in one 

 position but quite thin in the other position. In the latter position the rarer tourmaline 

 prisms are in their dark blue position and can readily be picked up. There is a con- 

 siderable amount of fine granular epidote among the fine material and, like the muscovite, 

 larger porphyroblasts occasionally appear. Clear secondary felspar has been detected 

 among the fine quartz but is much less abundant than the quartz. Iron ore is abundant, 

 and numerous small cubes of pyrite have been seen. Colourless crystals of apatite are 

 present, and also rounded crystals with high polarisation colours and high refractive 

 index like zircon. 



The rock can be named phyllite. 



As far as can be made out the crystalloblastic order is Tourmaline-magnetite, 

 pyrite-biotite, muscovite-epidote-felspar and quartz. 



