222 



PETROLOGY OF ROCK COLLECTIONS 



Analysis of Augite-Biotite-Kersantite by Dr. G. T. Prior 

 Si0 2 50-71 



Ti0 2 



A1 2 3 



Fe 2 3 



FeO 



MnO 



CaO 



MgO 



Na 2 



K 2 



P 2 5 



H 2 + 



H 2 0- 



C0 2 



2-71 



17 08 

 1-38 

 8-71 

 0-09 

 5-75 

 3-63 

 3-82 

 3-63 

 0-57 

 1-75 

 016 



trace 



99-99 



Dr. Prior describes, from various occurrences in the Ferrar Glacier region, lampro- 

 phyric rocks related to banakite. These contain basaltic hornblende both porphyritic 

 and amongst the finer material of the base, but are specially distinguished as containing 

 porphyritic orthoclases. The field occurrences and the consanguinity, as indicated by 

 the analysis, suggest that these banakites are also a further variation of the one series. 



Analysis (by Dr. Prior) of Lamprophyric Dyke related to Banakite from 



the Ferrar Glacier Area 



100-00 



A lamprophyric dyke met with at Cape Ross was observed to be shot through with 

 abundance of idiomorphic hornblende needles. Unfortunately the specimens of this 

 rock were left at the Depot Island cache.* 



Amongst Priestley's collection from the Dry Valley moraines is a nice example of 

 a vein of this lamprophyre intersecting a pinkish granite-porphyry. Both of these 

 rock types correspond with those at Cape Irizar. The lamprophyre contains pheno- 

 crysts of porphyritic andesine, often zoned, and abundance of idiomorphic twinned 

 basaltic hornblende rods. Kaolinisation has attacked the interior of the felspars but 

 there generally remains a clear border zone. The fine material of the base consists of 

 tiny particles of plagioclase, orthoclase, quartz, and iron ores. 



* See description by L. A. Cotton in appended Notes. 



