454 



DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



In the Norm classification the rock enters the sodipotassic subrang, beeme- 

 rose, of the peralkalic rang, miaskase, in the persalane order, russare. In the 

 older classification it is a hornblende (biotite) nephelite syenite. Partly on 

 account of the fine grain of this rock its actual mineralogical composition or 

 mode could not be determined by the Rosiwal method. 



Summary. — Table XXVIII facilitates a rapid review of the chemical 

 variety of the Kruger alkaline body. Col. 4 shows the average of all three 

 analyses and is doubtless not far from the average for the whole body. This 

 average recalls the analysis of a typical leucite syenite and also that of the 

 borolanite described by Home and Teall.§ In' mineralogical composition, how- 

 ever, the average rock of the body would more closely approximate the rnalig- 

 nites of Ontario. It seems best, therefore, to consider the average rock of the 

 body as a malignite passing into nephelite syenite. Differentiation of the corres- 

 ponding magma has yielded true nephelite syenite of granitic structure; coarse 

 augite and biotite syenites of porphyritic structure; and various types of 

 malignite, in which, however, the potash is in distinct excess over the soda. In 

 the latter respect the Kruger body is in contrast with the average malignitic 

 type of Ontario. 



Table XXVIII. 



Analyses of malignites and nephelite syenites. 





1 



2 



3 



4 



5 



6 



7 



SiO. 



50-43 



52 53 



55 11 



52"71 



47-85 



51-88 



51-38 



TiO., 



02 



•07 



•48 



■49 





■33 



12 



ALO, 



15-83 



19 05 



21-28 



IS -72 



13 24 



14 13 



15-88 





611 



4-77 



2-64 



431 



274 



6"45 



1-48 



FeO 



3 04 



210 



129 



214 



265 



■94 



437 



MnO 



11 

 3-38 



13 

 1-99 



•08 

 ■59 



•11 

 1-99 









MgO 



5-68 



3'44 



4-43 



CaO, 



7-99 



575 



2-82 



5-52 



14 36 



10-81 



8-62 



SrO 





■19 



09 



4 03 













BaO 



312 













Na„G 



624 



4-46 



3 72 



672 



7-57 



K.,0 



6-86 



7-30 



836 



742 



5-25 



457 



420 



H„0- 



■29 



13 



14 



18 



1 



•18 





HoOh- 



1-20 



149 



•58 



109 



- 2 W 4 



•42 



PoO B 



■42 



■28 



•27 



■32 



2-42 



•96 



■98 



co„ 



•07 



99-83 



'27 



•08 



•14 

















• 



100-17 



99 96 



99-60 



100 -C5 



100-41 



99 45 



Sp. gr 



2-849 



2 719 



2 666 





2-879 



2-88 





1. Augite-biotite malignite, Kruger mountain. 



2. Biotite-melanite-nephelite syenite, Kruger mountain. 



3. Hornblende-nephelite syenite, Kruger mountain. 



4. Average of 1, 2, and 3. 



5. Nephelite-pyroxene malignite, Poobah lake, Ontario. 



6. Garnet-pyroxene malignite, Poobah lake, Ontario. 



7. Amphibole malignite (garnet-free), Poobah lake, Ontario. 



STrans. Eoy. Academy, Edinburgh, Vol. 37, 1892, p. 163. 



