REPORT OF THE GRIEF ASTRONOMER 



539 



SESSIONAL PAPER No. 25a 



Table XXXIII. — Analyses of grwnodiorites. 



— 



1 



Phase 1 of Chilli- 

 wack batholith. 



2 



Phase2ofChilli- 

 wack batholith. 



3 



Average 

 of Two Phases. 



4 



Average 

 of Twelve Types. 



SiO„ 



TiO., 



60 



17 



1 

 3 



3 

 6 

 3 



1 



36 

 70 

 23 

 93 



74 

 14 

 66 

 07 

 58 

 74 

 06 

 55 

 11 

 OS 



71 



14 

 1 

 1 



1 

 2 

 4 

 2 



41 

 34 

 38 

 33 

 17 

 04 

 13 

 51 

 12 

 97 

 09 

 30 

 13 

 19 



65 



15 



1 

 2 



2 

 4 

 3 



2 



88 

 52 

 80 

 63 

 46 

 09 

 40 

 29 

 85 

 35 

 08 

 43 

 12 



in 



65-10 



54 



ALO., 



Fe,,0. 



15-82 



164 



FeO 



266 



MnO 



05 



MgO 



CaO 



217 

 4'66 



Xa.,0 



3-82 



K„0 



2'29 



H.,0, at HOT! 



•16 



H.,0, above 



p.;o 5 



110°C 



93 

 •16 

















99 "95 



100 04 



loo-oo 



100-00 



The third major phase of the batholith is probably the most abundant of 

 the three. ATacroscopically it is almost indistinguishable from the phase first 

 described. The microscope shows, however, that orthoclase is here an essential 

 constituent. In the order of decreasing abundance the essentials are plagioclase. 

 near Ab 4 An 3 ; quartz ; orthoclase ; hornblende ; biotite. The two f ernic minerals 

 are in about equal amount. In optical properties all these minerals are identical 

 with those of the first phase. The accessories' are also the same as there but a 

 few grains of allanite are associated. 



This phase occurs at many points in the batholith. The type specimen was 

 collected at the mouth of Depot creek on the east side of Chilliwack lake, and 

 thus in the heart of the batholith. The specific gravity of this specimen is 2-678. 

 It is a normal granodiorite. It has not been analyzed, but its analysis would 

 probably be close to the mean of the two analyses of the other phases (column 3). 



We may conclude that the average rock of this batholith is a true grano- 

 diorite tending towards the composition of a quartz diorite. 



The specific gravities of six fresh, type specimens from the batholith vary 

 from 2-626 to 2-757, averaging 2-693. 



Xodular basic inclusions occur at various points in the mass. They are 

 seldom very numerous and, so far as observed, never of large size; diameters 

 exceeding 10 cm. are very uncommon. All of these dark-coloured nodules are 

 probably indigenous bodies. They are of two kinds, both of which occur in the 

 staple granodiorite phase. 



The one kind has some similarity to the Slesse diorite. It is a rather dark 

 greenish-gray, fine-grained rock, composed of labradorite, green hornblende, and 

 les3 important biotite as the chief essentials, with magnetite, apatite, titanite, 

 and zircon, a little quartz, and a very little orthoclase as accessories. The struc- 



