REMMEL BATHOLITH 347 



ing is much more manifest on the east side of Osoyoos lake than on the 

 west side. 



REMMEL GRANODIORITE BATHOLITH 



Physical and mineralogic characteristics. — There are many principal 

 points of resemblance in composition between the extreme eastern and ex- 

 treme western members of the composite batholith (see figure 2). The 

 staple rock of the Eemmel batholith is also a granodiorite. It is in color 

 a light gray, weathering whitish to a light brownish gray; in grain, 

 medium to rather coarse ; in structure, eugranitic, though often somewhat 

 porphyritic in look, through the development of large, black, lustrous bio- 

 tites. These phenocrysts are sometimes perfectly idiomorphic, and then 

 weather out in hexagonal plates about one centimeter in diameter. This 

 commonest phase of the batholith is essentially composed of brownish 

 green hornblende, biotite, quartz, orthoclase, and andesine which averages 

 Ab 5 An 3 . Titanite is a fairly abundant accessory and is accompanied by 

 apatite and by magnetite, often titaniferous. The specific gravity of this 

 rock varies from 2.721 to 2.775, averaging 2.748. 



Metamorphism. — Here again it is difficult to distinguish in the field 

 any systematic variation of the original rock composition. If such varia- 

 tion ever were important, its discovery is rendered most uncertain through 

 the profound metamorphic changes that have affected the batholith. 

 Here, too, there has been tremendous shearing and crushing. A second- 

 ary gneissic structure has been formed over most of the batholith as ex- 

 posed in the boundary belt. The shearing has been extraordinarily 

 powerful in a north-south zone of the batholith running along the contact 

 with the younger Cathedral batholith (see figure 5). In that zone, 

 which extends westward as far as the Ashnola gabbro, the Eemmel rock 

 has been thoroughly changed from its original condition. 



This "Eastern phase" of the Eemmel is now remarkably banded. The 

 broader bands are more or less massive biotite gneiss rich in oligoclase 

 (AbeAnJ, or orthoclase-bearing biotite quartz diorite gneiss. The color 

 of these rocks is light gray, weathering white or light brown. Hornblende 

 and titanite completely fail ; apatite is accessory, but in small amount. A 

 few reddish garnets are occasionally developed. There is seldom any in- 

 dication of straining or crushing of the minerals constituting these bands. 

 Microscopic study leaves the impression that the material of the bands has 

 been wholly recrystallized. The specific gravity averages 2.651, and is 

 thus considerably lower than in the normal granodiorite. 



Alternating with the broad bands are very numerous dark green-gray, 

 highly foliated zones of mica-gneiss and mica-schist, both very rich in bio- 



