392 DEPARTMENT OF THE INTERIOR 



2 GEORGE V, A. 1912 



Termier denies the efficiency of dynamic metamorphism, in the accepted mean- 

 ing of that term, in the development of these rocks. After forcibly presenting 

 his arguments for the case of the Alps, Termier states his conviction that the 

 mineralogical changes suffered hy the Alpine sediments are due only to thermal 

 metamorphism aided by magmatic emanations. One must believe, however, 

 that he goes too far in holding that dynamic metamorphism ' does not exist.'§ 



The petrographic study of the Anarchist series seems to show facts that 

 do not substantiate his view. It will scarcely explain the striking uniformity 

 of the phyllites throughout the greater part of their area in the Boundary belt. 

 Their only serious variation from the normal occurs in a narrow contact zone 

 about the O-soyoos batholith. The batholithic magma has there produced 

 relatively large-foiled muscovite along with tourmaline and other familiar 

 contact products — all minerals which are regularly absent in the twenty-mile 

 belt from Osoyoos lake eastward. There is, indeed, a decided difference of 

 quality between the obvious contact metamorphism and that change which has 

 affected the main body of old argillite so drastically. The yet more ancient 

 argillites of the Eocky Mountain Geosynclinal were completely recrystallized 

 by the action of their own fluids acting under conditions of dead weight and 

 deep burial. In that case igneous intrusions are extremely rare at the present 

 surface, and there is no indication that they have ever affected the Cambrian 

 rocks or in many cases come within several miles of them. If, then, static 

 metamorphism can cause the more or less perfect recrystallization of argillace- 

 ous rocks, it seems most reasonable to believe that similar rocks, also deeply 

 buried, charged with fluids and certainly heated during orogenic movements of 

 great intensity, would, in the process of time, crystallize so as to form phyllites 

 or mica schists. 



A complete discussion of the problem would be out of place in this chapter, 

 but with this note the writer wishes to record his belief in the soundness of the 

 time-honoured conception of dynamic metamorphism. 



Bock Creek Plutonic Bocks. 



Near the forks of Eock creek a small area of plutonic rocks occurs between 

 the Paleozoic sediments of the Anarchist series and the Tertiary lavas north of 

 the creek. The plutonics include granodiorite, basic diorite, and serpentinized 

 dunite. All of these cut the Paleozoics. The diorite is cut by the granodiorite 

 which has furnished arkose material to the Kettle Eiver Oligocene formation. 

 Both granodiorite and diorite are therefore of pre-Oligocene age and are 

 probably post-Carboniferous. The dunite has been vigorously crushed and 

 sheared, indicating that it also dates from pre-Oligocene time. 



Diorite. — The diorite is a dark green, medium-grained rock. It is greatly 

 altered, but the original essential constituents seem to be biotite, green 

 hornblende, and plagioclase of medium acidity. Magnetite, apatite, titanite, 



§ Cf. P. Termier. Congres geologique international, Compte Rendu, Ninth session, 

 Vienna. 1903. pp. 571-586. 



