Me Sr p 
' 
NN 
; j 
ät Ra 
- 
vp 
La 
RE Re rd or a RS Sa fr in AGE 
Ko 
Översikt av Finska Vetenskaps-Societetens Förhandlingar. 
Bd. LXIII. 1920—1921. Avd. A. N:o 1. 
On the Igneous Rocks of Sviatoy Noss 
in Transbaikalia 
by 
PENTTI ESKOLA. 
Geological Synopsis of Sviatoy Noss. 
The vast mountainous area of crystalline rocks all around 
Lake Baikal represents an old peneplain, elevated and sub- 
jected to erosion at different geological times. Deep-seated 
igneous and metamorphic rocks and their mixtures were 
thus laid bare. There are, in many parts of this region, 
evidences of an unconformity, i. e. sediments and volcanic 
rocks have been deposited on the denuded roots of ancient 
mountain chains composed of injected ecrystalline schists 
and eruptives. The newly formed supercrustal rocks also 
have undergone metamorphism, but later denudation has 
not been great enough to reach such deep levels where 
pressed down supercrustal rocks may be injected with 
 granitic masses and transformed into migmatites as the older 
rocks. Their metamorphic habit is therefore of another 
character, bearing evidence of folding at comparatively 
shallow depths. Russian geologists have designated this divi- 
sion of rocks as the metamorphic suite and the 
older deep- metamorphic complex of the Transbaikalian 
VE fölneld as the erystalline. suite It is probable, 
2 Ke though not exactly proven, that the latter is of early paleo- 
i. — zoic age. The »crystalline suite» should be of pre-Cambrian 
— origin. 
