THE 
HMeOURNAL OF GEOLOGY 
Poe BIGOAKY—-NMARCH, 1972 
AN EXPERIMENTAL CONTRIBUTION TO THE QUESTION 
OF THE DEPTH OF THE ZONE OF FLOW 
IN THE EARTH’S CRUST 
FRANK D. ADAMS 
McGill University, Montreal 
INTRODUCTION 
In connection with an experimental study of the Flow of Rocks, 
on which the author has been for some time engaged and in which 
he has been assisted by grants from the Carnegie Institute of 
Washington, the question of the depth of the Zone of Flow beneath 
the surface of the earth has naturally presented itself. This sub- 
ject has an interest and importance, not only as bearing upon many 
problems in geology, but also on one question at least of direct 
importance in mining, namely, that of the depth to which mineral- 
bearing fissures may extend in the earth’s crust. 
That the outer portion of the earth’s crust was susceptible of 
subdivision into a Zone of Fracture and a Zone of Flow was set 
forth by Professor Heim in his great work Untersuchungen iiber den 
Mechanismus der Gebirgsbildung, and was based upon the data 
which he had obtained from his life-long studies in the Alps... In 
this epoch-making work Heim states that as the result of his obser- 
vations in the Alps he concludes that the upper surface of the Zone 
t Albert Heim, Untersuchungen tiber den Mechanismus der Gebirgsbildung, Basel, 
1878, Bd. II, 92. 
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