BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 34, pp. 431-448 SEPTEMBER 30. 1923 



FUSIOX OF SEDIMENTAEY ROCKS IN DEILL-HOLES ^ 



BY X. L. BOWEX AXD M. AUROUSSEAU 



(Presented hefor^e the Society December 30, 1922) 



CONTENTS 



1 'a ';;•(> 



Introduction 431 



Microscopic characters of the core material 433 



Chemical character of the core material 435 



Chemical effects of fusion 436 



Temperature of fusion 437 



Changes effected in the steel of the core barrel 438 



Production of heat by friction 439 



Core from "Meyer 6*' well of the Union Oil Company 440 



Systematic position of the fused samples 442 



General considerations regarding the fusibility of cores 444 



Refusion of sediments as a factor in magma genesis. 444 



Summary 447 



Discussion 447 



IXTRODUCTIOX 



In drilling for oil the taking of core samples of the beds penetrated is 

 becoming a common practice. With the rotary drill the rock cuttings 

 are ordinarily swept out by a vigorous forced circulation of sludge in the 

 hole^ but it has been found possible in many cases to modify the pro- 

 cedure in such a way that a core of moderate length can be obtained. 

 The usual bit is dispensed with and a lengi;h of ordinary drill pipe with 

 teeth cut at the end is substituted. This is rotated at the bottom of the 

 hole, and under favorable circumstances it cuts through the rock and 

 furnishes a cylindrical core. The presence of the core prevents the circu- 

 lation of water to the bottom of the hole; indeed, a wooden plug is 

 sometimes inserted in the top of the core barrel to guarantee this condi- 

 tion. With the free circulation of water thus cut off, the heat produced 

 by the friction of boring may be sufficiently localized to raise the temper- 

 ature of the rock very considerably ; in fact, it is not uncommon to o])tain 



* Manuscript received by the Secretary of the Society B'ebruary 15, 1923. 



(431) 



