BULLETIN OF THE GEOLOGICAL SOCIETY OFAMERICA 

 Vol. 22, pp. 103-122 March 31, 19ii 



ORIGIN OF THE THERMAL WATERS IN THE YELLOWSTONE 

 NATIONAL PARK ^ 



ANNUAL ADDRESS OF THE PRESIDENT^ ARNOLD HAGUE 



{Read before the Society December 21 , 1910) 



CONTENTS 



Page 



Introduction 103 



Eocene igneous rocks 104 



Miocene igneous rocks and thermal waters 106 



Pliocene igneous rocks and thermal waters 107 



Duration of thermal activity 108 



Climatic conditions 109 



Physical structure of rhyolite ^ 110 



Mineral and chemical composition of rhyolite 112 



Classification and composition of thermal springs 114 



Gases from thermal springs 117 



Development of springs and geysers 118 



Radioactivity of thermal waters ]21 



Summary ♦ 122 



Introduction 



From the earliest days of systematic geological research thermal springs 

 have been a frequent subject of investigations by students of natural phe- 

 nomena. From time to time numerous contributions to scientific litera- 

 ture bearing on the nature of hot springs, partly descriptive and in part 

 theoretical, have been presented to learned societies. Nearly all regions 

 where such waters issue from the ground on an imposing scale appear to 

 have been at one time or another scenes of eruptive energy. In so many 

 instances has this been shown to be the case that thermal activity and 

 volcanic manifestations have come to be regarded as associated phe- 

 nomena. It by no means follows, however, that the original source of all 

 these waters was, geologically speaking, deep-seated, and by a large school 

 of geologists it has never been so regarded. In recent years the results of 

 several suggestive researches have been published, in which the position 



1 Manuscript received by tlie Secretary of the Society January 17, 1911. 



(103) 



