UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 10, No. 3, pp. 25-37, 10 text-figures IssueO^t^f^JV^} 



— f& 



W OCT 2 1 1916 * 



THE OCCURRENCE OF ORE ON THJT-fcB^ 

 STONE SIDE OF GARNET ZONES* 



BY 



JOSEPH B. UMPLEBY 



CONTENTS 



PAGE 



Introduction 25 



Statement of Thesis 26 



Examples 26 



Washington Camp, Arizona 26 



Silverbell, Arizona 27 



Seven Devils, Idaho 28 



Velardefia, Mexico 20 



Dolores Mine, Mexico 31 



Mackay, Idaho 33 



Whitehorse Copper Belt, Yukon 33 



Interpretation 35 



Summary and Conclusions 37 



Introduction 



Contact metamorphie ore deposits comprise a type of particular 

 interest because in their geologic occurrence and mineralogical makeup 

 they are intermediate between normal fissure veins and magmatic 

 segregations. During the last sixteen years much attention has been 

 given to them by students of ore genesis and ideas concerning their 

 origin have passed through many stages of development. Their general 

 occurrence at or near igneous contacts affords the common ground 

 that they are genetically related to intrusive masses, but concerning 

 the details of this relationship wide diversity of opinion exists. Does 

 the intrusion merely supply heat to the meteoric circulation, or 

 does it supply the metamorphosing solutions? Is the metamorphism 



* Published by permission of the Director of the United States Geological 

 Survey. 



