278 



STRUCTURAL GEOLOGY OF NORTH AMERICA 



la 



SCALE 



IN MILES 

 10 



20 



Fig. 17.15. Diagrammatic east-west section through the Okanogan composite batholith. s, schists 

 and associated Paleozoic rocks; Cr, Pasayton lower Cretaceous arkose sandstones; la, Chopaka 

 peridotite; lb, Basic complex; 2, Ashnola gabbro; 3a, Remmel batholith, western phase; 3b, 

 Remmel batholith, eastern phase; 3c, Osoyoos batholith; 4, Kruger alkaline body; 5, Similkameen 



materials a west-lying volcanic archipelago and orogenic belt may be 

 postulated similar to that of California and western Nevada, but possibly 

 the regions of sedimentation were complicated by geanticlines which 

 also were sites of volcanic activity. 



Cretaceous strata have a more restricted distribution. Lower Cretaceous 

 deposits of interior basin type occur in the Rockies and eastward. A 

 narrow trough of them is recognized west and south of Kamloops Lake in 

 mid-interior and east of the great Coast Range batholith. A small deposit 

 occurs on the west coast of Vancouver Island. It would appear that the 

 Belt geanticline had widened westward from Jurassic time, and perhaps 

 another broad geanticline existed in the site of the Coast Range batholith 

 and Vancouver Island. 



In Late Cretaceous time the entire interior from the Rocky Mountains 

 to the Strait of Georgia had become emergent and only flanking deposits 

 accumulated. This was undoubtedly a consequence of the great batho- 

 lithic intrusions and previous compressional orogeny of the broad cordil- 

 leran region. 



Nevadan Orogeny 



Batholiths of the International Border. An almost continuous succes- 

 sion of batholiths stretches more than 350 miles along the international 



batholith; 6a, Cathedral batholith, older phase; 6b, Park granite stock; 7, Cathedral batholith, 

 younger phase. 



The components of the batholith are numbered in order of intrusion. Vertical scale is exag- 

 gerated twice the horizontal. After Daly, 1912. 



border between Washington and British Columbia. These have been de- 

 scribed by Daly (1912), Smith and Calkins (1904, 1906), and Smith 

 (1904), and later studies have been made by Waters, Krauskopf, Camp- 

 bell, and Pardee (see references in Waters and Krauskopf, 1941). It is 

 highly probable that the plutons form the basement southward under vast 

 areas of lavas of the Columbia Plateau because granitic rocks appear in 

 the Ochoco-Blue Mountains uplift of central and eastern Oregon midway 

 to the Klamaths and Sierra Nevada (Waters, 1933) and also southeast- 

 ward under more lavas through the Thatuna batholith to the great Idaho 

 batholith. 



Intrusions of peridotite, gabbro, and diorite are associated with the 

 prevailing granodiorite of the great batholiths. Quartz monzonite, quartz 

 diorite, and granite are locally widespread. In certain areas where the 

 succession of intrusions has been worked out, it is a cycle similar to that of 

 the Sierra Nevada, viz., first the smaller bodies of ultrabasic rock, then 

 gabbros and diorites, and finally the great granitoid bodies. Pegmatites are 

 rare in the batholiths along the border in Washington, but aplite masses 

 locally of almost batholithic proportions crosscut the earlier intrusions. 

 The borders of the batholiths commonly show discordant relations to the 

 country rock, and extensive masses of contact breccia are found along the 

 intrusive margins (Waters, 1933). Some of the best examples of dis- 



