. Bulletin of the Geological Society of America. Geology. NATURE OF BATHOLITHlC INTRUSIONS 365 density of the materials successively irrupted and crystallized is rigidly followed. For a new reason, therefore, it is profitable to regard the many intru- sive bodies as forming a single composite batliolith. Favoring that con- cept, the chemical and physical nature of the unit masses, systematically variable as these are, and the general geological structure of the Okanagan Eange alike command attention. To the petrographical systematist the inclusion of such rocks as peridotites and gabbros with
. Bulletin of the Geological Society of America. Geology. NATURE OF BATHOLITHlC INTRUSIONS 365 density of the materials successively irrupted and crystallized is rigidly followed. For a new reason, therefore, it is profitable to regard the many intru- sive bodies as forming a single composite batliolith. Favoring that con- cept, the chemical and physical nature of the unit masses, systematically variable as these are, and the general geological structure of the Okanagan Eange alike command attention. To the petrographical systematist the inclusion of such rocks as peridotites and gabbros with nepheline syenites and malignites may be like classifying bats with birds, but the geological and even genetic connection of both alkaline and non-alkaline types is here manifest. Nature of batholithic Intrusions REPLACEMENT THEORY AND ILLUSTRATION Year by }rear the conviction has been growing ever stronger in the minds of many able geologists that such a batholith as any one of those here described has assumed its present size and position by actually replacing an equal or approximately equal mass of the older solid rock. The Okan-. + '+ + *++;++â¢,+ + f fHHfiH! + + + + + + + + + +. + + + + ⢠-f + + + + "+ jP5 +â¢++ + +â +. + â ++â + + * + f +,+ +'*â -h + + + ++ + + + + + + + -f + + + + + + + + + -H + + + + + + + + + + + Figure 8.âContact Surface between the Castle Peak Cranodiorite and tilted Cretaceous Sandstones and Argillites. The section is shown in the wall of a glacial cirque at the eastern end of the stocky the point marked "A" in figure 7. Scale, 1 inch to 175 feet. agan Composite batholith repeatedly illustrates this truth. The writer is frankly unable to conceive that the huge Cathedral batholith, for ex- ample, could have been formed by any process of simple injection without leaving abundant traces of prodigious rending and general disorder in the. Please note that these images are extracted from scanned page images that may have been di
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1890
