Some American Eruptive Granites

Authors

Charles Rollin KeyesFollow

Document Type

Research

Abstract

Two hypotheses, diametrically opposed, have been entertained by geologists in explaining the origin of large granitic masses. According to the one a granite is the last stage in the metamorphic alteration of mechanical sediments. According to the other a granitic mass is the product of the gradual cooling of an acidic molten magma under pressure. In the first case it is claimed that all the gradations have been traced in the same mass from undoubted elastics through slaty, schistose and gneissic phases to the truly granitic types; so that one end of an originally sedimentary deposit may be now unaltered, while the other end is a true holo-crystalline rock. On the other hand unquestionable eruptive granites are known to pass into gneiss and even into the schistose stages, through the agency of enormous compression. Regarding the facts deduced in the support of the first assumption and without referring to any specific instances, it seems quite probable that in the majority of cases bearing directly on this point sufficient discrimination has not been exercised along the lines separating the semi from the holo-crystalline areas.

Publication Date

1892

Journal Title

Proceedings of the Iowa Academy of Sciences

Volume

1

Issue

Pt. 3

First Page

24

Last Page

26

Copyright

©1892 Iowa Academy of Science, Inc.

Language

en

File Format

application/pdf

Recommended Citation

Keyes, Charles Rollin (1891) "Some American Eruptive Granites," Proceedings of the Iowa Academy of Science, 1(Pt. 3), 24-26.
Available at: https://scholarworks.uni.edu/pias/vol1/iss3/9