thumbnail

K/Na ratio of Cenozoic igneous rocks of the western United States

Geochimica et Cosmochimica Acta

By:

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time

Abstract

The potassium and sodium content of chemically analysed Cenozoic igneous rocks from about 150 areas of the western United States has been examined. For each area a plot of the molecular proportion K2O (K2O + Na2O) [Niggli's k-value] is shown, and the projected k-value determined at 50 and 60 weight per cent SiO2. The k-values are plotted and contoured on maps of the western United States. These maps show that potassium is least abundant relative to total alkali (when rocks of the same SiO2 content are compared) in a zone along the Pacific Coast, becomes more abundant eastward, and is highest in the Colorado Plateau and Northern Rocky Mountains. These k-value variations can be related to regional variations in the abundance of certain trace elements and of different types of older granitic rocks, and to Bouguer gravity maps. This correspondence indicates that the alkali ratio of Cenozoic igneous rocks is closely related to the character of the crust where the rocks are formed. ?? 1962.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
K/Na ratio of Cenozoic igneous rocks of the western United States
Series title:
Geochimica et Cosmochimica Acta
Volume
26
Issue:
1
Year Published:
1962
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
101
Last page:
130
Number of Pages:
30