Amygdales in Columbia River lavas near Freedom, Idaho

Eos, Transactions, American Geophysical Union



Incomplete study of seven amygdales from the Columbia River lava‐flows along Slate Creek, a tributary of Salmon River, near Freedom in north‐central Idaho, reveals that these small objects are of unusual geological and mineralogical interest. This paper includes an outline of the geology of the area from which the amygdales came, a description of the amygdales, and a brief account of the periodic tilting of a large fault‐block as revealed by them.

Slate Creek enters Salmon River near the eastern border of the Columbia Plateau. In this locality the thick Lower Middle Miocene lava‐flows of the plateau country are interbedded with the sediments of many local lakes formed periodically as successive flows dammed the streams flowing westward from the higher country to the east. A section measured near the mouth of Slate Creek shows the volcanic rocks there to be 2600 feet thick. At some places on the Plateau farther from its borders the flows aggregate more than twice that thickness.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Amygdales in Columbia River lavas near Freedom, Idaho
Series title Eos, Transactions, American Geophysical Union
DOI 10.1029/TR018i001p00239
Volume 18
Issue 1
Year Published 1937
Language English
Publisher American Geophysical Union
Description 5 p.
First page 239
Last page 243
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