fine-grained glassy olivine-free clinopyroxene andesite. Sample is from the center of an isolated pillow within a thick deposit of monolithologic hyaloclastite and interbedded broken pillow breccia layers and autointrusive flow tongues. Whole rock K-Ar date of 1.99 +/- 0.08 m.y. Sample is from pre-Tanada lava, in Tanada area.
Shield volcanoes in the Wrangell Mountains, Alaska
This website is supported by the U.S. Geological Survey under Cooperative Agreement Grant G19AC00060 and G19AC00171.
Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey.