Thickness of 4-8 cm. Consists of pumice gravel and lapilli with a maximum size of 3 cm. Small amounts of a gray clay- and silt-size material and fine-grained sand, and a large amount of rock fragments 0.5-0.8 cm in size. The coarser material is concentrated in the middle of the ash layer. Distinctive features include a considerably large amount of rock debris (13%), absence of pyroxene, and a very small content of green and brown hornblendes (1-2%).
Volcanic ashes of Adak Island, Aleutian Islands, Alaska [Vulkanicheskiye peply na o-ve Adak (Aleutskiye o-va, SShA)]
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