Deposits from an explosive eruption

  • Exhibition Text

    • This welded ashflow tuff is from one of the few explosively erupted pyroclastic flows at Medicine Lake volcano. The eruption occurred about 130,000 years ago, at a time when the volcano was surrounded by glaciers, and initiated extensive melting and flooding. The chocolate brown tuff is composed of andesitic ash, and the dark lumps peppered throughout are glassy fragments of dacite.

      AMNH collection

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  • For Educators

    • Topic: Earth Science

      Subtopic: Volcanoes

      Keywords: Medicine Lake (Cal.), Volcanic ash, tuff, etc., Volcanism, Volcanic eruptions

      Audience: General