Geomorphology and evolution of the volcanic fields in New Mexico have been studied. Thirteen volcanic fields being active in the late Tertiary-Quaternary are classified into 4 - A, B, C, and D types. A-type volcanic fields are simple lava fields, composed of basaltic lava flows, scoria cones, tuff rings, tuff cones, and small shields. B-type volcanic fields are lava fields on which small to medium-scale andesitic stratovolcanoes and dacitic to rhyolitic lava domes stand. C-type volcanic fields are composed of lava fields and large-scale andesitic to rhyolitic stratovolcanoes. D-type volcanic fields are mainly composed of large calderas and large-scale rhyolitic pyroclastic flow surfaces, accompanied with small-scale basaltic lava fields. It could not be asserted that the difference of the types of the volcanic fields depends on the difference of evolutional stages. It seems that the difference rather depends on regional characteristics-thickness of crust, field stress, thermal condition of upper mantle etc.
米国New Mexico州の火山地域の地形とその分類
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