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Phrase ash flow tuff

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  • A few ash flow tuffs also constitute this phase of volcanism.
  • The major ash flow tuff sheets produced, range in volume from 35 to 650 km 3.
  • The rhyolites and ash flow tuffs of the Spavinaw are essentially identical to the volcanics of the St . Francois mountains ( the Washington County volcanics ).
  • Glennies Creek Dam spillway is an unlined cutting in welded ash flow tuff which supplied the entire rock fill requirement for the construction of the dam embankment.
  • Ash flow tuffs and block-and-ash-flow deposits from this explosive eruption traveled down the Ash Creek and Bluff Creek valleys that reach depths of.
  • Metamorphosed ash flow tuffs are widespread in the Precambrian rocks of northern New Mexico, which indicates that caldera complexes have been important for much of Earth's history.
  • The Sturgeon Lake Caldera contains volcanic units that outcrop over from east to west with up to five separate, major ash flow tuff units with thickness ranging from to.
  • Guatemala City is not underlain by any carbonate rock; instead, thick deposits of volcanic ash, unwelded ash flow tuffs, and other pyroclastic debris underlie all of Guatemala City.
  • However, these natural stone balls are megaspherulites that have been released by erosion from a 20-to 30-million-year-old ash flow tuff, which originally enclosed them and in which they formed.
  • Also found are outcrops of strongly jointed volcanic glass in Clear Creek Canyon along the I-70 corridor called the Skinner Canyon Ignimbrites a spectacular development and exposures of columnar joints in the rewelded ash flow tuffs here are almost unique in the Colorado Plateau because of the limited exposures of these types of volcanic rocks.
  • The Long Valley Caldera in eastern California is also a complex volcano; the San Juan Mountains in southwestern Colorado are formed on a group of Neogene-age caldera complexes, and most of the Mesozoic and Cenozoic rocks of Nevada, Idaho, and eastern California are also caldera complexes and their erupted ash flow tuffs.