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| Titel |
Genetic mechanism of hornitos in Wudalianchi Volcanic Field, Northeast China |
| VerfasserIn |
Weiyan Gao, Jianghai LI, Xiang Mao, Tianran Zhang |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250037068
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| Zusammenfassung |
| Hornitos are kind of chimney-like structures forming on the lava flow surface, which are
discovered in America, Mexico and other places in the world. Wudalianchi volcanic field in
northeast China, one of worldwide the most typical intracontinental volcanos, have perhaps
the most abundant hornitos on basic lava flows. There are at least 1537 well-preserved
hornitos discovered in Wudalianchi Volcanic field, majority of which distribute in lava flows
of a newly-built volcano erupting in 1719-1721. Especially, lava plateau with sufficient water
has hornitos concentrated distributed, in the largest scale and best developed. After
morphologic and concentrated distribution characteristic analysis, it comes to the conclusion
that water vapor in mixed gas is dominant in the formation of hornito, and gravity is also of
some importance to shape a hornito. When the basic lava with volatile overflowed near to
water area, the surface of lava condensated and consolidated while inside remained high
temperature and low viscosity. Mixed gas containing volcanic gas and vapor started to
aggregate after lava meeting groundwater, and intermittently broke surface of lava to
escape, together with some lava spattering up and stacking around the vent to form a
hornito, the inside of which stayed hollow as the routeway for gas to escape. When air
pressure failed to eject lava from top jet, growth of a hornito ended. So, hornito is
produced by the interaction of water with the hot flowing lavas, and its genetic
mechanism manifests an important example of lava landform in continental basic basalt
area.
Key Words Wudalianchi volcanic field; Hornito; Basic magma; Viscosity; Water vapor |
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