moinsdewatt wrote:
Who in infos on this supervolcan in New Zealand 26 000 years ago?
Good, after research:
Taupo Volcanic Zone
The volcanic area of Taupo is a fairly active volcanic area of the North Island of New Zealand. Its name comes from Lake Taupo, the caldera flooded with the largest volcano in the area.
Mount Taupo, which can be called a supervolcan, erupted 26 500 years ago, in the most recent eruption on Earth that reached the highest level on the volcanic explosive index: 8. This eruption, which caused the ejection of more than 1 000 km3 material, is at the origin of the huge caldera that now houses the lake.
The last great eruption of Lake Taupo, of a much smaller amplitude, took place between the end of the second century and the beginning of the third century. It would have emptied the lake, after which a fiery cloud would have spread volcanic ash on about 20 000 km2. More than 120 km3 material was ejected, including 30 km3 in the first minutes. After being placed in the 130 years, the date of this explosion has long been related to ancient evidence of particular weather phenomena over Rome and China (the latter documented in the Book of Later Han) to 1851. These phenomena were explained by the fact that the ashes were abundant enough to affect the color of the sky. The 170 and 180 years are also often mentioned due to a portion of the fourteen carbon dates and the 181 year corresponds to an acidic peak in the ice cores. However, the dendrochronological studies conducted in New Zealand suggest a different dating and place the eruption in the 2302, 3,4 years.
The volcanic area of Taupo extends over 350 km long and measures 50 km wide. It is located above an area of subduction of the Earth's crust.
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A recent study indicates that the Earth's crust below the volcanic area of Taupo could be only 16 km thick. A layer of magma 50 km wide and 160 km long lies 10 km deep6,7. Historical geological data indicate that some of the volcanoes in the area erupt very rarely, but violently. There is also a possibility that a rift is being formed in the volcanic area of Taupo.
https://fr.wikipedia.org/wiki/Zone_volcanique_de_TaupoGeological details:
http://www.earth-of-fire.com/article-su ... 17434.html
Volcanologists Wilson and Bellance examine a cut: at the basal level, pyroclastic deposit of the Oruanui eruption (22.600 years - 1 ° caldeira) - the clear pumice deposits, at the top right, date from the eruption Taupo 1800 Years (2 ° caldeira) - intercalated deposits date from intermediate eruptions. - photo B.Houghton / Wairakei research center.
