Mount Tongariro: Difference between revisions

▲|text=Map centered on Mount Tongariro to show approximate selected surface volcanic deposits around it with [[andesite|andesitic]] deposits in shades of red. To the south this is continuous with volcanic deposits from [[Mount Ruapehu]]. [[Rhyolite|Rhyolitic]] [[ignimbrite]] surface deposits are various shades of violet from eruptions of the [[Taupō Volcano]]. Mixed and sedimentary deposits are not shown. The andesitic deposits of the [[Kakaramea-Tihia Massif]], and [[Pihanga]] are to the north beyond [[Lake Rotoaira]]. Clicking on the map enlarges it, and enables panning and mouseover of volcanic deposits name/wikilink and ages before present for wider volcanic context. The key to the shading of other volcanics that are shown (active in last million years odd) with panning is [[dacite]] – purple, [[rhyolite]] – violet, [[basalt]] – brown, [[Monogenetic volcanic field|monogenetic]] basalts – dark brown, undifferentiated basalts of the Tangihua Complex in Northland Allochthon – light brown, arc basalts – deep orange brown, arc ring basalts – orange brown, basaltic andesite – light red, and plutonic – gray. White shading has been used for postulated calderas (usually subsurface now).

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▲The oldest recorded volcanism in the area was at 933,000 ± 46,000 years ago at [[Hauhungatahi]], northwest of Ruapehu. There is then a gap in identified materials until a small lava inlier on the western side of Tongariro that has been dated at 512,000 ± 59,000 years ago and is essentially buried by more recent activity.<ref name="RuapehuTongariro2021Review">{{Cite journal |last1=Leonard |first1=Graham S. |last2=Cole |first2=Rosie P. |last3=Christenson |first3=Bruce W. |last4=Conway |first4=Chris E. |last5=Cronin |first5=Shane J. |last6=Gamble |first6=John A. |last7=Hurst |first7=Tony |last8=Kennedy |first8=Ben M. |last9=Miller |first9=Craig A.|last10=Procter|first10=Jonathan N. |last11=Pure |first11=Leo R. |last12=Townsend |first12=Dougal B. |last13=White |first13=James D. L. |last14=Wilson |first14=Colin J. N. |date=2021-05-02 |title=Ruapehu and Tongariro stratovolcanoes: a review of current understanding |journal=New Zealand Journal of Geology and Geophysics |language=en |volume=64 |pages=389–420 |doi=10.1080/00288306.2021.1909080 |issue=2–3 |s2cid=235502116 |doi-access=free}}</ref> The {{cvt|90|km3|cumi}} cone and {{cvt|60|km3|cumi}} ring-plain of the complex has multiple eruptive centres aligned with the [[Taupō Volcanic Zone|Taupō volcanic rift]] and bounded by the [[Waihi Fault Zone|Waihi]] and [[Poutu Fault Zone|Poutu fault zones]]. The formation of these began about 304,000 years ago in the Tama lakes area and definitely was established by 230,000 years ago.<ref name ="Pure2020">{{Cite journal |last1=Pure |first1=L. R. |last2=Leonard |first2=G. S. |last3=Townsend |first3=D. B. |last4=Wilson |first4=C. J. N. |last5=Calvert |first5=A. T. |last6=Calvert |first6=A. T. |last7=Cole |first7=R. P. |last8=Conway |first8=C. E. |last9=Gamble |first9=J. A. |last10=Smith |first10=T. B. |title=A high resolution 40Ar/39Ar lava chronology and edifice construction history for Tongariro Volcano, New Zealand |url=https://www.sciencedirect.com/science/article/abs/pii/S0377027320301086 |journal=Journal of Volcanology and Geothermal Research |language=en |volume=402 |pages=106993 |date=2020-10-01 |doi=10.1016/j.jvolgeores.2020.106993 |bibcode=2020JVGR..40306993P |hdl=10468/10345 |hdl-access=free |access-date=5 June 2022 |archive-date=5 June 2022 |archive-url=https://web.archive.org/web/20220605192627/https://www.sciencedirect.com/science/article/abs/pii/S0377027320301086 |url-status=live }}</ref> The eruptive centres extend from the Te Maari craters in the northeast to the Tama Lakes in the southwest and include the more classic cone of [[Mount Ngauruhoe]] which like North Crater, another symmetrical but smaller cone, required the absence of ice after the last ice age to form. Tongariro displays evidence for extensive Quaternary glaciation in the form of moraines and lava-ice interaction textures.<ref name= "Pure2020" /> However Pukeonake is off this axis, approximately 6 km west of the linear vent zone, but is considered to be a satellite vent. There was an intense period of large explosive eruptions around 11,000 years ago from multiple vents between Tongariro and Ruapehu (the Pahoka-Mangamate sequence).<ref name="RuapehuTongariro2021Review" />