Late Quaternary evolution of a hyperactive rhyolite magmatic system: Taupo volcanic centre, New Zealand
Late Quaternary evolution of a hyperactive rhyolite magmatic system: Taupo volcanic centre, New Zealand
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异常活跃的流纹岩岩浆系统的晚第四纪演化：新西兰陶波火山中心
DOI：
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发表时间：
2000
影响因子：
2.7
通讯作者：
B. Charlier
中科院分区：
文献类型：
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作者：
Andrew N. Sutton;S. Blake;C. Wilson;B. Charlier
陶波火山中心已经活跃了大约30万年。自约26.5 ka火山口形成Oruanui喷发以来，陶波发生了28次喷发，最小体积在0.1和>45 km 3之间变化，休止期从约20到6000年不等。所有26.5 ka后喷发的岩浆在成分和矿物学上都与前Oruanui和Oruanui火山喷发不同，并被推断为在26.5 ka或之后形成。根据全岩和矿物成分，确定了四种后Oruanui岩浆类型：一种英安质，在20.5 ka和17 ka之间形成三次喷发，三种不同的流纹岩成分在11.8至9.95，7.05至2.75和2.15至1.74 ka的离散时期喷发。流纹岩组之间的逐步成分变化和有限的内部变化表明，在短短10 000年内，三个岩石成因独立批次的岩浆侵位。1.77ka时喷发的15-35 km ~ 3的岩浆明显出现在<103年的时间内，这一短暂的滞留时间可能是造成岩浆房内缺乏分带性的原因。陶波是不寻常的大型流纹岩火山之间的高频率的活动，因为26.5万年，流纹岩成分的快速逐步变化，并在个别亚组之间的差异不明显。这些特征归因于伸展弧背景、镁铁质岩浆热能和斜长石饱和流纹岩液相线的浅斜率的综合作用。
Taupo volcanic centre has been active for c. 300 000 years. Since the c. 26.5 ka caldera‐forming Oruanui eruption 28 eruptions have occurred from Taupo, varying between 0.1 and >45 km3 in minimum bulk volume, and with repose periods ranging from c. 20 to 6000 years. All magma erupted post‐26.5 ka is compositionally and mineralogically distinct from pre‐Oruanui and Oruanui eruptives, and is inferred to have formed at or after 26.5 ka. Four post‐Oruanui magma types are identified on the basis of whole rock and mineral compositions: one dacitic, forming three eruptions between 20.5 ka and 17 ka, and three subtly distinct rhyolite compositions erupted in discrete periods from 11.8 to 9.95, 7.05 to 2.75 and 2.15 to 1.74 ka. Stepwise compositional variations between, and limited variation within, rhyolite groups suggest emplacement of three petrogenetically separate batches of magma within only 10 000 years. The 15–35 km3 of magma erupted at 1.77 ka evidently appeared in <103 years; this short residence time may have contributed to the lack of zonation within this magma chamber. Taupo is unusual amongst large rhyolite volcanoes in terms of the high frequency of activity since 26.5 ka, rapid stepwise changes in rhyolite compositions, and insignificant differentiation within individual subgroups. These traits are attributed to the combined effects of the extensional arc setting, thermal energy from mafic magma, and the shallow slope of the plagioclase‐saturated rhyolite liquidus.