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The Origin of Intraplate Volcanism in New Zealand

新西兰板内火山活动的起源

基本信息

批准号：
5425387
负责人：
Professor Dr. Kaj Hoernle
金额：
--
依托单位：
Forschungseinheit Magmatische und Hydrothermale Systeme
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2004
资助国家：
德国
起止时间：
2003-12-31 至 2007-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/5425387?language=en
关键词：
Origin Intraplate Volcanism New Zealand

项目摘要

Intraplate volcanism has occurred nearly continuously in different parts of Zealandia (New Zealand microcontinent) since it began to break away from Gondwana at ca 110 Ma. Even though Zealandia has moved 6000 km to the northwest with respect to the underlying mantle since it separated from Antarctica, the volcanism does not continue onto the adjacent ocean floor and thus seems to be linked to the microcontinent. The volcanism is widespread but generally of low volume except the large mid to late Miocene composite shield volcanoes forming the Banks and Otago Peninsulas. In addition, it occurred repeatedly in several restricted areas throughout the Late Cretaceous and the Cenozoic. The origin of this volcanism on Zealandia cannot be adequately explained by either of the major models for intraplate continental volcanism: 1) passage of the lithosphere over mantle hotspots (or plumes) or 2) decompression melting related to lithospheric thinning resulting from continental rifting. Combining regional age dating with petrologic and geochemical investigations, we propose to reconstruct the temporal and spatial evolution of the Late Cretaceous to Quaternary volcanism. In collaboration with New Zealand colleagues, we will develop a model explaining intraplate volcanism on Zealandia, which can also be applied to other fast moving plates with large variations in lithospheric thickness. The project promises to provide fundamental new insights into the origin of intraplate volcanism.

自110 Ma左右西兰迪亚（新西兰微大陆）从冈瓦纳分离以来，板块内火山活动几乎连续发生在其不同地区。尽管西兰洲从南极洲分离出来后，相对于地幔已经向西北移动了6000公里，但火山活动并没有延续到邻近的海底，因此似乎与微大陆有关。火山活动分布广泛，但总体上规模较小，除了形成班克斯和奥塔哥半岛的大型中至晚中新世复合盾状火山。此外，在整个晚白垩世和新生代，它在几个有限的地区反复发生。板块内大陆火山作用的两种主要模式都不能充分解释西兰洲火山作用的起源：1)岩石圈在地幔热点（或羽流）上的通道，或2)与大陆裂谷作用导致的岩石圈变薄有关的减压融化。结合区域年龄测年、岩石学和地球化学调查，重建了晚白垩世至第四纪火山活动的时空演化。在与新西兰同事的合作下，我们将开发一个模型来解释西兰洲的板块内火山活动，这个模型也可以应用于其他岩石圈厚度变化很大的快速移动板块。该项目有望为板块内火山活动的起源提供基础性的新见解。