The Origin of Intraplate Volcanism in New Zealand

西兰迪亚(新西兰微大陆)自约110 Ma脱离冈瓦那以来，板内火山活动几乎不间断地在不同地区发生。尽管自从南极洲分离以来，西兰迪亚相对于下伏地幔已向西北方向移动了6000公里，但火山活动并未持续到邻近的洋底，因此似乎与微大陆有关。除了中新世晚期形成班克斯和奥塔哥半岛的大型复合地盾火山外，火山活动普遍存在，但总体规模较小。此外，在整个晚白垩世和新生代，它在几个限制区域反复发生。西兰迪亚火山活动的起源不能用板内大陆火山作用的两种主要模式来充分解释：1)岩石圈越过地幔热点(或热柱)，或2)与大陆裂谷导致的岩石圈减薄有关的减压熔融。结合区域测年、岩石学和地球化学研究，重建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，我们将开发一个解释西兰迪亚板块内火山作用的模型，该模型也可以适用于岩石圈厚度变化较大的其他快速移动的板块。该项目有望为板内火山活动的起源提供新的根本见解。

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.