U-Pb Geochronology of the Karoo Large Igneous Province, South Africa

9725131 Encarnaci n Flood玄武岩代表了大量（数百万立方公里）的岩浆，这些岩浆位于大陆地壳上。 AU1卡鲁和费拉尔（分别位于非洲和南极洲）的组合玄武岩区是冈瓦纳超大陆分裂的一系列玄武岩区中最古老和最大的。虽然Ferrar和卡鲁省南部似乎是同时侵位的，而且间隔时间很短（大约100万年），但卡鲁省北方的侵位时间和持续时间却没有受到很好的限制。卡鲁岩浆区的北方部分是在短时期内侵位的吗？它们与南部省是同步的吗？早期碱性岩浆活动与北部主要拉斑玄武岩岩浆活动和晚期流纹岩事件的时间关系如何？是否有任何较年轻的岩浆事件可能与非洲和南极洲的最终破裂和海底扩张有关？这些问题的答案关系到这个大火成岩省的岩浆演化，它与地幔热异常（地幔柱？）岩石圈伸展和大陆裂解，并可能提供洞察之间的关系，洪水玄武岩事件和质量迁移。该项目旨在通过获得卡鲁省各种样本的精确年龄限制来解决这些问题。 AU1

9725131 Encarnaci n Flood basalts represent voluminous (millions of cubic km) amounts of magma that were emplaced on continental crust. AU1 The combined Karoo and Ferrar (in Africa and Antarctica, respectively) flood basalt province is the oldest and largest of a series of flood basalt provinces that punctuated the breakup of the Gondwana supercontinent. Although the Ferrar and the southern part of the Karoo province appear to have been emplaced synchronously, and over a short interval (in about 1 million years) the timing and duration of the northern Karoo province is poorly constrained. Were the northern parts of the Karoo magmatic province emplaced over a brief period, and were they synchronous with the southern province? What is the timing of early alkaline magmatism in relation to the dominant tholeiitic magmatism, and the later rhyolitic events in the north? Are there any younger magmatic events that may be associated with final rupture of Africa and Antarctica and seafloor spreading? Answers to these questions bear on the magmatic evolution of this large igneous province, its relationship to mantle thermal anomalies (plumes?), lithospheric extension, and continental breakup, and may provide insight to the relationship between flood basalt events and mass extinctions. This project aims to approach these issues by obtaining precise age constraints on a variety of samples in the Karoo province. AU1