The challenge of quantification of ‘Greater India’ by paleomagnetism

古地磁学对“大印度”量化的挑战

• 批准号: 399131281
• 负责人: Professor Dr. Erwin Appel
• 金额: --
• 依托单位: Arbeitsgruppe Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/399131281?language=en
• 关键词: challenge; quantification; Greater; India; paleomagnetism

The continental collision of the Indian and Eurasian Plates in the Paleogene led to the formation of the Tibetan Plateau and strongly influenced the climate system. Knowing the age and mode of the collision is crucial for understanding the evolution of the Himalayan-Tibetan orogeny. This proposal suggests a paleomagnetic study to improve the knowledge on the pre-collision extent of the northern Indian Plate margin (Greater India), which is needed to determine the age when the continental Indian and Eurasian Plates got in contact. Paleogene sequences in the Tethyan Himalaya (TH) at the northern Indian plate margin only occur at three locations. Paleomagnetic data constraining the size of Greater India exist from the western TH (at Gamba); however, their significance was recently put into question. The second location (at Tingri), also in the western TH, did not yield suitable results despite several attempts. The remaining open opportunity is the Zanskar Range in the western TH, from where no data constraining the pre-collisional Greater India extent are yet available. The Late Paleocene Dibling Limestones in Zanskar will be the target of this proposal, conducting a detailed paleomagnetic study and in-depth rock magnetic analyses in order to characterize the origin of remanent magnetization. This will also include a comparison with the equivalent sequence at Gamba. If successful, we will gain a substantially improved data set constraining the Greater India extent, and obtain the first such data from the western side of the Indian Plate margin.

古近纪印度板块与欧亚板块的大陆碰撞导致了青藏高原的形成，并对气候系统产生了强烈的影响。了解碰撞的年龄和模式对于理解喜马拉雅-青藏造山带的演化至关重要。这一提议建议进行古地磁研究，以提高对印度板块边缘（大印度）北方碰撞前范围的认识，这是确定印度大陆和欧亚板块接触的年龄所必需的。位于印度板块北方边缘的特提斯喜马拉雅（TH）地区的古近纪层序仅出现在三个地点。古地磁数据限制大印度的大小存在于TH西部（在Gamba）;然而，它们的意义最近受到质疑。第二个地点（在Tingri），也在TH西部，尽管进行了几次尝试，但没有产生合适的结果。剩余的开放机会是TH西部的Zanskar山脉，从那里还没有限制碰撞前大印度范围的数据。Zanskar的晚古新世Dibling石灰岩将是本提案的目标，进行详细的古地磁研究和深入的岩石磁性分析，以确定Rebenefit磁化的起源。这还将包括与Gamba的等同序列的比较。如果成功，我们将获得一个大大改进的数据集，限制大印度范围，并获得第一个这样的数据从印度板块边缘的西侧。