精品文档---下载后可任意编辑青藏高原东北缘晚中生代玄武岩岩石学地球化学及其成因的开题报告摘要：青藏高原东北缘的晚中生代玄武岩是讨论该区域地质演化历史和岩石圈动力学过程的重要记录，尤其是在揭示在印度板块下俯冲过程中地幔流体的分布、激活和其对陆内挤压应力的作用方面有着重要的意义。本讨论选取了青海省同仁县玄武岩作为讨论样品，通过岩石学观察和地球化学分析，阐明了该岩石的岩石学特征和成因。通过对同仁县玄武岩的岩石学特征观察，发现其晶体形成较细小，陶瓷质地; 岩石呈中基性、亚铁镁质碱性，岩石中矿物组成以斜长石、辉石和黑云母为主，少量透闪石和绿帘石等。地球化学分析结果表明，同仁县玄武岩富集大离子亲石元素如 K、Ba、Sr 和 Rb，亏损 Nb、Ta 等高场强元素，具有负 Eu 异常特征，属于富集地幔源岩石。综合岩石学和地球化学特征，推测同仁县晚中生代玄武岩的成因可能与印度板块下俯冲过程中地幔物质上升有关，岩石可能来源于幔源性基性成分，通过混染作用混入了一定的地壳物质而形成。讨论结果对于深化理解青藏高原东北缘晚中生代玄武岩的成因和地质演化史提供了一定的科学依据和参考价值。关键词：青藏高原，东北缘，晚中生代，玄武岩，岩石学，地球化学，成因Abstract:The Late Mesozoic basalts in the northeastern Tibetan Plateau are important records for studying the geological evolution history and lithospheric dynamics processes of this region, especially for revealing the distribution, activation and effects of mantle fluids during the subduction of the Indian Plate and its impact on the intracontinental compression stress. We chose the basalts in Tongren County, Qinghai Province as the research sample, and clarified their geological and geochemical characteristics and genesis through petrological observations and geochemical analysis.Through the observation of petrological characteristics of Tongren County basalts, it was found that the crystal formation is relatively small and the texture is ceramic-like. The rock is moderately basic and sub-ferromagnesian alkaline. The main 精品文档---下载后可任意编...
