CAREER: Petrogenetic Affinity of Miocene Granites to Test the Mid-crustal Channel Flow Model in the Himalaya

该研究项目的主要目标是测试通道流动模型，该模型预测印度地壳的花岗岩熔体在青藏高原下的推力作用下向南移动到喜马拉雅山的地形侵蚀锋。这些花岗岩暴露在喜马拉雅地形前缘的大喜马拉雅层序中，在更北的特提斯喜马拉雅层序的花岗片麻岩圆顶中，并可能沿青藏高原南部喀喇昆仑断裂暴露。本文将结合野外观测、U-Pb和40Ar/39Ar年代学、Nd和Pb同位素地球化学对河道流动模型进行验证，以确定喜马拉雅西部（印度）和喜马拉雅东部（西藏南部）中新世花岗岩的来源。本研究结果将支持或反对喜马拉雅地区的河道流动模式；确定了喀喇昆仑、喜马拉雅和藏南地区中新世花岗岩的来源；在青藏高原下构造印度地壳北段；并可以确定喀喇昆仑断层是否是一个地壳尺度的构造，以及约束断层上滑动的时间。为喜马拉雅山脉开发的地球动力学模型通常被输出到世界范围内的其他碰撞造山带：最近，河道流动模型已被应用于阿巴拉契亚山脉、加拿大科迪勒拉山脉和Hellenides山脉。在大陆碰撞形成的地形梯度背景下，河道流动模式明确地将气候驱动的地表过程与深部地壳过程联系起来，从而将地质研究推向了将构造过程与区域和全球气候变化联系起来的新方向。该项目的教育计划在旧金山州立大学开设了一门新课程“地球科学的科学教育合作伙伴”，该课程将使地球科学专业的本科生和研究生与三至六年级的教师合作，在旧金山联合学区的教室里共同开发和教授课程。在加州，一个地震危险大的地区，一个在气候变化之前就面临着重大土地利用和水资源挑战的州，特别需要有科学素养的公民。加州科学标准要求将地球科学作为K-12科学教学重点的唯一一年是六年级；在小学阶段（到五年级），地球科学大约占必修科学教学的三分之一，而在高中阶段，这一比例甚至更小，这使得三年级到六年级的干预成为提高加州公立学校K-12年级地球科学素养的最有希望的机会。这一伙伴关系项目最重要的广泛影响将是培养一批具有课堂教学和外联经验的毕业生骨干，以及一批被授权教授引人入胜的地球科学课程的小学教师。该职业奖由地球科学部的构造学、岩石学和地球化学以及教育和人力资源项目支持。

The main goal of the research project is to test the channel flow model that predicts granite melts of Indian crust thrust beneath the Tibetan plateau are gravitationally-driven south to the topographic erosional front of the Himalaya. These granites are exposed in the Greater Himalaya Sequence in the topographic front of the Himalaya, in granite gneiss domes in the Tethyan Himalaya Sequence further north, and may be exposed along the Karakoram fault in the southern Tibetan plateau. The channel flow model will be tested using a combination of field observations, U-Pb and 40Ar/39Ar geochronology, and Nd and Pb isotope geochemistry to determine the sources of these Miocene granites in the western Himalaya (India) and the eastern Himalaya (southern Tibet). Results of this research will support or argue against the channel flow model in the Himalaya; identify the source of Miocene granites in the Karakoram, Himalaya, and southern Tibet; establish the northern reach of underthrust Indian crust beneath the Tibetan plateau; and may establish whether the Karakoram fault is a crustal-scale structure as well as constrain the timing of slip on the fault. Geodynamic models developed for the Himalaya are commonly exported to other collisional orogens worldwide: most recently, the channel flow model has been applied to the Appalachians, the Canadian Cordillera, and the Hellenides. The channel flow model explicitly links climate-driven surface processes with deep crustal processes in the context of topographic gradients set up by continental collision and as a result has pushed geological research in new directions connecting tectonic processes to regional and global climate change.The education plan for this project creates a new course at San Francisco State University, "Science Education Partners in Geosciences", that will partner undergraduate and graduate students in Geosciences with grade 3 to 6 teachers to co-develop and co-teach lessons in San Francisco Unified School District classrooms. In California, an area of great earthquake hazard, and a state with major land use and water resource challenges even prior to climate change, there is a particular need for scientifically literate citizens. The only year in which California science standards require Earth Science as the focus of K-12 science instruction is the 6th grade; Earth Science comprises approximately one-third of required science instruction at the elementary level (through grade 5), and an even smaller component in high school, making intervention at grades 3 through 6 the most promising opportunity to enhance K-12 earth science literacy in California public schools. The most important broader impact of this partnership program will be the creation of a cadre of graduates with experience in classroom teaching and outreach, and a group of elementary school teachers empowered to teach engaging earth science lessons.This CAREER award is supported by Tectonics, Petrology and Geochemistry, and Education and Human Resources programs in the Division of Earth Sciences.