Testing the Slab Connection: A Beryllium Isotope Tracer Study in the Trans-Mexican Volcanic Belt

“会聚板块边缘”是固体地球地球化学循环的主要界面，是形成和维持宜居地球的基础。在收敛的板块边缘，由地壳和最上层地幔组成的一公里厚的岩石圈板块被拉入或俯冲到另一个岩石圈板块之下。在大约80-140公里的深度，俯冲板块释放出富含挥发物的物质，并通过高爆炸性、富含挥发物的火山活动将其“循环”回地球表面，形成排成弧形的火山链。在人类的时间尺度上，这样的单弧火山爆发曾造成致命的气候扰动（如1815年的坦博拉火山）和海啸（如1883年的喀拉喀托火山）。因此，了解弧火山作用与板块物质转移的关系仍然是地球科学研究的核心。在这类研究中，宇宙成因同位素10Be起着关键作用，因为它是一种独特的地球化学示踪剂，可以明确地识别从平板材料中回收的物质。除了这项工作的重要科学影响外，这项工作还通过促进美国和墨西哥之间的国际合作来影响社会，同时也为哥伦比亚大学的学生提供支持。这个项目的成果也将被纳入课程。最近的分析进展大大提高了弧火山岩中10Be的检测极限，现在可以从收敛边缘整合临界火山岩系列，这在以前是无法研究的。在这个项目中，10Be示踪剂将通过跨墨西哥火山带（TMVB）的研究进一步探索和测试。TMVB是一个主要的辐合边缘，它以历史上的火山喷发而闻名，这些火山喷发产生了异常广泛的火山岩光谱，它们在时间和空间上有着密切的联系。虽然之前的地球化学研究表明，这些火山岩与板块的物质回收有直接关系，但物质转移的关键细节(如何？多少钱?多快？)仍有争议。为了验证目前关于俯冲再循环的假设，将对来自TMVB中部（Popocatepetl火山及其周围）和西部（Colima火山及其周围）的一组经过充分研究的样本进行10Be分析。总的来说，该项目将为板块俯冲和弧火山作用之间的连通性及其在调节地球长期演化和维持宜居地球中的作用提供新的限制。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

'Convergent plate margins' are major interfaces of the solid Earth geochemical cycle that are fundamental to the formation and maintenance of habitable Earth. At convergent plate margins, a kilometer-thick lithospheric plate consisting of the Earth's crust and uppermost mantle is drawn - or subducted - beneath another lithospheric plate. At around 80-140 kilometers depth, the subducted plate releases volatile-rich material and 'recycles' it back to the Earth's surface via highly explosive, volatile-rich volcanism that forms chains of volcanoes aligned in arcs. On human time scales, eruptions of such single arc volcanoes have caused deadly climate perturbations (e.g. Tambora in 1815) and tsunamis (e.g. Krakatoa in 1883). Hence, understanding how arc volcanism is related to the material transfer from slab remains at the core of geoscience research. In such studies, the cosmogenic isotope 10Be, plays a pivotal role, because it is a unique, geochemical tracer that unambiguously identifies material recycled from slab material. In addition to the important scientific impact of this work, this work impacts society by fostering international collaboration between the U.S. and Mexico, and it also supports students at Columbia. Results from this project will also be incorporated into course curricula.Recent analytical advances have much improved the detection limit of 10Be in arc volcanic rocks, now allowing for integrating critical volcanic rock series from convergent margins that could not be studied previously. In this project, the 10Be tracer will be further explored and tested through a study in the Transmexican Volcanic Belt (TMVB). The TMVB is a major convergent margin which is well-known for historic eruptions that produced an unusually broad spectrum of volcanic rocks in close temporal and spatial association. While previous geochemical studies showed that these volcanic rocks have direct bearing on the material recycling from slab, crucial details of material transfer (how? how much? how fast?) remain contested. A selected set of well-studied samples from the central (Popocatepetl volcano and surrounding) and western (Colima volcano and surrounding) TMVB will be analysed for 10Be in order to test current hypotheses of subduction recycling. Overall, the project will provide new constraints on the connectivity between slab subduction and arc volcanism and its role in regulating the longterm evolution and maintenance of habitable Earth.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.