Collaborative Research: Suturing the Heart of Asia: Tectonics of the Mongol-Okhotsk Ocean Closure

在整个地质历史中，海洋盆地的闭合和超大陆的形成直接影响了自然灾害和自然资源的分布。海洋盆地和陆地分布的变化也影响了地球气候的历史和生命的进化。现代的亚洲大陆是由古老大陆的遗迹、残留的海洋盆地和岛屿链的碎片组成的，它们是在数亿年的时间里聚集在一起的。古代蒙古-鄂霍次克洋是最大的海洋之一，以前分离的片段，目前的核心亚洲大陆，但显着很少有人知道它。本研究探讨的时间和机制，通过多学科的方法，包括实地测绘和主要岩石类型的定年。该项目支持来自美国和蒙古大学的不同科学家之间的合作，以及对美国和蒙古学生的培训和指导。与此项目相关的外展工作包括为美国和国际学生提供新的教育资源，沿着为中学生提供关于板块构造、超大陆和地质年代的新教育模块。蒙古-鄂霍次克缝合带的地质年代学数据集，关于洋盆闭合和大陆碰撞模式的成员假说，如与剪刀状的地壳运动相比的主要的造山带弯曲。该项目还调查了海洋闭合期间走滑断层的作用及其与随后的造山塌陷的关系。研究成果是多学科的，包括：1）地层分析，以记录海洋-非海洋相转换和更好地描绘残余海洋盆地的亚型; 2）结构数据集，记录在Hangay Dome附近的名义西枢纽区的变形; 3）现有的低容量古地磁数据集和新的参考极的验证，以改善APWP比较;（4）建立了主要岩石类型的总体地质年代学框架。该项目包括与专注于区域岩浆作用和成矿作用的国际团队合作。该奖项反映了NSF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。

The closure of ocean basins and formation of supercontinents throughout geologic history have directly influenced the distribution of natural hazards and natural resources. Changes in the distribution of ocean basins and land masses have also impacted the history of Earth's climate and the evolution of life. The modern-day continent of Asia consists of remnants of old continents, relict ocean basins, and fragments of island chains assembled over hundreds of millions of years. The ancient Mongol-Okhotsk Ocean was one of the largest oceans that previously separated fragments of the present core of the Asian continent, and yet remarkably little is known about it. This study examines the timing and mechanisms of the closure of the Mongol-Okhotsk Ocean through a multidisciplinary approach that includes field mapping and dating of key rock types. The project supports collaborations between diverse scientists from universities in the US and Mongolia, and training and mentoring of US and Mongolian students. Outreach efforts associated with this project include new educational resources for US and international students, along with new educational modules on plate tectonics, supercontinents, and geologic time for secondary school students.This project integrates stratigraphic, paleomagnetic, structural, and geochronologic datasets for the Mongol-Okhotsk suture that are assessed in the context of competing end-member hypotheses regarding modes of ocean basin closure and continental collision, such as major oroclinal bending as compared with scissor-like suturing. The project also investigates the role of strike-slip faulting during ocean closure and its relationship to subsequent orogenic collapse. Research outcomes are multidisciplinary and include: 1) stratigraphic analyses to document marine-nonmarine facies transitions and better delineate subtypes of remnant ocean basins; 2) structural datasets that document deformation in the nominal western hinge zone near the Hangay Dome; 3) verification of existing low-volume paleomagnetic data sets and new reference poles to improve APWP comparisons; and 4) development of an overarching geochronologic framework for key rock types. The project includes collaboration with international teams focused on regional magmatism and metallogeny.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.