Collaborative Research: Mesozoic to Present-Day Tectonics of Northeast Russia: A Cooperative Research Program with the Yakut Science Center and NEISRI

摘要 该奖项为阿拉斯加大学费尔班克斯、密歇根州立大学、雅库特科学中心（YSC，雅库茨克，俄罗斯）和东北跨学科科学研究所（NEISRI，马加丹，俄罗斯）之间于1990年发起的合作研究计划提供支持。 该研究计划是跨学科的，利用古地磁学，地质年代学，地球化学，地震学和构造地质学研究俄罗斯东北部从西伯利亚地台边缘到鄂霍次克-楚科奇火山带（OCVB）的中生代至新生代构造历史。 研究区域包括北极和太平洋起源的中生代增生带以及北美（NA）和欧亚大陆（EU）之间的现今板块边界。 到目前为止，这个合作项目已经探测到中生代花岗岩的年龄进程，确定了西北部科雷马构造环（KSL）的广泛古地磁叠加，并获得了该地区以前公布的古地磁数据。 地震震源机制，基于区域和地球物理数据，揭示了地壳缩短的区域，驱动北冰洋的开放正在缓解挤压鄂霍次克（OK）板块向东南。 为了扩大对KSL的了解，该项目将重点关注其东南端，在那里，与在环路东北部研究的地层相似的地层从东南走向转向东北走向。 这一地区也沿着北俄克拉荷马州板块边界，在低分辨率卫星图像中可以看到断层痕迹和地震产生的特征。 下一阶段的工作将涉及NEISRI和YSC沿科雷马河和因迪吉尔卡河沿着进行的两次样带调查，并对收集的样本进行分析。 这些剖面穿过库拉-内拉板岩带、奥穆列夫卡复合岩带、伊尔因-塔斯组或其沿走向的等价物。 根据一个模型，这些单元代表了位于Kolyma-Omalon上地幔（K-OS）边缘或附近的Uyandina-Yasachnaya岛弧的晚侏罗世弧前、弧和弧后沉积物;然而，这个模型仍然存在相当大的争议，特别是与俯冲的极性有关。 这里的主要目标是确定Uyandina弧的年龄和极性，K-OS和Viliga陆棚之间的关系，古地磁叠加的程度，是否发生了造山带弯曲，晚白垩世OCVB的年龄和古纬度，详细的构造和NA-OK板块边界的位置，以及该地区的地壳结构。 这些问题的解决将有助于限制俄罗斯东北部的构造演化，这对北太平洋和北冰洋的构造有影响。 特别是，这项工作将有助于确定时间和方法的北极盆地的隔离，对古气候学的影响。 地震研究将有助于限制地壳因挤压而增厚的程度，并有助于波传播研究和核禁试监测。

Abstract This award provides supports to continue a cooperative research program between the University of Alaska Fairbanks, Michigan State University, the Yakut Science Center (YSC, Yakutsk, Russia), and the Northeast Interdisciplinary Scientific Research Institute (NEISRI, Magadan, Russia) which was initiated in 1990. The research program is interdisciplinary, using paleomagnetism, geochronology, geochemistry, seismology and structural geology to study the Mesozoic to Cenozoic tectonic history of northeastern Russia from the edge of the Siberian platform up to, and including, the Okhotsk-Chukotka volcanic belt (OCVB). The study area includes the zone of Mesozoic accretion of terranes of both Arctic and Pacific origins and the present-day plate boundary between North America (NA) and Eurasia (EU). So far, this cooperative project has detected an age progression among Mesozoic granites, identified a widespread paleomagnetic overprint in the northwestern Kolyma Structural Loop (KSL), and obtained previously published paleomagnetic data for the region. Earthquake focal mechanisms, based on regional and teleseismic data, reveal that crustal shortening in the region, driven by the opening of the Arctic Ocean is being relieved by the extrusion of the Okhotsk (OK) plate to the southeast. To expand understanding of the KSL, this project will focus on its southeastern end, where formations similar to those studied in the northeastern part of the loop turn from a southeasterly strike to a northeasterly one. This region also lies along the NA-OK plate boundary and fault traces and seismically generated features are visible in low resolution satellite images. The next phase of work will involve two transects by NEISRI and the YSC along the Kolyma and Indigirka Rivers, and analysis the samples collected. These transects cross the Kular-Nera slate belt, the Omulevka composite terrane, the Il'in-Tas formation, or their along-strike equivalents. These units represent, according to one model, the Late Jurassic forearc, arc, and back-arc deposits of the Uyandina-Yasachnaya island arc which was located on or near the edge of the Kolyma-Omolon superterrane (K-OS); this model, however, is still open to considerable debate, especially relating to the polarity of subduction. The primary objectives here are to determine the age and polarity of the Uyandina arc, the relationship between the K-OS and the Viliga shelf terrane, the extent of the paleomagnetic overprint, whether oroclinal bending occurs, the age and paleolatitude of the Late Cretaceous OCVB, the detailed tectonics and location of the NA-OK plate boundary, and the crustal structure of the region. Resolution of these problems will aid in constraining the tectonic evolution of northeast Russia, which has implications for the tectonics of the North Pacific and the Arctic Ocean. In particular, this work will aid in determining the timing and methodology of the isolation of the Arctic basin which has impact on paleoclimatology. The seismic studies will help in constraining the amount of crustal thickening resulting from compression and aid in wave propagation studies and nuclear test- ban monitoring.