Abstract—

This paper presents the results of geochemical studies of sandstones of the Aga–Borshchovochnyi complex in the Onon fragment of the Aga Terrane (Tutkhaltui Valley) within the Mongol–Okhotsk Fold Belt, as well as the results of U–Th–Pb (LA-ICP-MS) geochronological and Lu–Hf isotope geochemical studies of detrital zircons from these rocks. It was established that the youngest population of detrital zircons in the studied sandstones has an age of 196 ± 8 Ma. This indicates the Early Jurassic age of the sediments that were previously dated as Middle Paleozoic. The geochemical features of sandstones suggest that they were deposited in the active continental margin or island arc setting at the final stage of the closure of the Mongol–Okhotsk Paleocean.

中文翻译：

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蒙古-鄂霍次克褶皱带阿加地体奥农片断下侏罗统砂岩年龄及地球动力学背景

摘要-

本文介绍了蒙古-鄂霍次克褶皱带内阿加地体（图特哈图伊河谷）的奥农碎片中阿加-博尔什楚沃奇尼杂岩砂岩的地球化学研究结果，以及铀-钍-铅（LA- ICP-MS) 对这些岩石中碎屑锆石的年代学和 Lu-Hf 同位素地球化学研究。已确定所研究砂岩中最年轻的碎屑锆石年龄为 196 ± 8 Ma。这表明以前确定为中古生代的沉积物的早侏罗世时代。砂岩的地球化学特征表明，它们沉积在蒙古-鄂霍次克古洋闭合的最后阶段的活动大陆边缘或岛弧环境中。