Abstract The hierarchy of stress patterns at different evolution stages of the Central Baikal region has been studied by structural-genetic analysis of faults of different size ranks combined with other tectonophysical methods. Structural measurements were performed in the zones of the Primorsky, Olkhon, Prikhrebtovy, Buguldeika, and Kurtun faults that meet at the Buguldeika junction in the northwestern shore of Lake Baikal. Tectonic stress fields were reconstructed at the local, subregional, and regional levels in three largest fault zones (Primorsky, Olkhon, and Prikhrebtovy) and at the local and subregional levels in the smaller faults of Buguldeika and Kurtun. The stress settings in the area of the Buguldeika fault junction changed in the course of its tectonic history from Paleozoic-Mesozoic compression to Early Cenozoic strike-slip and finally to Late Cenozoic extension. The principal horizontal stress σ1 during the compression stage was oriented mainly in the NW and N—S directions. The Mesozoic N—S compression maintained northward propagation of imbricate thrusts from the Angara River headwaters as far as the Buguldeika area. The stage of strike-slip stress with N—S σ1 and W—E σ3 principal directions was reconstructed from structural measurements combined with slickenside data in the Primorsky fault zone and from slickenside data only in the Olkhon and Prikhrebtovy faults. The results show prolonged left-lateral strike-slip motions with large amounts of displacement in the Primorsky fault which delineates the Siberian craton margin. The Late Cenozoic extension stress setting has been modeled in terms of fan-like opening of large faults and clockwise rotation of upper crust blocks in the Central Baikal region.

中文翻译：

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贝加尔湖地区应力场的层次特征：以Buguldeika断层交汇点为例

摘要 通过对不同大小等级断层的构造-成因分析，结合其他构造物理方法，研究了中贝加尔湖地区不同演化阶段应力格局的层次。在贝加尔湖西北岸布古德伊卡交汇处汇合的滨海边疆区断层、奥尔洪断层、普里赫雷布托维断层、布古德伊卡断层和库尔通断层区进行了结构测量。重建了三个最大断层带（Primorsky、Olkhon 和 Prikhrebtovy）的局部、次区域和区域水平以及布古尔代卡和库尔通的较小断层的局部和次区域水平的构造应力场。Buguldeika断裂交汇处区域的应力设置在其构造历史过程中发生了变化，从古生代-中生代挤压到早新生代走滑，最后到晚新生代伸展。压缩阶段的主水平应力σ1 主要沿NW 和NS 方向取向。中生代 N-S 压缩维持了从安加拉河源头到布古德伊卡地区的叠瓦状逆冲向北传播。由构造测量结合滨海断裂带的滑坡数据和仅在奥尔洪和普里赫雷布托维断层的滑坡数据重建了具有 N—S σ1 和 W—E σ3 主方向的走滑应力阶段。结果表明，在划定西伯利亚克拉通边缘的滨海断裂带中发生了长时间的左侧走滑运动，并伴有大量位移。晚新生代伸展应力环境是根据中贝加尔湖地区大断层扇状张开和上地壳块体顺时针旋转来模拟的。