Volcanic rocks from deep-seated sources of the crust-mantle transition (CMT) are geochemically distinguished from those of ocean island basalts (OIB). Here, we report geochemical data on tectonic pseudotachylytes from the Main Sayan Fault (MSF) and volcanic rocks from the Kamar-Stanovoy Zone of Hot Transtension (KSZHT) that represent the deep-seated CMT magmatic sources in the central part of the Baikal Rift System (BRS). The tectonic generation of the KSZHT magmas between 18.1 and 11.7 Ma is compared with present-day seismogenic deformations in the middle-upper crust of the South Baikal Basin and adjacent Tunka Valley, where strong earthquakes are distributed along the Main Sayan and Primorye sutures of the Siberian paleocontinent. From a detail seismic tomography model and geological evidence, we infer that the KSZHT crust–mantle magmatic processes were due to delamination and lamination of a thickened root part of the South Baikal Orogen existed in the Late Cretaceous and Paleogene. In addition, we identify similar deep-seated CMT sources for melts erupted in the past 17 Ma from a delaminated root part of the East Hangay Orogen and adjacent Orkhon-Selenga Saddle in the southwestern BRS. We suggest that both in the central and in the southwestern BRS, the deep-seated CMT magma sources designate cooperative pull-to-axis and convergent effects created in the Japan-Baikal Geodynamic Corridor and in the Indo-Asian interactional region, respectively.

中文翻译：

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伪速溶岩和火山岩的构造生成：西伯利亚南部贝加尔湖裂谷系统中地壳-幔幔过渡的深部岩浆源

地幔-幔过渡（CMT）的深层来源的火山岩在地球化学上与大洋玄武岩（OIB）有所区别。在这里，我们报告了来自主要萨彦断裂带（MSF）的构造假速溶质和热变质的卡玛尔-斯塔诺沃热带（KSZHT）的火山岩的地球化学数据，这些岩石代表了贝加尔湖裂谷系统中部的深部CMT岩浆源。 （BRS）。将18.1至11.7 Ma之间的KSZHT岩浆的构造生成与现今在贝加尔湖南部盆地和邻近的通卡河谷中上地壳中的地震成因变形相比较，那里的强地震沿着该地区的主要萨彦和滨海边疆区缝合线分布西伯利亚古大陆。从详细的地震层析成像模型和地质证据来看，我们推断，KSZHT地幔幔的岩浆过程是由于白垩纪晚期和古近纪存在的南贝加尔湖造山带增厚的根部的分层和层压所致。此外，我们还确定了类似的深部CMT来源，用于在过去的17 Ma中从东Hangay造山带的分层根部和西南BRS的相邻Orkhon-Selenga鞍座喷出的熔体。我们建议，在BRS的中部和西南部，深部的CMT岩浆源分别指定在日贝加尔地球动力学走廊和印度-亚洲相互作用区域中产生的协同拉动轴和会聚效应。我们发现了在过去的17 Ma中从东Hangay造山带的分层根部和西南BRS的相邻的Orkhon-Selenga鞍座喷出的熔体的相似的深层CMT来源。我们建议，在BRS的中部和西南部，深部的CMT岩浆源分别指定在日贝加尔地球动力学走廊和印度-亚洲相互作用区域中产生的协同拉动轴和会聚效应。我们发现了在过去的17 Ma中从东Hangay造山带的分层根部和西南BRS的相邻的Orkhon-Selenga鞍座喷出的熔体的相似的深层CMT来源。我们建议，在BRS的中部和西南部，深部的CMT岩浆源分别指定在日贝加尔地球动力学走廊和印度-亚洲相互作用区域中产生的协同拉动轴和会聚效应。