Abstract

The geological-structural, magmatic, seismic, and thermometric models of the Earth’s crust and upper mantle of the Sea of Japan region are considered in relation to three-dimensional rheological gravity models reflected in horizontal and vertical sections of density contrast of the tectonosphere. In the crust and the upper mantle, formal manifestations of a right-lateral strike-slip duplex were found, in association with rift-related extension zones and central vortex structures. In the central regions of the Sea of Japan, a mushroomlike low-viscosity zone of typical of plumes is mapped in the depth interval of 60–200 km. The gravity models show signs of Late Cretaceous subduction of the Pacific Plate under the continental margin and Eocene–Oligocene subduction of this plate under the Japanese island arc. The Pacific lithosphere is split into crustal and lower lithospheric plates. The depth and thickness of rigid crustal and lithospheric plates have been estimated, faults of which are observed in rift-related extension zones. Petrochemical analysis of volcanic rocks dredged from the floor of the Sea of Japan confirms the existence of two extension stages, accompanied by volcanism of an initially postsubduction (ACMB), then spreading (N-MORB) and postspreading plume (OIB) nature.

中文翻译：

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日本海构造层的结构，流变学，岩石学和地球动力学

摘要

考虑到在构造层密度对比的水平和垂直剖面中反映的三维流变重力模型，对日本海地区地壳和上地幔的地质，构造，岩浆，地震和测温模型进行了研究。在地壳和上地幔中，发现了一个右旋走滑双相的正式表现，以及与裂谷有关的伸展带和中心涡旋结构。在日本海的中部地区，典型的羽状蘑菇状低粘度带被绘制在60-200 km的深度区间内。重力模型显示了太平洋板块在大陆边缘下的晚白垩纪俯冲和日本岛弧下该板块的始新世-渐新世俯冲的迹象。太平洋岩石圈分为地壳和下部岩石圈板块。估计了硬质地壳和岩石圈板块的深度和厚度，在与裂谷有关的伸展带中观察到了它们的断层。从日本海底挖出的火山岩的石化分析证实，存在两个扩展阶段，伴随着最初的俯冲后（ACMB），然后扩散的（N-MORB）和后扩展的羽状（OIB）性质的火山活动。