Abstract

A model of the geological evolution of the Sea of Okhotsk is presented based on data from radioisotope age determinations and the mineral and isotope-geochemical composition of Late Mesozoic–Cenozoic volcanic rocks. We discuss the probable interrelationship between gas geochemical manifestations of gas fluxes with anomalous methane concentrations and the formation of gas hydrates, along with the occurrence of volcanic processes in the Sea of Okhotsk, fault zones, and different geological structures of basement and sedimentary deposits, landslides, and earthquakes. As a result of the studies, the nature of each volcanic stage has been determined. These include the Late Cretaceous continental-marginal belt stage (calc-alkaline), the Eocene transform-marginal (adakite) stage, and the Pliocene-Pleistocene island arc stage in the southern part of the Sea of Okhotsk. The sources of magma generation have been recognized, namely, the lithosphere subcontinental, asthenosphere oceanic, and plume-oceanic (OIB). The change in geodynamic regimens was traced back from the Late Cretaceous subduction regimen to the Maastrichtian–Datian transform-marginal, which continued as far as the Pliocene and ended at the resumption of the Pliocene–Pleistocene subduction of the Pacific Plate beneath the Eurasian continent. This involved the processes of destruction of the subduction plate, lithosphere and asthenosphere diapirism, and lower mantle plume upwelling. In the periods of geodynamic, seismotectonic and volcanic activities, gas migrated along the fault zones from the depth to the surface, together with different volcanic substrates ascending through the upper and lower mantle. Gas contained CO₂, CH₄, H₂, He, N₂, O₂, and superheated steam (Н₂О). Gas plays an important dynamic and physicochemical role in the evolution of the Sea of Okhotsk. At the present stage, gas fluxes migrating from the depth to the surface manifest as gas bubbles penetrating from the bottom sediments into the water column, with some portion of gas penetrating into the atmosphere. In the areas with gas fluxes, the fields containing anomalous concentrations of hydrocarbons, gas hydrate, carbon dioxide, hydrogen, and helium result in the formation of gas hydrates and associations of authigenic minerals and various geochemical elements.

中文翻译：

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白垩纪-新生代构造活动在鄂霍次克海中的气体流动

摘要

鄂霍次克海的地质演化模型基于放射性同位素年龄测定以及晚中生代-新生代火山岩的矿物和同位素-地球化学组成提供了数据。我们讨论了甲烷浓度异常的气体通量的气体地球化学表现与气体水合物的形成之间的可能相互关系，以及鄂霍次克海，断层带以及基底和沉积沉积物，滑坡的不同地质结构在火山过程中的发生。和地震。研究结果确定了每个火山阶段的性质。这些包括白垩纪晚期大陆-边缘带阶段（钙碱性），始新世转变-边缘（赤铁矿）阶段，鄂霍次克海南部的上新世至更新世岛弧阶段。岩浆产生的来源已得到公认，即岩石圈次大陆，软流圈大洋和羽流（OIB）。地球动力学方案的变化可以追溯到白垩纪晚期俯冲方案到马斯特里赫特-大田的转换边缘，一直延伸到上新世，并在欧亚大陆下太平洋板块的上新世-更新世俯冲恢复时结束。这涉及到俯冲板块的破坏，岩石圈和软流圈的透散作用，以及下地幔柱上升流。在地球动力学，地震构造和火山活动期间，气体沿着断层带从深处迁移到地表，以及通过上地幔和下地幔上升的不同火山基底。气体含CO₂，CH ₄，H ₂，他，N ₂，O- ₂，和过热蒸汽（Н ₂ О）。天然气在鄂霍次克海的演变中起着重要的动力学和物理化学作用。在现阶段，从深处迁移到地面的气体通量表现为气泡从底部沉积物渗透到水柱中，而一部分气体渗透到大气中。在有气体通量的地区，含有异常浓度的碳氢化合物，天然气水合物，二氧化碳，氢气和氦气的区域会导致天然气水合物的形成以及自生矿物和各种地球化学元素的结合。