俄罗斯-蒙古地学断面地壳模型的地质-地球物理资料综合研究  

Geological-geophysical models of the Earth's crust along the Russian-Mongolian geotransects

作　　者：Evgeny Kh.TURUTANOV Evgeny V.SKLYAROV Valentina V.MORDVINOVA Anatoly M.MAZUKABZOV Viktor S.KANAYKIN Evgeny Kh.TURUTANOV;Evgeny V.SKLYAROV;Valentina V.MORDVINOVA;Anatoly M.MAZUKABZOV;Viktor S.KANAYKIN(Institute of the Earth's Crust Siberian Branch of the Russian Academy of Science,Lermontov ave.128,Irkutsk 664033,Russia;Irkutsk National Research Technical University,Lermontov ave.83,Irkutsk 664074,Russia)

机构地区：[1]Institute of the Earth's Crust Siberian Branch of the Russian Academy of Science,Lermontov ave.128,Irkutsk 664033,Russia [2]Irkutsk National Research Technical University,Lermontov ave.83,Irkutsk 664074,Russia

出　　处：《地学前缘》2021年第5期260-282,共23页Earth Science Frontiers

摘　　要：地学断面是指地壳的垂直剖面,主要通过对地质和地球物理资料的综合分析来揭示构造带的性质及其空间关系。横断面的研究所采用的数据基本包括100 km宽区域地质图、上地壳的地质剖面图、重磁图(沿横断面的重磁剖面图)以及地壳的地震波速度、密度和其他地球物理属性的剖面图。这些数据被用于构建综合的数据剖面图(结果图),以展示各种地球动力学条件下(裂谷、海洋、碰撞带、造山盆地、大陆地台和岩浆弧,包括安第斯岛弧、活动大陆边缘、海沟、弧前和弧后盆地)的特定的岩石组构。本项目的研究目标是根据研究区现存的地质和地球物理数据的综合解释,统一图例,建立研究区深部剖面,以确定地体的空间关系及其在板块构造方面的地球动力学性质。前人已分别对东西伯利亚南部和蒙古境内的多个地体进行了构造划分,并对它们的地球动力学性质和时空关系进行了分析。研究结果显示该系列地体为早古生代、中晚古生代和晚古生代—早中生代的岛弧和微大陆。此外,研究还识别出了中-晚古生代和晚古生代-早中生代安第斯型活动大陆边缘、晚古生代-早中生代被动大陆边缘和早白垩世裂谷。与岛弧和安第斯型活动大陆边缘相关的岩体被推覆至相邻大陆和微陆块上,部分推覆宽度可达150 km。目前已开展泥盆纪到晚侏罗世时期蒙古鄂霍次克海地区的古地球动力学重建。“非地槽”型花岗岩类岩浆作用在板块构造方面找到了直接且合理的解释,其中泥盆纪-石炭纪和二叠纪-三叠纪岩浆作用区域对应于安第斯型活动大陆边缘,中—晚侏罗世岩浆作用则与西伯利亚/蒙古中国大陆板块碰撞有关。碰撞岩浆作用中亚碱性(地幔)元素的存在及其所在的构造区域在很大程度可以说明蒙古鄂霍次克海闭合后,巨厚大陆岩石圈下曾经发生过持续的大洋裂谷活动(�Transects are vertical sections of the Earths crust,which reveal the nature of tectonic zones,as well as their spatial relationships through a combined analysis of their geology and geophysics.Transect documents contain a geological map for a strip of land 100 km wide,a geological section of the upper crust,gravity and magnetic maps(and/or corresponding profiles along the transect),and a geophysical profile of the crust,differentiated by seismic velocities,densities and other geophysical properties.These data are used to compose a combined cross-section(the resulting section),which shows a set of rocks typical of various geodynamic conditions(rifts,oceans,collision zones,orogenic basins,continental platforms and magmatic arcs,including Andean island arcs,active continental outskirts,trenches,basins of front and rear arcs).The objective of this project was to build deep sections according to unified legends based on the interpretation of all available geological and geophysical data in order to determine the spatial relationship of terranes and their geodynamic nature in terms of plate tectonics.A number of terranes have been discriminated in the territory of the southern part of Eastern Siberia and the territory of Mongolia,and their geodynamic nature and space-time relations were analysed.The terranes were found out to be Vendian Early Paleozoic,Middle-Late Paleozoic and Late Paleozoic Early Mesozoic island arcs and microcontinents.Moreover,Middle-Late Paleozoic and Late Paleozoic Early Mesozoic Andean-type active continental margins and Late Paleozoic Early Mesozoic passive margins and Early Cretaceous rifts were identified and studied.The rock complexes related to the island arcs and Andean-type active continental margins are thrust over the bordering continents and microcontinents,the width of the respective tectonic nappes attaining 150 km.Schematic paleogeodynamic reconstructions for the area of the Mongolia-Okhotsk ocean have been performed,spanning the period from Devonian to Late Jurassic.“Non-geosyncl

关 键 词：地质 地球物理 地壳横断面 

分 类 号：P542[天文地球—构造地质学]