Abstract Apparent variations in the morphology of the Lomonosov Ridge and its along-strike segmentation are caused by the heterogeneity of the basement. Based on the morphological diversity, we divide the Lomonosov Ridge into three segments: Siberian, Central and North American. New petrographic and geochronological data from the rock clasts sampled in the “Arctika-2007-1” expedition, are integrated with seismic and relevant mineralogical, petrographic and isotopic data. Recovered fragments of the high-grade metamorphic and siliciclastic rocks are attributed to the bedrock of the Siberian and Central Segments of the Lomonosov Ridge respectively. The mineralogical and isotopic analysis of detrital zircons from Neoproterozoic arkose defines the Grenvillian age for the basement of the Siberian Segment of the Lomonosov Ridge. The U-Pb dating of the metamorphic zircons from gneisses and schists suggests that Timanian crystalline basement of the Central Segment was affected by an upper-Ordivician (∼450 Ma) felsic magmatism, followed by the mid- to high-grade Caledonian tectonometamorphic event (∼400 Ma). The Central Segment is therefore inferred to be a frontal part of Caledonian convergent shear and fold zone. Caledonian deformation front is suggested between the northeastern and southwestern islands of De Long archipelago. Northward from the shelf break, the orogenic front is expected between the Geophysicists Spur and the main horst of the Siberian Segment. Within the Central Segment the Caledonian deformation front is inferred to stretch along the western flank of the Lomonosov Ridge.

中文翻译：

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北冰洋罗蒙诺索夫海岭的基底分割和构造结构：来自基岩年代学的见解

摘要 罗蒙诺索夫海岭形态及其沿走向分段的明显变化是由基底的异质性引起的。根据形态多样性，我们将罗蒙诺索夫海岭分为三段：西伯利亚段、中段段和北美段。来自“Arctika-2007-1”探险中采样的岩屑的新岩相学和地质年代学数据与地震和相关矿物学、岩相学和同位素数据相结合。高品位变质岩和硅质碎屑岩的恢复碎片分别归因于罗蒙诺索夫海岭西伯利亚和中央段的基岩。新元古代长石岩碎屑锆石的矿物学和同位素分析确定了罗蒙诺索夫海岭西伯利亚段基底的 Grenvillian 年龄。片麻岩和片岩变质锆石的 U-Pb 定年表明，中段的提曼阶结晶基底受到上奥底纪 (~450 Ma) 长英质岩浆作用的影响，随后是中高级加里东期构造变质事件（约 400 毫安）。因此，中央段被推断为加里东期会聚剪切褶皱带的锋面部分。德隆群岛东北部和西南部岛屿之间存在加里东变形锋。从陆架断裂处向北，地球物理学家支路和西伯利亚段的主要地块之间预计会出现造山锋。在中央段内，推测喀里多尼亚变形锋沿罗蒙诺索夫海岭的西侧伸展。