Geological understanding of the NE Atlantic and Arctic regions has increased greatly over the last two decades, revealing remarkable similarities. Continental extension in both regions onset during pausing or cessation of adjacent orogenies – the Verkhoyansk-Chukotka and Alpine orogenies – which relaxed compressional stresses and permitted extension. Severe extension accompanied by high-volume magmatism did not onset abruptly but was the culmination of long-term, regional tectonic and magmatic unrest. It was complex and piecemeal, with extension and volcanism occurring along multiple axes simultaneously, a process still ongoing in Iceland today. Large Igneous Province emplacement did not drive breakup but occurred as a consequence of continental extension. The High Arctic Large Igneous Province did not progress to breakup. As a result, much of the Arctic Ocean is floored by hyper-extended continental crust overlain by seaward-dipping reflectors. This crust resembles the passive margins of the NE Atlantic. The Alpha-Mendeleev Rise in the Arctic Ocean is a double-sided passive margin underlain by hyper-extended continental crust draped with seaward-dipping reflectors. A similar structure has been proposed for the Greenland-Iceland-Faroe Ridge. If correct, present-day volcanism in Iceland is building SDRs today. Up to ∼50% of the NE Atlantic Ocean oceanward of the continental shelves is likely underlain by at least some continental crust. For the Arctic Ocean this figure is ∼80%. Similar structures are found elsewhere, including the Madagascar Channel, the NW Indian Ocean, and the South Atlantic. These new ideas suggest promising directions of future study including assessing the true extent of continental crust in the oceans globally.

中文翻译：

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东北大西洋和北极地区之间的显着相似之处


过去二十年来，人们对东北大西洋和北极地区的地质认识有了很大的提高，揭示了显着的相似之处。这两个地区的大陆扩张都是在邻近造山运动（维尔霍扬斯克-楚科奇和阿尔卑斯造山运动）暂停或停止期间开始的，这些造山运动放松了压缩应力并允许扩张。伴随着大量岩浆活动的剧烈伸展并不是突然发生的，而是长期的区域构造和岩浆动荡的顶峰。它是复杂而零碎的，延伸和火山活动同时沿多个轴线发生，这一过程今天仍在冰岛持续进行。大型火成岩省的侵位并未导致分裂，而是大陆扩张的结果。高北极大型火成岩省并没有发展到解体。因此，北冰洋的大部分地区都被超伸展的大陆地壳覆盖，上面覆盖着向海倾斜的反射体。该地壳类似于东北大西洋的被动边缘。北冰洋的阿尔法-门捷列夫隆起是一个双面被动边缘，其下方是超伸展的大陆地壳，上面覆盖着向海倾斜的反射体。格陵兰-冰岛-法罗海岭也提出了类似的结构。如果正确的话，今天冰岛的火山活动正在创造特别提款权。大西洋东北部大陆架海洋部分的 50% 可能至少位于一些大陆地壳之下。对于北冰洋，这个数字约为 80%。其他地方也发现了类似的结构，包括马达加斯加海峡、西北印度洋和南大西洋。这些新想法提出了未来研究的有希望的方向，包括评估全球海洋中大陆地壳的真实范围。