The 616 Ma Old Egersund Basaltic Dike Swarm, Sw Norway, and Late Neoproterozoic Opening of the Iapetus Ocean
The 616 Ma Old Egersund Basaltic Dike Swarm, Sw Norway, and Late Neoproterozoic Opening of the Iapetus Ocean
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616 Ma老埃格尔松玄武岩墙群，挪威西南部，与新元古代晚期土卫八洋的张开
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
O. Breemen
中科院分区：
文献类型：
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作者：
B. Bingen;D. Demaiffe;O. Breemen
挪威西南部的埃格尔松堤群由 11 条走向 ESE-WNW 的玄武岩堤组成。定义了两组：具有拉斑铁矿亲和力的斑状斑晶岩脉和拉斑铁矿对碱性亲和力的非斑状岩脉。最碱性岩脉中的斜锆石的 U-Pb 侵入年龄为 616 ± 3 Ma。该群与波罗的海新元古代西南（现今方向）托恩奎斯特边缘平行。它与拉布拉多长距离群同时期，拉布拉多群与劳伦西亚原阿巴拉契亚边缘东南部平行。这两个群都与导致土卫八海洋开放的裂谷有关。波罗的海西部和劳伦西亚东部新元古代与裂谷相关的岩浆套的时间相关性表明，Iapetan 大洋盆地的历时开放时间约为 10 世纪。 610 Ma 沿着波罗的海的西北巴尔托斯坎迪亚边缘，大约在 610 Ma。 550 Ma 沿劳伦大陆原阿巴拉契亚边缘和波罗的海托恩奎斯特边缘。
The Egersund dike swarm of SW Norway is made up of 11 basaltic dikes trending ESE‐WNW. Two groups are defined: porphyritic dikes with bytownite phenocrysts of tholeiitic affinity and aphyric dikes of tholeiitic to alkaline affinity. Baddeleyite in the most alkaline dike gives a U‐Pb intrusive age of 616 ± 3 Ma. The swarm is parallel to the Neoproterozoic southwestern (present‐day orientation) Tornquist margin of Baltica. It is coeval with the Long Range swarm of Labrador which is parallel to the southeastern proto‐Appalachian margin of Laurentia. Both swarms are related to rifting that resulted in the opening of Iapetus ocean. Chronocorrelation of Neoproterozoic rift‐related magmatic suites in western Baltica and eastern Laurentia suggests diachronic opening of Iapetan oceanic basins at ca. 610 Ma along the northwestern Baltoscandian margin of Baltica and at ca. 550 Ma along the proto‐Appalachian margin of Laurentia and Tornquist margin of Baltica.