Detrital zircon ages from the Loch Maree Group, Lewisian Complex, NW Scotland: confirmation of a Palaeoproterozoic Laurentia—Fennoscandia connection
Detrital zircon ages from the Loch Maree Group, Lewisian Complex, NW Scotland: confirmation of a Palaeoproterozoic Laurentia—Fennoscandia connection
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苏格兰西北部刘易斯杂岩马里湖群的碎屑锆石年龄：确认古元古代劳伦西亚-芬诺斯坎迪亚联系
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
R. Park
中科院分区：
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作者：
M. Whitehouse;D. Bridgwater;R. Park
来自苏格兰西北部刘易斯杂岩马利湖群变质沉积的碎屑锆石的离子探针锆石U-Pb年龄与劳伦蒂亚和芬诺斯坎迪亚同时代古元古代带的碎屑锆石U-Pb年龄显示出惊人的相似性，并证实了以前提出的它们之间存在联系的说法。晚太古宙的锆石(3.06-2.48 Gyr年龄)代表来自刘易斯的石英片麻岩和/或同时代的地体。古元古代锆石(2.2-2.0陀螺体)对沉积具有最大年龄限制。目前，无论是在刘易斯地区还是在更广泛的劳伦西亚-芬诺斯坎迪亚地区，这些锆石的合适的石英岩来源都是未知的，尽管它的要求与马利湖群以及年轻的岩浆弧岩在活动边缘的发展是一致的，该活动边缘可能被侧向构造移走了。与整个劳伦蒂亚-芬诺斯坎迪亚地区同时代的表壳层序进行了比较，它们在物源区年龄特征、岩性和推断的沉积环境方面表现出显著的相似性。
Ion‐microprobe U‐Pb zircon ages of detrital zircons from a metasediment of the Loch Maree Group, Lewisian Complex, NW Scotland show striking similarities to those in coeval Palaeoproterozoic belts of Laurentia and Fennoscandia, and confirm previous suggestions of a connection between them. Late‐Archaean zircons (3.06–2.48 Gyr old) represent derivation from Lewisian quartzofeldspathic gneisses, andlor a contemporaneous terrane. Palaeoproterozoic zircons (2.2–2.0 Gyrold) place a maximum age constraint upon deposition. An appropriate quartzofeldspathic source for these latter zircons is not presently known, either in the Lewisian or the wider Laurentia‐Fennoscandia region, although its requirement would be consistent with a development of the Loch Maree Group, together with juvenile magmatic arc rocks, at an active margin which was probably removed by lateral tectonics. Comparisons are made with contemporaneous supracrustal sequences throughout the Laurentia–Fennoscandia region, which exhibit marked similarities in source region age characteristics, lithologies, and inferred depositional environment.