A U/Pb age for the Shetland Islands oceanic fragment, Scottish Caledonides: evidence from anatectic plagiogranites in ‘layer 3’ shear zones
A U/Pb age for the Shetland Islands oceanic fragment, Scottish Caledonides: evidence from anatectic plagiogranites in ‘layer 3’ shear zones
复制标题
苏格兰喀里多尼德群岛设得兰群岛海洋碎片的 U/Pb 年龄：来自“第 3 层”剪切带深熔斜长花岗岩的证据
DOI：
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发表时间：
1991
影响因子：
2.3
通讯作者：
Gregory R. DUNNINGf
中科院分区：
文献类型：
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作者：
J. Spray;Gregory R. DUNNINGf
苏格兰东北部设得兰群岛大洋碎片辉长岩单元中斜长花岗岩中锆石的高精度U/Pb测年结果为492 ± 3 Ma。场关系表明，斜长花岗岩产生的高温剪切带内的角闪辉长岩的部分熔融形成的地壳变形和流体渗透发生在附近的扩展中心。因此，U/Pb数据限制了设得兰群岛杂岩的结晶年龄。这一年龄与挪威加里东山脉的Leka（497±2 Ma）、Karmoy（493 ± 7-4 Ma）和Gulfjellet（489±3 Ma）大洋碎片以及加拿大阿巴拉契亚山脉的管道石塘（4943-2 Ma）和贝茨湾（4893-2 Ma）大洋碎片的U/Pb年龄相似。
Abstract High precision U/Pb data obtained from zircons extracted from plagiogranite within the gabbro unit of the Shetland Islands oceanic fragment of northeast Scotland yield an age of 492 ± 3 Ma. Field relations indicate that the plagiogranites were generated by the partial melting of amphibolitized gabbros within high-temperature shear zones formed due to crustal deformation and fluid infiltration occurring in proximity to a spreading centre. The U/Pb data therefore constrain the crystallization age of the Shetland complex. This age is similar to U/Pb ages obtained from the Leka (497±2 Ma), Karmoy (493+7-4 Ma) and Gulfjellet (489±3 Ma) oceanic fragments of the Norwegian Caledonides, and the Pipestone Pond (4943-2 Ma) and Betts Cove (4893-2 Ma) oceanic fragments of the Canadian Appalachians.