SHRIMP U–Pb zircon dating of the Neoproterozoic Penglai Group and Archean gneisses from the Jiaobei Terrane, North China, and their tectonic implications
SHRIMP U–Pb zircon dating of the Neoproterozoic Penglai Group and Archean gneisses from the Jiaobei Terrane, North China, and their tectonic implications
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DOI：
10.1016/j.precamres.2007.08.004
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发表时间：
2008-02
影响因子：
3.8
通讯作者：
Jian‐Bo Zhou;S. Wilde;Guochun Zhao;Changqing Zheng;W. Jin;Xingzhou Zhang;Hongjiang Cheng
中科院分区：
文献类型：
--
作者：
Jian‐Bo Zhou;S. Wilde;Guochun Zhao;Changqing Zheng;W. Jin;Xingzhou Zhang;Hongjiang Cheng
华北克拉通东南缘交北地体发育太古宙基底片麻岩、上壳岩和新元古代（震旦系）变质沉积岩（蓬莱群）。太古宙TTG片麻岩SHRIMP U-Pb年龄为2541±5Ma，新元古代蓬莱群变质沉积岩锆石年龄为2.9 ~ 1.8Ga。锆石大致可分为2.0 ~ 1.8 ga、2.45 ~ 2.1 ga和> ~ 2.5Ga三个年龄群。年龄为bb0 ~ 2.6Ga的碎屑锆石颗粒数量较少，年龄<1.8Ga的碎屑锆石颗粒均无。这些结果表明，大部分碎屑物质来自古元古代，最可能来自尖山群和粉子山群，部分碎屑物质来自焦北地体太古代片麻岩。角闪岩相角闪斜长片麻岩年龄为1866±4Ma，是太古宙TTG片麻岩的上壳层序的一部分，显示晚古元古代变质作用。太古宙片麻岩杂岩和蓬莱变质沉积岩与先前描述的胶辽基造山带组分相似，表明胶北地体具有华北克拉通的亲缘性；它们还表明，沿胶辽基带的碰撞时间为~ 1865Ma。
Archean basement gneisses and supracrustal rocks, together with Neoproterozoic (Sinian) metasedimentary rocks (the Penglai Group) occur in the Jiaobei Terrane at the southeastern margin of the North China Craton. SHRIMP U–Pb zircon dating of an Archean TTG gneiss gave an age of 2541±5Ma, whereas metasedimentary rocks from the Neoproterozoic Penglai Group yielded a range in zircon ages from 2.9 to 1.8Ga. The zircons can be broadly divided into three age populations, at: 2.0–1.8Ga, 2.45–2.1Ga and >2.5Ga. Detrital zircon grains with ages >2.6Ga are few in number and there are none with ages <1.8Ga. These results indicate that most of the detrital material comes from a Paleoproterozoic source, most likely from the Jianshan and Fenzishan groups, with some material coming from Archean gneisses in the Jiaobei Terrane. An age of 1866±4Ma for amphibolite-facies hornblende–plagioclase gneiss, forming part of a supracrustal sequence within the Archean TTG gneiss, indicates Late Paleoproterozoic metamorphism. Both the Archean gneiss complex and Penglai metasedimentary rocks resemble previously described components of the Jiao-Liao-Ji orogenic belt and suggest that the Jiaobei Terrane has a North China Craton affinity; they also suggest that the time of collision along the Jiao-Liao-Ji Belt was at ∼1865Ma.