Ca. 1.5 Ga mafic magmatism in South China during the break-up of the supercontinent Nuna/Columbia: The Zhuqing Fe–Ti–V oxide ore-bearing mafic intrusions in western Yangtze Block
Ca. 1.5 Ga mafic magmatism in South China during the break-up of the supercontinent Nuna/Columbia: The Zhuqing Fe–Ti–V oxide ore-bearing mafic intrusions in western Yangtze Block
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DOI：
10.1016/j.lithos.2013.02.004
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发表时间：
2013-05
期刊：
影响因子：
3.5
通讯作者：
Hong-Peng Fan;Weiguang Zhu;Zheng‐Xiang Li;H. Zhong;Z. Bai;D. He;Caiyun Chen;Chong-Yong Cao
中科院分区：
文献类型：
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作者：
Hong-Peng Fan;Weiguang Zhu;Zheng‐Xiang Li;H. Zhong;Z. Bai;D. He;Caiyun Chen;Chong-Yong Cao
本文报道了扬子地块西部朱庆含铁-钛-钒氧化物镁铁质岩体的二次离子质谱（西姆斯）锆石和斜锆石U-Pb年龄、元素和Nd同位素数据。镁铁质侵入体的锆石U-Pb年龄为1494± 6 Ma，斜锆石U-Pb年龄为1486± 3 Ma，斜锆石U-Pb年龄为1490± 4 Ma。侵入体主要是经历了不同程度的蚀变的辉长岩。研究岩石均为高钛碱性岩石，稀土元素轻富集，微量元素不相容模式呈“驼峰”状，Nb、Ta亏损不明显，与大陆溢流玄武岩（CFB）和洋岛玄武岩（OIB）区的板内碱性玄武岩相似。负εNd（T）值（−0.97 ~ −3.58）和重稀土元素分馏表明，这些岩石来自于时间积分的、轻微富集的软流圈地幔源区，并伴有轻微的地壳混染。与世界上其他与地幔柱有关的层状侵入体或大型火成岩省中的铁钛氧化物矿化岩一样，朱庆辉长岩可能产于板内环境。1.5Ga镁铁质岩浆活动可能是与努纳/哥伦比亚超大陆裂解有关的全球1.6-1.2Ga非造山岩浆活动的一部分，表明扬子地块可能是超大陆的一部分。
Secondary ion mass spectroscopy (SIMS) zircon and baddeleyite U–Pb ages, elemental, and Nd isotopic data are reported for the Zhuqing Fe–Ti–V oxide ore-bearing mafic intrusions in western Yangtze Block, South China. The mafic intrusions are dated at 1494±6Ma (zircon U–Pb), 1486±3Ma (baddeleyite U–Pb) and 1490±4Ma (baddeleyite U–Pb). The intrusions are dominantly gabbros that experienced variable degrees of alteration. All the studied rocks are high-Ti and alkaline in composition, and exhibit light rare earth element enrichment and “humped” incompatible trace-element patterns with no obvious Nb–Ta depletion, similar to intraplate alkali basaltic rocks in continental flood basalt (CFB) and ocean island basalt (OIB) provinces. Negative εNd(T) values (−0.97 to −3.58) and fractionation of the HREE of these rocks indicate that they were derived from a time-integrated, slightly enriched asthenospheric mantle source with minor crustal contamination. Like other Fe–Ti oxide mineralized rocks in plume-related layered intrusions or large igneous provinces around the world, the Zhuqing gabbros likely occurred in an intraplate setting. The ~1.5Ga mafic magmatism was likely part of the global 1.6–1.2Ga anorogenic magmatism related to the break-up of the supercontinent Nuna/Columbia, suggesting that the Yangtze Block may have been a component of the supercontinent.