Neoproterozoic Arc‐Related Mafic Intrusions along the Northern Margin of South China: Implications for the Accretion of Rodinia
Neoproterozoic Arc‐Related Mafic Intrusions along the Northern Margin of South China: Implications for the Accretion of Rodinia
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DOI：
10.1086/341762
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发表时间：
2002-09
期刊：
影响因子：
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通讯作者：
Mei‐Fu Zhou;A. Kennedy;M. Sun;J. Malpas;C. Lesher
中科院分区：
文献类型：
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作者：
Mei‐Fu Zhou;A. Kennedy;M. Sun;J. Malpas;C. Lesher
在新元古代，南中国一直被认为是罗德尼超大陆的一部分，尽管它在这个超级大陆中的古地理位置仍然是一个有争议的问题。南中国北缘的望江山杂岩和碧鸡沟杂岩是中国最大的镁铁质侵入岩之一。新的SHRIMP锆石U-Pb结果表明，这两个侵入岩的结晶年龄分别为820 Ma和780 Ma。这些侵入岩中大离子亲石元素和轻稀土元素的富集以及高场强元素的亏损表明它们来自大陆边缘的活动弧。这种将这些侵入岩解释为大陆弧组合的一部分，与以前的观点形成鲜明对比，即它们是新元古代地幔热柱的产物，启动了罗迪尼亚的解体。新元古代岩浆弧的存在表明，罗丁纪大洋岩石圈被俯冲到南中国北缘(今)之下，因此，南中国位于罗德尼洋的两侧。
South China has been considered as part of the Rodinian supercontinent during Neoproterozoic time, although its paleogeographic position within this supercontinent is still a matter of debate. The Wangjiangshan and Bijigou complexes along the northern margin of South China are among the largest mafic intrusions in China. New SHRIMP zircon U‐Pb results indicate that these two intrusions have crystallization ages of 820 Ma and 780 Ma, respectively. Enrichment of large ion lithophile and light rare earth elements and depletion of high field‐strength elements in these intrusions suggest derivation from an active arc along a continental margin. This interpretation of these intrusions as part of a continental arc assemblage is in contrast with the previous view that they were products of a Neoproterozoic mantle plume that initiated the breakup of Rodinia. The presence of a Neoproterozoic magmatic arc suggests that Rodinian oceanic lithosphere was subducted beneath the (present) northern margin of South China and therefore that South China flanked the Rodinian ocean.