Elemental and Sr-Nd isotopic geochemistry of the basalts and microgabbros in the Shuanggou ophiolite, SW China: implication for the evolution of the Palaeotethys Ocean

	Elemental and Sr-Nd isotopic geochemistry of the basalts and microgabbros in the Shuanggou ophiolite, SW China: implication for the evolution of the Palaeotethys Ocean
	WEN-JUN HU; HONG ZHONG; WEI-GUANG ZHU; XIAO-HU HE
	2015
发表期刊	Geological Magazine
卷号	152 期号:2 页码:210-224
摘要	The Early Palaeozoic Shuanggou ophiolite is the best-preserved part of the Ailaoshan ophiolite belt. The microgabbros (basaltic dykes) and basalts (basaltic lavas) show distinct characteristics in geochemistry, implying that their genetic mechanisms are different. With Al2O3 contents ranging from 14.7% to 17.0%, the microgabbros belong to low-alumina type. They exhibit normal mid-ocean-ridge basalt (N-MORB) -like trace elemental characteristics with positive epsilon(Nd)(t) values (9.7-11.6) and slightly variable (Sr-87/Sr-86)(i) ratios (0.7036-0.7046). In contrast, the basalts have high Al2O3 contents (19.5-23.2%), therefore belonging to high-alumina type. A plagioclase-accumulation model is used to account for the high alumina contents. Moreover, the basalts have enriched MORB (E-MORB) -like trace element characteristics with lower epsilon(Nd)(t) values (6.4-8.0) and (Sr-87/Sr-86)(i) ratios (0.7032-0.7036). Their incompatible element ratios exhibit linear correlation with the isotopic data, which is probably related to the contribution of a mixed lithosphere-asthenosphere source. In summary, a two-stage model is proposed to explain the formation of the Shuanggou ophiolite: (1) at the continent-ocean transition stage, the basalts were generated by low-degree partial melting of the mixed mantle near a slow-spreading embryonic centre; and (2) at the mature stage of the Ailaoshan Ocean, the microgabbros were produced by moderate-degree partial melting of the depleted asthenospheric mantle.
学科领域	矿床地球化学
收录类别	SCI
语种	英语
文献类型	期刊论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/5962
专题	矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文
推荐引用方式 GB/T 7714	WEN-JUN HU,HONG ZHONG,WEI-GUANG ZHU,et al. Elemental and Sr-Nd isotopic geochemistry of the basalts and microgabbros in the Shuanggou ophiolite, SW China: implication for the evolution of the Palaeotethys Ocean[J]. Geological Magazine,2015,152(2):210-224.
APA	WEN-JUN HU,HONG ZHONG,WEI-GUANG ZHU,&XIAO-HU HE.(2015).Elemental and Sr-Nd isotopic geochemistry of the basalts and microgabbros in the Shuanggou ophiolite, SW China: implication for the evolution of the Palaeotethys Ocean.Geological Magazine,152(2),210-224.
MLA	WEN-JUN HU,et al."Elemental and Sr-Nd isotopic geochemistry of the basalts and microgabbros in the Shuanggou ophiolite, SW China: implication for the evolution of the Palaeotethys Ocean".Geological Magazine 152.2(2015):210-224.

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