MEI Sheng-wang1,2,3, WANG Yu-mei4, DU Xian-feng1,5, CHI Hong-xing1, GUO Pu1, ZHANG Ming-feng6, WANG Xian-bin6, ZHUO Sheng-guang1
1. The School of Resource and Material, Northeastern University at Qinhuangdao, Qinhuangdao 066000, China;
2. State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;
3. University of Chinese Academy of Sciences, Beijing 100049, China;
4. Daqing Oilfield Downhole Operation Company, Daqing, Daqing 163453, China;
5. China University of Geosciences(Beijing), Beijing 100083, China;
6. Key Laboratory of Petroleum Resources, Gansu Province/Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China
Abstract: In order to discuss genetic significance of the serpentinized peridotite in the Wenduermiao area, Inner Mongolia, China, many representative serpentinized peridotite samples have been selected to analyze their major, trace, and REE elements by using XRF and ICP-MS methids. Results show that serpentinized peridotites have higher MgO but lower CaO, Al2O3, TiO2 contents than those of the primitive mantle, with negative correlations between their MgO contents and respective CaO, Al2O3, TiO2 contents. This implies that the peridotite in the Wenduermiao area could be the residue of partial melting of the depleted primary mantle. Their REE and trace elements distribution patterns show that LREE are slightly enriched, some LILE(Rb) are obviously depleted, while some HFSE(U、Pb、Hf) are strongly enriched. These features imply that they could be related not only to the mantle source, but alsoto the metasomatism of the subduction zone fluid or the serpentinization of the peridotite. Additionally, the mantle peridotite was derived from the partial melting of a spinel phase mantle. Based on the partial melting model established by Melcher, it is suggested that the Wenduermiao peridotite was originated by partial melting of 5%~20% of the spinel phase mantle, similar to those of the abysmal sea mantle peridotite. All above features imply that the peridotite of the Wenduermiao ophiolite could be formed in a MOR setting and then modified by fluids in a SSZ setting.
Keywords: serpentinization mantle peridotite ophiolite wenduermia
E-Mail: sgzhuo@sina.com
Bulletin of Mineralogy, Petrology and Geochemistry Vol.35, No.2, 2016, page 212-221
