| 黄鑫,杨镜明,王忠阳.新疆色尔特能地区超镁铁岩岩石地球化学特征及构造环境分析[J].地质找矿论丛,2021,36(4):466-474 |
| 新疆色尔特能地区超镁铁岩岩石地球化学特征及构造环境分析 |
| Geochemical characteristics and tectonic setting of ultra basic rocks in Serteneng area, Xinjiang |
| 投稿时间：2021-04-29 修订日期：2021-09-01 |
| DOI：10.6053/j.issn.1001-1412.2021.04.008 |
| 中文关键词: 色尔特能地区 超镁铁质岩 岩石地球化学 洋内弧后盆地 康古尔韧性剪切带 新疆 |
| 英文关键词:Serteneng area ultra-basic rock petrogeochemistry intra-ocean back-arc basin Kanggur ductile shear belt Xinjiang |
| 基金项目:核工业地质局铀矿地质项目（编号：2020-024）资助。 |
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| 中文摘要: |
| 通过对出露在康古尔韧性剪切带西段的色尔特能超镁铁岩的野外地质调查和岩石学、岩石地球化学方面的分析研究工作，结果显示：色尔特能超镁铁岩发生了强烈蛇纹石化，基本蚀变成蛇纹岩；岩石主量元素具高Mg （w（MgO）=36.15%~37.96%）、高Cr （w（Cr2O3）=0.32%~0.36%）、高Ni （w（NiO）=0.17%~0.21%）、低Si （w（SiO2）=40.50%~41.92%）、贫Al （w（Al2O3）=1.19%~1.77%）、低Fe （w（TFeO）=6.98%~7.87%）特征，Mg#值为94.71~97.73，m/f值为8.03~9.42，属于典型镁质超镁铁岩，推测原岩为斜方辉石橄榄岩；稀土元素总量w（ΣREE）=1.44×10-6~2.92×10-6，配分模式为轻稀土微弱富集近平坦型，w（La）N/w（Yb）N=3.09~5.49，具一定程度的负Eu异常（δEu=0.48~1.09）和负Ce异常（δCe=0.53~0.60）；微量元素富集Ba、U、Ta，亏损Nb、Ti。色尔特能超镁铁岩属变质橄榄岩，是SSZ型蛇绿岩的底部组成单元，由原始地幔经2%~10%部分熔融形成的亏损地幔岩，其形成于俯冲带环境中的洋内弧后盆地。 |
| 英文摘要: |
| Field investigation, petrological and geochemical study of Serteneng ultra-basic rocks in the West Kanggur ductile shear zone were completed. The ultra-basic rocks are intensely altered almostly to serpentinite. Major elements of them is characterized by high Mg, Cr, Ni (w(MgO)=36.15%-37.96%, w(Cr2O3)=0.32%-0.36%, w(NiO)=0.17%-0.21%) and low Si(SiO2=40.50%~41.92%),depletion of Al(w(Al2O3)=1.19%-1.77%) and low Fe(w(TFeO)=6.98%-7.87%). Mg# value is 94.71-97.73, m/f value 8.03-9.42, the indication of magnesium ultra-basic rock. The original rock may be harzburgite. REE analysis is characterized by extremely low REE (w(ΣREE)=1.44×10-6-2.92×10-6), the normalized REE pattern by nearly flat (weak enrichment, w(La)N/w(Yb)N=3.09-5.49, slightly negative Eu anomaly (δEu=0.48-1.09) and significant negative Ce anomaly (δCe=0.53-0.60). Trace element is characterized by enrichment of Ba, U, Ta, etc. depletion of Nb, Ti. The ultra-basic rocks are metamorphosed peridotite at bottom of SSZ type ophiolite derived from depleted mantle of partially melted (2%-10%) original mantle. They were formed in the intra-ocean back-arc basin setting at the subduction zone. |
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