| 塔河地区海西晚期火山岩地球化学特征及地质意义 |
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| 引用本文： | 崔泽宏,唐 跃.塔河地区海西晚期火山岩地球化学特征及地质意义[J].中国地质,2010,37(2):334-346. |
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| 作者姓名： | 崔泽宏 唐 跃 |
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| 作者单位： | 1. 中国石油勘探开发研究院,北京,100083;中国石油大学盆地与油藏研究中心,北京,102249
2. 中国地质调查局发展研究中心,北京,100037 |
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| 基金项目： | 国家重点基础研究发展规划(973计划) |
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| 摘 要： | 通过岩心观察,塔河地区海西晚期先后发育基性火山岩和中酸性火山岩两大类。两类火山岩具有不同地球化学组成:基性火山岩K2O+Na2O=3.49%~4.25%,K2O/Na2O=0.18~0.381,为钠质系列玄武岩,富集大离子亲石元素K、Rb、Ba、Th和高场强元素Nb、Ta、Ti、Zr、P,δEu≈1,无明显亏损;中酸性火山岩表现为高场强元素Nb、Ta、Sr、P、Ti亏损,大离子亲石元素K、Rb、Ba、Th较为富集,稀土元素δEu=0.43~0.661,铕具明显负异常特征,K2O+Na2O=6.86%~8.82%,K2O/Na2O=1.25~1.591,为钾玄或高钾钙碱性系列英安岩。强不相容元素Th/Ta、Nb/U比值说明,玄武岩与英安岩成因没有明显亲缘性,玄武岩来源于地幔,英安岩来源于地壳。结合邻区火成岩对比分析,塔河地区发育的玄武岩、英安岩分别与塔中地区玄武岩和南天山分区花岗岩具有相同的地球化学特征,构造判别图解表明,玄武岩形成于板内主裂陷期,英安岩、花岗岩形成于板块边缘岛弧构造环境,作为特殊古构造位置,塔河地区先后发育的玄武岩、英安岩为板内主裂陷盆地边缘和弧火山边缘相互耦合的产物。
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| 关 键 词： | 玄武岩 英安岩 地球化学 构造环境 地质意义 |
Geochemical characteristics and geological significance of Late Hercynian volcanic rocks in Tahe area |
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| CUI Ze-hong,TANG Yue.Geochemical characteristics and geological significance of Late Hercynian volcanic rocks in Tahe area[J].Chinese Geology,2010,37(2):334-346. |
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| Authors: | CUI Ze-hong TANG Yue |
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| Institution: | 1. Research Institute of Petroleum, PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China;2. Basin & Reservoir Research Center, China University of Petroleum, Beijing 102249, China; 3. Development and Research Center, China Geological Survey, Beijing 100037, China |
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| Abstract: | Core observation shows that mafic volcanic and intermediate-acidic volcanic rocks were developed successively in Tahe area in Late Hercynian. These two types of volcanic rocks have different geochemical compositions. In mafic volcanic rock, K_2O+Na_2O=3.49%～4.25%,K_2O/Na_2O=0.18～0.38<1, large-ion lithophile elements (LILE) K, Rb, Ba, Th and high-field strength elements (HFSE) Nb, Ta, Ti, Zr, P are high, and δEu ≈ 1, with no significant anomaly, suggesting that this type of volcanic rock belongs to the sodic series basalt As for intermediate-acidic volcanic rock, K_2O+Na_2O= 6.86%～8.82%,K_2O/Na_2O=1.25～1.59>l, HFSE Nb, Ta, Sr, P, Ti are poor, LILE K, Rb, Ba, Th are high, and δ Eu=0.43～0.66
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| Keywords: | basalt dacite geochemistry tectonic setting geological significance |
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