欢迎访问现代地质!

现代地质 ›› 2025, Vol. 39 ›› Issue (03): 588-597.DOI: 10.19657/j.geoscience.1000-8527.2025.039

• 机器学习与矿物学应用 • 上一篇    下一篇

准噶尔盆地西北缘石炭系火山岩地球化学特征及其成因机制

牛花朋1,2(), 刘姗1,2, 焦小芹3, 张关龙4, 王千军4, 周健4, 赵贤1,2, 于洪洲4, 熊峥嵘4, 何晓1,2   

  1. 1.中国石油大学(北京)油气资源与工程全国重点实验室,北京 102249
    2.中国石油大学(北京)地球科学学院,北京 102249
    3. Department of Geosciences, University of Padova, Padua, Italy
    4.中国石油化工股份有限公司胜利油田分公司勘探开发研究院,山东 东营 257015
  • 出版日期:2025-06-10 发布日期:2025-07-03
  • 作者简介:牛花朋,女,博士,教授,1979年出生,主要从事矿物岩石学与储层地质学相关研究工作。Email:niuhuapeng@126.com
  • 基金资助:
    中国石油大学(北京)2024年度“学科前沿交叉探索专项”(2462024XKQY004);国家科技重大专项(2024ZD14049-004);中国石油化工股份公司项目(P22067)

Geochemical Characteristics and Petrogenesis of Carboniferous Volcanic Rocks in the Northwestern Margin of the Junggar Basin

NIU Huapeng1,2(), LIU Shan1,2, JIAO Xiaoqin3, ZHANG Guanlong4, WANG Qianjun4, ZHOU Jian4, ZHAO Xian1,2, YU Hongzhou4, XIONG Zhengrong4, HE Xiao1,2   

  1. 1. State Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum (Beijing), Beijing 102249, China
    2. College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China
    3. Department of Geosciences, University of Padova, Padua, Italy
    4. Research Institute of Exploration and Development, Sinopec Shengli Oilfield Company, Dongying, Shandong 257015, China
  • Published:2025-06-10 Online:2025-07-03

摘要:

本文选取准噶尔盆地西北缘哈拉阿拉特山(哈山)地区石炭系火山熔岩(玄武岩、玄武安山岩、安山岩)来说明其成因机制及构造背景。研究结果表明,三类岩石的MgO含量中等(3.21%~6.82%),Al2O3含量中等偏高(11.30%~17.78%),全碱K2O+Na2O含量较高(4.24%~7.24%)。其中,玄武岩样品整体K2O含量较低,体现 Na 相对于K 富集的特点,判断其为低钾拉斑系列玄武岩;玄武安山岩、安山岩的钙碱元素含量高,具有弧火山岩特征。三类火山岩整体呈现87Sr/86Sr值中等偏低(0.702877~0.706620)、εNd(t)同位素值(+4.59~+9.85)高的特征,表明岩浆在深部岩浆房经历了壳-幔混合作用。玄武安山岩、安山岩的稀土元素含量与玄武岩相比,大离子亲石元素Ba富集,高场强元素U、Pb相对富集、Nb亏损,表现出与俯冲消减带相关的岛弧岩浆作用的特点。通过与稀土、微量元素相关的构造环境分析,玄武岩含有源自亏损地幔的组分,低钾拉斑系列产于洋盆俯冲消减的构造背景,中性火山岩则刻度了大洋板块向大陆板块俯冲消减的过程,具体表现为亏损地幔楔受俯冲板块脱水释放的沉积物或洋壳熔体交代后,部分熔融形成玄武安山岩和安山岩。结合区域地质资料分析,准噶尔洋盆的俯冲消减可持续至晚石炭世。

关键词: 准噶尔盆地, 哈山, 石炭系, 火山岩, 岩石成因

Abstract:

This study investigates Carboniferous volcanic rocks (basalt, basaltic andesite, and andesite) from the Hara Arat Mountain (Hashan) area on the northwestern margin of the Junggar Basin to elucidate their petrogenesis and tectonic setting. Results indicate that these three rock types exhibit moderate MgO content (3.21%-6.82%), moderate to high Al2O3 content (11.30%-17.78%), and elevated total alkali content (K2O+Na2O=4.24%-7.24%). Basalt samples show relatively low K2O content, reflecting Na-enrichment relative to K, and are classified as low-K tholeiitic basalts. In contrast, basaltic andesites and andesites display high calc-alkaline element contents, consistent with island arc volcanic rock characteristics. Isotopic analyses reveal medium-low 87Sr/86Sr ratios (0.702877-0.706620) and high εNd(t) values (+4.59 to+9.85), indicating magma interaction between crustal and mantle components in a deep magma chamber. Compared to basalts, basaltic andesites and andesites show enrichment in large ion lithophile elements (e.g., Ba), relative enrichment in high field strength elements (e.g., U, Pb), and depletion in Nb, typical of subduction-related island arc magmatism. Trace element and rare earth element patterns suggest that basalts originated from depleted mantle melts under a convergent tectonic regime, while intermediate volcanic rocks record the subduction of oceanic plates beneath continental plates. This process involved the replacement of the depleted mantle wedge by sediments or melts derived from the dehydrating subducting slab, followed by partial melting to form basaltic andesites and andesites. Combined with regional geological data, the subduction of the oceanic plate persisted until the late Carboniferous.

Key words: Junggar Basin, Hashan, Carboniferous, volcanic rock, petrogenesis

中图分类号: