| 王孜悦.新疆哈图—包古图地区侵入岩岩石学和地球化学特征研究[J].甘肃地质,2025,(1):1-12 |
| 新疆哈图—包古图地区侵入岩岩石学和地球化学特征研究 |
| Petrology and Geochemistry of the Intrusive Rocks in Hatu-Baogutu Area of Xinjiang |
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| DOI： |
| 中文关键词: 西准噶尔 中酸性侵入岩 成因类型 岩浆源区 构造环境 |
| 英文关键词:West Junggar intermediate acid intrusive rock genetic type magma source area tectonic environment |
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| 中文摘要: |
| 新疆西准噶尔哈图—包古图地区分布着大量中酸性侵入岩，主要岩性为闪长岩、花岗闪长岩及花岗岩，造岩矿物以斜长石、角闪石、黑云母和石英为主。本文结合前人研究成果对这些侵入岩进行了年代学、岩石学和地球化学研究。结果显示，哈图—包古图侵入岩的SiO2含量介于46. 00% ~ 76. 94%之间，属于中酸性岩类。岩石具有高K2O（0. 53% ~ 6. 16%）、高CaO（0. 19% ~ 11. 45%）、高Na2O（2. 66% ~ 5. 90 %）特征，为钙碱性—高钾钙碱性岩石，属于过铝质系列。侵入岩稀土元素总量变化范围为63. 70 × 10-6 ~ 342. 94 × 10-6，轻稀土富集，重稀土平坦分布，显示右倾型稀土配分模式。大离子亲石元素含量变化范围较大，富集Cs、U，亏损Rb、Th、Nb。根据地质年代学，将侵入岩在时间上分为了三个阶段：晚志留世（415 ~ 420 Ma），早石炭世末—晚石炭世初（315 ~ 320 Ma），晚石炭世—早二叠世（295 ～ 315 Ma）。西准噶尔晚志留世形成A型花岗岩岩浆源区为新生下地壳的部分熔融，可能处于板片窗口洋脊俯冲时期；早石炭世末—晚石炭世初形成的I型花岗岩岩浆源区为亏损地幔，可能遭受中上地壳同化混染作用，处于洋脊俯冲环境；晚石炭世—早二叠世形成I型和A型花岗岩岩浆源区可能来源于亏损地幔或新生下地壳的部分熔融，可能处于洋脊俯冲环境与碰撞后伸展环境之间的过渡阶段，同时存在大规模地幔热柱上涌事件。 |
| 英文摘要: |
| A large number of intermediate acid intrusive rocks are distributed in Hatu Baogutu area, western Junggar, Xinjiang. The main lithology is diorite, granodiorite and granite. The rock forming minerals are mainly plagioclase, amphibole, biotite and quartz. Combined with the previous research results, this paper studies the chronology, petrology and geochemistry of these intrusive rocks. The results show that the SiO2 content of Hatu Baogutu intrusive rock is 46. 00% ~ 76. 94% It belongs to medium acid rocks. The rock is characterized by high K2O（0. 53% ~ 6. 16%）, high CaO（0. 19% ~ 11. 45%） and high Na2O（2. 66% ~ 5. 90%）, which is calc alkaline high potassium calc alkaline rock, belonging to peraluminous series. The variation range of total rare earth elements in intrusive rocks is 63. 70 × 10-6 ~ 342. 94 × 10-6, light rare earth enrichment, heavy rare earth flat distribution, showing a right inclined rare earth distribution mode. The content of large ion lithophile elements varies widely, enriching Cs and U and losing Rb, Th and Nb. According to geochronology, the intrusive rocks are divided into three stages in time: Late Silurian（415 ~ 420 Ma）, end of Early Carboniferous-beginning of Late Carboniferous （315 ~ 320 Ma）, Late Carboniferous-Early Permian （295 ~ 315 Ma）. In the late Silurian （415 ~ 420 Ma）, the magma source of A-type granites in the Western Junggar was partial melting of the juvenile lower crust, possibly during a period of oceanic ridge subduction through a slab window. At the end of the Early Carboniferous to the beginning of the Late Carboniferous （315 ~ 320 Ma）, the magma source of I-type granites was the depleted mantle, which may have undergone assimilation and contamination by the middle and upper crust, occurring in an oceanic ridge subduction environment. During the Late Carboniferous to the Early Permian （295 ~ 315 Ma）, the magma sources of I-type and A-type granites may have originated from partial melting of the depleted mantle or juvenile lower crust, possibly in a transitional stage between oceanic ridge subduction and post-collisional extensional environments, with large-scale mantle plume upwelling events also present. |
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