| 王令全,陈丽娟.阿尔金造山带阿中地块塔什达坂西花岗岩体岩石地球化学特征、锆石U-Pb年龄及其地质意义[J].矿产勘查,2024,15(7):1125-1139 |
| 阿尔金造山带阿中地块塔什达坂西花岗岩体岩石地球化学特征、锆石U-Pb年龄及其地质意义 |
| Geochemical characteristics， zircon U-Pb dating and the geological significance of West Tashdaban granite pluton in the Azhong Block of Altyn Orogen |
| 投稿时间：2024-06-09 修订日期：2024-07-05 |
| DOI：10.20008/j.kckc.202407001 |
| 中文关键词: 岩石地球化学 锆石U-Pb定年 阿中地块 塔什达坂西 花岗岩 |
| 英文关键词: geochemical characteristic zircon U-Pb dating Azhong block western of Tashdaban granite |
| 基金项目:本文受新疆地质勘查基金项目管理中心“新疆阿尔金塔什达坂一带1∶5万J45E008021、J45E008022、J45E008023 三幅区域地质矿产调查（K15-1-LQ11）”项目资助。 |
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| 中文摘要: |
| 分布于阿尔金造山带阿中地块北缘中新元古界隆起带的库木达坂岩体，为一规模较大的复式岩体。近年来，随着一批以黄龙岭超大型锂矿床为代表的、围绕该岩体产出的大中型锂矿床的发现，使得该区成为新的找矿热点区带。笔者在1∶5万区域地质调查中从原库木达坂岩体解体出的新侵入体，该岩体位于塔什达坂西，岩性以粗粒二云母二长花岗岩为主。前人关于该岩体的研究较少，本文通过对岩体进行岩石学、岩石地球化学、同位素年代学研究，探讨该岩体岩浆作用及地质意义。研究表明，塔什达坂西花岗岩体具高硅、富钾、相对贫钠特征，铝饱和指数大于1.1，属过铝质高钾钙碱性花岗岩系列。稀土元素总量较低，轻稀土元素相对富集、重稀土元素亏损，有右倾型特征和明显的负Eu异常。富集Rb、Th、U、K等大离子亲石元素，亏损Ba、Sr、Ti等，具典型S型花岗岩特征。推断其是在温度为~726°C，压力＜8 kbar的条件下，由地壳泥质岩系部分熔融的产物。粗粒二云母二长花岗岩锆石U-Pb年龄为（466.5±3.0）Ma，侵位时代为中奥陶世。岩体形成于同碰撞构造环境，推断其为南阿尔金洋闭合后陆-陆碰撞的产物。 |
| 英文摘要: |
| The Kumdaban pluton， distributed in an uplift belt of the Meso-Neoproterozoic strata on the northern margin of the Azhong block of the Altyn orogenic belt， is a large-scale composite pluton. In recent years， with the discovery of a number of large and medium-scaled lithium deposits represented by the Huanglongling super-large lithium deposit around this pluton， making the area a new hotspot for mineral exploration. The author identified a new intrusion during a 1∶50，000 regional geological survey， which was separated from the original Kumdaban pluton. It is located western of Tashdaban， with the main lithology being coarse-grained two-mica monzogranite. There has been relatively little research on this pluton. This paper explores the magmatism and geological significance of the pluton through petrology， geochemistry， and isotope geochronology research. The study shows that the granite in the western Tashdaban is characterized by high SiO2， K2O and relatively low Na2O， with aluminum saturation index values greater than 1.1， belonging to the peraluminous high-K calc-alkaline granite series. In addition， the total amount of rare earth elements is low， with a relative enrichment of light rare earth elements and a deficit of heavy rare earth elements， exhibiting a right-sloping type and a significant negative Eu anomaly. It is enriched in large ion lithophile elements such as Rb， Th， U， K， etc.， and depleted in Ba， Sr， Ti， etc.， showing typical characteristics of S-type granites. It is inferred that it was formed under conditions of ~726°C temperature and pressure <8kbar， from partial melting of crustal pelitic rock series. The zircon U-Pb age of the coarse-grained two-mica monzogranite is （466.5±3.0） Ma， indicating an emplacement era in the Middle Ordovician. The pluton was formed in a syn-collisional tectonic setting， and it is inferred to be the product of the continent-continent collision after the closure of the South Altyn Ocean. |
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