摘要:本文对新疆巴尔鲁克地区加曼铁列克得岩体花岗闪长岩进行了锆石U-Pb年代学、岩石地球化学和Sr-Nd-Hf同位素研究，探讨其岩石类型、构造背景和岩石成因。LA-ICP-MS锆石U-Pb定年表明，花岗闪长岩的成岩年龄为318.2±3.6 Ma，形成时代为晚石炭世。岩石高硅、富钠，碱含量中等，Mg#介于53.9～56.6，属于准铝质钙碱性花岗岩类（A/CNK = 0.91～0.97），轻重稀土分馏较明显且富集轻稀土（LaN/YbN = 8.55～10.10），Eu异常不明显，富集大离子亲石元素Ba、K、Sr，亏损高场强元素Nb、Ta、P、Ti。同位素特征显示，岩石具有低ISr值（0.703 82～0.704 24）、正εNd（t）值（+6.96～+7.74），年轻的tDM1值为0.74～0.61 Ga，锆石εHf（t）值为+12.6～+14.7，tDM2为519～396 Ma。综合地质、地球化学和年代学特征，认为加曼铁列克得花岗闪长岩为未分异的Ⅰ型花岗岩，形成于晚石炭世俯冲背景下的岛弧环境，可能是由流体参与的新元古代玄武质洋壳部分熔融的产物，岩浆上升过程中受到楔形地幔物质的混染。
关键词: 晚石炭世/
岛弧/
岩石成因/
加曼铁列克得岩体/
巴尔鲁克
Abstract:Zircon U-Pb chronology, Hf isotope, whole rock geochemistry and Sr-Nd isotopes are reported to discuss the petrogenesis and tetonic setting of the granodiorite in Jiamantieliek pluton, Barluck region, Xinjiang. LA-ICP-MS zircon U-Pb dating yields crystallization ages of 318.2±3.6 Ma for the granodiorite, indicating the pluton formed in Late Carboniferous. The rocks are characterized by high silicon, enrichment of sodium and relatively enriched in alkali, Mg# = 53.9～56.6, A/CNK = 0.91～0.97, belong to metaluminous calc-alkaline granite. The REEs are obviously fractionated with（La/Yb）N = 8.55～10.10 and weakly Eu anomaly. They are also enriched in LILE（Ba, K and Sr. etc.）and infertile in HFSE（Nb, Ta, P and Ti. etc.）. Sr-Nd isotopic compositions indicate that the granodiorite is characterized by positive εNd（t）（+6.96～+7.74）, low ISr（0.703 82～0.704 24） and relatively younger one-stage model ages（tDM1）ranging from 0.74～0.61 Ga. The?εHf（t）values and?tDM2 model ages of zircon are between +12.6 and +14.7, and 396 Ma and 519 Ma, respectively. Comprehensive geological, geochemical and chronological studies demonstrate that the granodiorite of Jiamantieliek pluton blongs to Ⅰ-tye granite. They formed in the island background during early subduction stage in the Late Carboniferous, Which derived from partial melting of subducted oceanic crust and subsequently undergone mantle wedge contamination during the upwelling process．
Key words:?Late Carboniferous/
Island arc/
Petrogenesis/
Jiamantieliek/
Barluck region
PDF全文下载地址:
http://www.dzkx.org/data/article/export-pdf?id=geology_11447
