新疆石油地质

新疆石油地质 ›› 2003, Vol. 24 ›› Issue (4): 284-285.

• 油气勘探 • 上一篇    下一篇

巴楚瓦基里塔格基性-超基性杂岩40Ar-39Ar定年

宋文杰1,2, 李日俊1,2, 胡世玲1, 郭宏2, 黄智斌2, 郑多明2   

  1. 1.中国科学院 地质与地球物理研究所,北京 100029;
    2.中国石油 塔里木油田分公司,新疆 库尔勒 841000
  • 收稿日期:2002-08-29 修回日期:2002-11-28 发布日期:2021-01-13
  • 作者简介:宋文杰(1963-),男,山东人,高级工程师,石油地质学和构造地质学专业。联系电话:0996-2171411
  • 基金资助:
    “国家自然科学基金课题（批准号40072077)和塔里木油田科技攻关项目(41301050336)

Restudy on the 40Ar-39Ar Age of Wajilitag Basic-Ultrabasic Complex in Western Tarim Basin

SONG Wen-jie1,2, LI Yue-jun1,2, HU Shi-ling1, GUO Hong2, HUANG Zhi-bing2, ZHENG Duo-ming2   

  1. 1. Research Institute of Geology and Geophysics, CAS, Beijing 100029, China;
    2. Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000, China
  • Received:2002-08-29 Revised:2002-11-28 Published:2021-01-13

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摘要： 瓦基里塔格位于新疆塔里木盆地中央隆起的西部,巴楚县城南东约40km.这里发育一套轻微变质的碎屑岩哑地层,其中出露有一套基性-超基性杂岩。在该杂岩中曾获得辉长岩40Ar-39Ar年龄为821×106～837×106a.这组年龄数据是首次在塔里木盆地腹地获得的较可靠的前寒武纪同位素年龄资料。鉴于对该杂岩及其围岩时代的认识存在明显分歧,再次在该杂岩中采集闪长岩样品进行40Ar-39Ar定年,得到闪长岩40Ar-39Ar坪年龄为879.12×106a±1.47×106a,相应的等时年龄为881.34×106a±18.82×106a,反等时线年龄为880.35×106a±1.22×106a.这一测试结果进一步证明瓦基里塔格基性-超基性杂岩形成于前寒武纪,是塔里木盆地前寒武纪基底的组成部分。

关键词: 塔里木盆地, 巴楚, 瓦基里塔格, 闪长岩, 39Ar-40Ar定年, 前寒武纪

Abstract: Wajilitag structure, about 40km southeast to Bachu county, is located at western Tazhong uplift, Tarim basin. There exists a set of slightly metamorphic unfossiliferous clastic rocks at Wajilitag where a developed basic-ultrabasic complex is outcropped. Although the gab-bro 40Ar-39Ar age of 821~837Ma was obtained from this complex in 1999, which was the first dating of Precambrian isotopic age in hinterland of Tarim basin, ages of this complex and its surroundings are still questionable. In order to validate the prev ious results, re-collected gabbro samples are used for 40Ar-39Ar dating from it, obtaining its plateau age of 879. 12+1.47Ma, corresponding isochronal age of 881.34t 18.82Ma and reverse isochronal age of 880.351 1.22Ma. These measurements indicate that Wajilitag basic-ultrabasic complex was formed in Precam-brian, belonging to a part of Precambian basement in Tarim basin. This conclusion is also supported by related petrochemical analysis, that is, Tarim basin possesses ancient continental crust basement.The magnetic rocks and Palaeozoic strata in Buchu area (including Wajilitag structure) are possibly basement outcrops. This study could be as a guide for hydrocarbon prospecting in Wajilitag structure.

Key words: Tarim basin, Bachu area, Wajilitag, gabbro, 40Ar-39Ar dating, Precambrian

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