柴达木盆地北缘全吉群皱节山组碎屑锆石年代学特征及其地质意义
Detrital Zircon Geochronology and Geological Significance of Zhoujieshan-Formation,Quanji Group in North Margin of Qaidam Basin

柴达木盆地北缘的全吉群主要为一套未变质的砂砾岩、石英岩、砂页岩、白云岩和冰碛岩的地层，为全吉地块基底之上的最古老的直接沉积盖层.对全吉群上部皱节山组2件紫红色细砂岩样品进行碎屑锆石LA-ICP-MS U-Pb年龄测定，碎屑锆石 207Pb/ 206Pb年龄谱特征显示，皱节山组沉积物主要以1750~1990Ma(约占84.7%)的锆石年龄最为集中，其次为2 400~2 500Ma的年龄值，结合区域热事件，说明皱节山组沉积物可能主要来自于全吉地块古元古代末达肯大坂岩群，部分来自德令哈杂岩体.此外，~1.95 Ga和~1.85 Ga的碎屑锆石具有显著优势，它记录了全吉地块在古元古代的2期重要的热事件——古元古代末镁铁质岩墙群的侵入作用和古元古代晚期的区域变质-深熔作用.
The Quanji Group is mainly distributed in the north margin of Qaidam basin and consists of non-metamorphic sandstone, quartzite, sand shale, dolomite and tillite. U-Pb ages of detrital zircons from two sandstone samples in the Zhoujieshan Formation in the Upper Quanji Group were measured using the LA-ICP-MS method. The concordant ages of detrial zircons show that the provenance in the Zhoujieshan Formation was derived mainly from the Dakendaban Group of the Quanji block (1750-1990 Ma), subordinately from the Delingha complex (2 400-2 500 Ma). In addition, the detrital zircons record two important thermal events (~1.95 Ga and ~1.85 Ga) of the Quanji block in Paleoproterozoic—strong regional metamorphism and anatexis, with magmatic intrusion