二连盆地哈达图地区赛汉组上段碎屑锆石U-Pb年龄及地质意义

U-Pb Geochronology of Detrital Zircons From the Upper Member of Saihan Formation and its Geological Implications in Hadatu Area,Erlian Basin

选取二连盆地哈达图地区的主要赋矿层位赛汉组上段开展碎屑锆石年代学研究,结果显示,LA-ICP-MS锆石U-Pb年龄以170~120 Ma和290~220 Ma为主,其次为327~310 Ma、430~410 Ma和472~444 Ma等。盆地地质特征、古河道特征以及碎屑锆石年代学数据表明,哈达图地区南部苏尼特隆起中的早二叠-晚三叠世和中侏罗-早白垩世岩浆岩不仅为赛汉组上段提供了碎屑物质,而且很可能提供了一定的成矿物质。

Detrital zircons from the upper member of Saihan Formation in Hadatu area have been dated by LA-ICP-MS.The results showed that detrital zircons from two samples exhibit two predominant age groups(i.e.,170~120 Ma and 290~220 Ma)and several subordinate age populations(i.e.,327~310 Ma,430~410 Ma,472~444 Ma).Based on the new ages and geological features,we argue that the provenance of the upper member of Saihan Formation in Hadatu area dominantly derived from the Early Permian to Late Triassic and Middle Jurassic to Early Cretaceous igneous rocks occurred in the Sunite horsts of the southern Hadatu area.These igneous rocks supplied the debris and even some ore-forming materials for the upper member of Saihan Formation during the deposition processes.