塔里木盆地麦盖提斜坡皮山北新1井白云质角砾岩地层时代厘定

本文结合岩石薄片、古生物孢粉、同位素、铂族元素、野外露头剖面等资料，对塔里木盆地麦盖提斜坡皮山北新1井钻遇的一套白云质角砾岩地层时代进行了厘定。结果认为：6 884~7 068 m段归属古近系吐依洛克组，化石含量较少；7 068~7 150 m段归属白垩系依格孜牙组，孢粉化石丰富。该井古近纪与白垩纪地层界线深度7 068 m，该位置碳同位素的突变指示海洋环境的剧烈变化，这可以与全球K/E界线处对比。同时，铂族元素在该深度见到明显的异常，其含量明显增大，尤其以Rh、Ru、Ir、Os等最为明显。通过此次厘定，丰富了对麦盖提斜坡晚白垩世—古近纪早期沉积格局的认识。

Age Determination of Dolomite Breccia in Well PSBX1 of Markit Slope in Tarim Basin

The dolomitic breccia strata is drilled in Well PSBX1, Maigaiti slope, Tarim basin. Its age is determinated based on the data of thin section, paleontology sporopollen, isotope, platinum group elements and outcrop profiles. The results show that the 6 884-7 068 m well interval belongs to the Paleogene Tuyiluoke Group, which has very few fossils, 7 068-7 150 m well interval belongs to the Upper Cretaceous Yigeziya Group, which has a lots of sporopollen fossils. The Paleogene-Cretaceous boundary of this well lies at 7 068 m with an abrupt difference in carbon isotope, indicating a dramatic change of marine environment, which can be compared with the global K/E boundary. At this depth, the platinum group elements has obvious anormalies, their contents increase significantly, especially Rh, Ru, Ir, Os and so on. Through this determination, we have enriched our uderstanding of the sedimentary pattern of the Markit slope during the Late Cretaceous to the Early Paleogene.