吐鲁番拗陷二叠系─三叠系烃源岩研究

以地表剖面暗色泥岩的有机地球化学分析资料为主，结合部分井下烃源岩样品分析数据，研究了吐鲁番拗陷二叠系－三叠系暗色泥岩的有机质丰度、有机质类型及有机质成熟度特征，并分析了控制烃源岩生烃条件的影响因素。     

Advance in the study of the Lower Triassic conodonts at Meishan Section, Changxing, Zhejiang Province

Meishan Section in Changxing County of Zhejiang Province is one of the four candidates of the global stratotype section and point (GSSP) of the Permian and Triassic boundary (PTB), and currently the conodonts have been widely accepted as the index fossils to define the Permian and Triassic boundary. The previous studies on the Lower Triassic conodonts at Meishan Section are summarized and the recent discovery of the Lower Triassic conodonts there is reported. The recognized data from the section indicate that Meishan is the best selection of the GSSP of PTB.     

Gymnosperms on the eve of the terminal Permian mass extinction in North China and their survival strategies

Main characteristics of the Permian redbed gymnmprms in North China have been summarized: dominant peltasperms and conifers, numerous enigmatics such asGigantonoclea andPsygmophyllum, and abundant precursors of Mesozoic gymnosperm. Furthermore, stresses affecting these plants survival are suggested to be paleoatmospheric CO₂ concentration, water stress, wind and fire activities, und fungal infection. Consequently, a preliminary analysis accounts for the ecological strategies of these gymnosperms to the P-Tr event.     

鲁西地区早二叠世早、中期孢粉组合特征

为解决鲁西地区二叠系内部划分和煤层对比问题，笔者先后对鲁西诸煤田二叠系进行了大量的孢粉分析工作，采集处理300多块样品，经系统研究，建立了本区二叠纪的4个孢粉组合，本文重点讨论早二叠世早、中期的两个孢粉组合，自下而上为：Thymospora thiessenii-Laevigatosporites vulgaris-Densosprites组合；Gulisporites cochlearius-Laevigatosposporites组合。根据所建立的各孢粉组合特征并与华北各地二叠纪孢粉组合广泛对比，进一步阐述了各孢粉组合的地质时代。     

Discovery of marine fossils in the upper part of the Permian Linxi Formation in Lopingian, Xingmeng area, China

Two important geological issues have a long history of debate in the Xingmeng area. The first concerns the final closure of the North China plate, Siberia plate and several intermediate massifs in the area, and the other con- cerns the folding and lifting of the Xingmeng Trough. Dis- agreements arise because of issues involving the tectonic- palaeogeographical environment of the Upper Permian deposits of the Linxi Formation. The Linxi Formation （Upper Permian） is generally considered to be either an exclusively continental deposit or separated into marine- terrigenous facies deposited during the Lower to Middle Linxi Period and continental deposits in the Upper Linxi Period. However, in this study, large numbers of bryozoan and sponge spicule fossils were discovered for this first time in the thick limestone layers and lenses of the upper part of the Linxi Formation found in the Guandi section of Linxi county in eastern Inner Mongolia. At the same time, abun- dant bryozoan fossils were also found in sedimentary tuff slices that were collected from the upper part of the Tao- huayingzi Formation from the Taohuayingzi section in Ar Horqin Banner, and abundant small connecting body crinoid stem fossils were found in the dark shale of the Yangjiagou Formation from the Yangjiagou section of Jiutai county, Jilin Province. These marine fossils provide the first evidence that the Xingmeng area was still a marine or mainly marine environment at the end of the late Permian. This not only provides conclusive evidence for the recognition of the above two major geological issues but also promotes chan- ges in the approach towards research, exploration and development of oil and gas, shale gas （oil）, and other mineral resources that are preserved in the late Permian layers of the Northeast-Xingmeng area.     

华北北缘大青山小井沟岩体年代学、地球化学和Hf同位素特征及其地质意义

为了加深对华北北缘晚古生代构造背景以及古亚洲洋闭合时限的认识, 对华北北缘大青山地区小井沟花岗岩开展了年代学、地球化学和同位素研究。分别利用LA-MC-ICP-MS, ICP-AES和ICP-MS等方法进行锆石U-Pb测年, 主、微量和稀土元素分析以及锆石Hf同位素测试。结果表明, 小井沟岩体侵位于二叠纪, 侵位年龄为275±1 Ma (MSWD=0.93)。该花岗岩具有高硅(SiO₂=70.72%~72.64%)、高钾(K₂O=4.19%~4.23%)的特点, A/CNK均约为1.1, 属于弱过铝质的高钾钙碱性系列, 稀土元素总量(ΣREE)为87.67~101.51 μg/g, 配分曲线呈右倾型, 具有微弱的Eu负异常, 富集大离子亲石元素(LILE, 如Rb, Ba, K, Sr等), 亏损高场强元素(HFSEs, 如Nb, Ta, Y, Yb, Lu等), 应该是由下地壳部分熔融形成。该花岗岩的锆石具有负的ε_Hf(t)值(-9.56~-5.00), 模式年龄(T_DM2)在1.91~1.61 Ga之间, 表明华北陆块古元古代的地壳岩石应该是其主要物源, 可能有幔源物质的参与。结合整个华北北缘二叠纪花岗岩的岩浆演变特征, 小井沟岩体应形成于由俯冲向碰撞-后碰撞转变的过渡时期, 古亚洲洋可能在晚二叠世之前已闭合。     

伊犁盆地二叠系烃源岩特征

综合运用有机岩石学、热解分析及机地球化学等方法,以地表剖面暗色泥岩的分析资料为主,结合部分井下暗色泥岩样品分析数据,研究了伊犁盆地二叠系烃源岩的有机质生烃特征,并分析了控制烃源岩生烃条件的影响因素。研究表明：中二叠统塔姆齐萨依组暗色泥岩为二叠系主要的烃源岩层系：有机质类型以Ⅱ2-Ⅲ型为主,部分层段有机质类型较好,可达到Ⅱ1型。认为二叠系烃源岩已不同程度进入成熟－高成熟阶段。     

新疆胜利和田探区南部下二叠统烃源岩的有机地化研究

以下二叠统克孜里奇曼组（P1k)海相碳酸盐岩为主要研究对象,对新疆胜利和田探区南部的石炭－二叠系海相烃源岩开展了系统研究。有机岩石学分析表明,该套烃源岩具有陆源和海相有机质双重输入的特点,有机质呈现偏腐殖的特征,干酪根以Ⅲ,Ⅱ型为主,与碳酸盐岩通常具有的较好有机质类型存在一定差别。有机地化分析也支持上述结论,并且指示出沉积环境并非严格的强还原环境。分析认为造成有机质类型较差的原因主要有3种,即陆源有机质输入、宏观藻类的贡献以及沉积环境充氧造成的有机质氧化。根据以上有机岩石学和有机地化分析的结果,结合碳酸盐岩孔隙度低,排烃较晚的特点,确定该套烃源岩以生成轻质烃类为主。塔西南地区广泛发育有石炭－二叠系海相碳酸盐岩沉积,该套气源岩对于区内天然气的勘探具有一定的石油地质意义。     

Late Permian magnetostratigraphy and its global correlation

A calibration among magnetic polarity sequence, biostratigraphy zonation and isotopic age reveals that the boundary between the Carboniferous-Permian reversed Polarity Superzone and Permian-Triassic Mixed Polarity Superzone occurs at the top of the Wordian Stage of the Guadalupian Series and is dated as 265 Ma. The Late Permian magnetic polarity sequence integrates four polarity zones, corresponding to the Upper Guadalupian Series, the Wuchiapingian Stage, and the Lower and the Upper Changhsingian Stage of the Lopingian Series. This reference magnetostratigraphy polarity sequence may serve as a useful guide to the chronostratigraphic correlation of Late Permian strata across major biogeographic and facies barriers.