鄂西地区长阳组的时代问题

对长阳组命名剖面的重新观察和研究表明,原认定的长阳组层位不存在误认的问题.来自长阳组命名剖面和相邻剖面长阳组的两件牙形石样品的分析结果显示:长阳组的牙形石化石组合以Siphonodella levis大量发育为特征,兼有少量的Polygnathus inormatus、P.cf.symmetricus、Bispatho...     

川西坳陷彭州地区雷口坡组天然裂缝发育特征与形成期次

利用野外露头、岩心、薄片及地球化学等资料对四川盆地川西坳陷彭州地区雷口坡组天然裂缝发育特征及形成期次开展了研究.研究区宏观裂缝按成因可划分构造裂缝和和非构造裂缝,构造裂缝包括张性裂缝、剪性裂缝和破碎状裂缝,非构造裂缝主要为风化网状裂缝.宏观裂缝以构造裂缝为主,主要为剪性裂缝和张性裂缝,其中的垂直裂缝、高角度裂缝的发育密...     

论浙江平水群的划分和地质时代

依据实测的浙江省浦江县蒙山剖面,建立二个地层单位层型：蒙山组和陈塘坞组,二组归并为平水群。平水群为岩石地层清理前所用的地层名称,本研究予以恢复并修订了它的含义。平水群下部为蒙山组细碧角斑岩建造,上部为陈塘坞组海相砂泥岩建造,与上覆地层双溪坞群为整合关系;它代表浙江省西北部最古老的基底。通过对层型剖面微古植物化石和同位素年龄的研究对比,提出平水群地质时代归属中-新元古代。      

Largest Toothed Pterosaur Skull from the Early Cretaceous Yixian Formation of Western Liaoning,China, with Comments on the Family Boreopteridae

A new pterosaur Moganopterus zhuiana gen. et sp. nov. is erected based on a complete skull with lower jaws and anterior cervical vertebrae. It is characterized by much elongated upper and lower jaws with at least 62 total, long, curved teeth with sharp tips, a well developed parietal crest extending posterodorsally, forming an angle of 15 degrees with the ventral margin of the skull, the ratio of length to width of cervical vertebrae greater than 5:1. The skull length is 750 mm, and it is the largest toothed pterosaur found so far in the world. Based on this new pterosaur, the Boreopteridae can be divided into two subgroups: Boreopterinae sub-fam. nov. and Moganopterinae sub-fam. nov., which is also confirmed by the phylogenetic analysis.     

厚油层内部夹层特征及在剩余油挖潜中的应用

以岩芯、测井、分析化验和生产动态等资料为基础,通过静态和动态研究相结合的方法,对东濮凹陷古近系沙河街组厚油层内部夹层类型、成因和展布特征,对剩余油的控制作用及其在挖潜中的应用进行了研究。结果表明：东濮凹陷厚油层的夹层类型主要有泥质、物性和钙质夹层三类,以泥质夹层为主,前两者属沉积成因,而钙质类层主要属成岩成因。从厚油层内部夹层的空间分布特征来看,可将其分为层状连续分布夹层、片状不稳定分布夹层和不规则冲刷一充填夹层3种。统计结果表明：横向延展非常稳定且井间对比性较强的夹层数量约占30％,而横向延展稳定性较差且连片程度不高,具空间随机性分布特征的夹层数量约占70％。夹层空间分布特征与注采配置方式共同控制了厚油层内部的不同剩余油分布模式,对夹层的深入研究有效提高了对厚油层内部剩余油的认识精度。从不同空间分布夹层所控制的剩余油分布特征出发,采用水平井、井网整体调整、补孔等方法和措施可获得较好的挖潜效果。     

东昆仑山香日德南部白沙河岩组的岩石组合特征和形成年代的锆石Pb-Pb定年启示

柴达木盆地南缘香日德南部金水口岩群白沙河岩组的岩石组合自下而上为长英质片麻岩-钙质片麻岩 斜长角闪岩-大理岩组合.白沙河岩组和侵入该岩组的变质花岗岩的锆石逐层蒸发Pb-Pb定年结果表明:白沙河岩组的陆源碎屑来自一个具有2.1～1.9 Ga岩浆变质热事件的陆源区,当考虑现有的年龄资料时,该岩组的形成年龄可进一步约束在1.6～1.0 Ga间;柴南缘的晋宁期深成侵入活动可能推前到中元古代末.     

超压对川东南地区五峰组-龙马溪组页岩储层影响分析

四川盆地东南部保存条件较好的五峰组-龙马溪组页岩普遍存在超压,且在其他地质条件相同的情况下,超压页岩储层相对于常压、低压储层具有更高的孔隙度.研究表明,富有机质页岩在适中的热演化过程中,由于烃类的大量生成,形成较多有机质孔隙,增加了页岩储层储集空间;另一方面,烃类大量生成造成的超压对页岩储层储集空间保存具有至关重要的作用.川东南五峰组-龙马溪组优质页岩储层孔隙以有机质孔、黏土矿物孔等塑性孔为主,且缺少刚性矿物颗粒支撑,易被上覆地层有效应力压实.但超压的存在对于页岩储层具有保护作用,抵消了上覆地层有效应力对页岩储层的机械压实,从而使已形成的页岩孔隙保存下来,使页岩储集空间得以保留.研究超压对页岩储层孔隙度影响机制以及超压页岩储层发育模式对于四川盆地五峰组-龙马溪组页岩气勘探、开发具有重要意义.     

萨拉乌苏河流域萨拉乌苏组砂丘砂沉积特征

The Salawusu Formation of Milanggouwan section in Salawusu River Valley includes 7 layers of paleo-mobile dune sands, and 4 layers of paleo-fixed and semi-fixed dune sands. Their structures have been observed and their grain size, surface textural features and several main chemical elements have been analyzed. The results showed that： 1） Some of the aeolian structural characteristics of these dune sands are similar to that of the recent dune sands. 2） They are also similar to the recent dune sands in grain size components, and parameters of Mz,σ, Sk and Kg, as well as in several main chemical components. 3） The scattergrams of Mz-σ and SiO2-Al2O3＋TOFE and the probability curves of grain size showed that these paleo-dune sands are different from paleosols and fluvio-lacustrine facies, but are consistency with recent dune sands. 4） Quartz sands have well roundness and surface textural features such as dish-shaped pits, crescent-shaped pits, pockmarked pits, upturned cleavage plates, siliceous precipitates and siliceous crevasses, indicating that they had been carried for a long time by the wind. As the 11 layers of paleo-dune sands possess the aeolian characteristics in structure, grain size, surface textural features and chemical elements, the origin of their formation should be attributed to eolation.     

扬子板块北缘下志留统龙马溪组重晶石结核特征及其成因机制分析

在扬子板块北缘城口明中剖面及巫溪徐家坝剖面下志留统龙马溪组底部的硅质岩、泥岩中发现椭球状重晶石结核。其矿物组成主要为重晶石颗粒与作为"基质"的黄铁矿、粘土矿物和石英。通过重晶石岩石学、矿物学及锶同位素分析表明,重晶石结核形成于早期成岩阶段松软沉积物的孔隙水中。上升洋流带来丰富的营养及富钡物质,表层海水的高初始生产力促使生物繁盛,海水中的钡通过生物作用富集形成生物钡,生物钡(bio-barite)在埋藏过程中的硫酸盐耗竭区(sulfate depleted zones)通过硫酸盐细菌作用(BSR)溶解被激活提供了钡的来源。围岩岩性(黑色泥岩和硅质泥岩)表明重晶石结核形成于缺氧的环境中。上述研究对深入理解早志留世时期扬子板块北缘古海洋环境有一定的启示作用。