Foraminiferal Biostratigraphy of the Mobarak Formation (Lower Carboniferous) in Kiyasar Area,SE Sari,Northern Iran

The Mobarak Formation is near the town of Kiyasar in the south-east of Sari city, northern Iran. This formation conformably overlies the Geirud Formation (Upper Devonian). The lower part of the Mobarak Formation consisting of shales and thin- to medium-bedded limestone toward the top of these sequences changes into alternations of dark limestone and interbedded gray to black shales. Weathered yellow thick-bedded shales are observed at the top of the section. This formation is covered unconformably by sandstones attributed to the Dorud Formation (Lower Permian). The thickness of the formation in this region is 250 m. Four rock units have been recognized in this section. Foraminiferal biostratigraphy shows that the age of the Mobarak Formation in the Kiaysar region ranges from Lower Tournaisian to Early Middle Visean. The foraminifer Zones FAZ1 and FAZ2 are correlated with the Lower Tournaisian and Upper Tournaisian, whereas Zones FAZ3 and FAZ4 correlate with the Visean. Affinities exist between specimens recorded in the Kiyasar section with species known from other regions in eastern and Central Alborz, but there are important differences in their appearance.     

苏北盆地高邮凹陷联盟庄地区戴南组物源及沉积相研究

综合运用碎屑岩类分析法、重矿物法对苏北盆地高邮凹陷联盟庄地区戴南组的物源方向进行了分析。结果表明,戴南组物源具有不稳定性,早、中期物源均来自柘垛低凸起,物源方向由沿东北方向沉积演变为沿南北方向沉积;晚期物源来自西北部的菱塘桥低凸起。联盟庄地区戴南组沉积物为再旋回沉积物,母岩区构造背景为活动大陆边缘,其源岩主要为花岗岩和中基性火成岩。根据岩心、电测曲线、录井以及分析测试资料,对联盟庄地区戴南组的沉积相平面分布进行了研究,三角洲的展布受河湖作用及物源供应的影响,早、中、晚期分别呈朵状、朵叶状和伸长状。     

川南观音场-瓦市地区须家河组六段储层特征及其控制因素

通过对4条野外剖面、40口并岩心样品及84张薄片的观察和测井等资料的分析,对川南观音场一瓦市地区须六段的岩石学特征、孔隙类型、孔隙结构及孔渗特征等进行了深入研究。结果表明：川南地区须六段岩性主要为中-细粒长石岩屑砂岩和岩屑石英砂岩,孔隙度在6％～10％之间,平均孔隙度为7．3％。渗透率为0．03×10^-3μm^2～0．9×1010^-3μm^2平均渗透率为0．177×1010^-3μm^2储层属于典型的低孔低渗储层,储集空间主要为粒间孔和粒内溶孔。在平面上,储层物性受沉积相带的控制;在垂向上,随深度的增加,压实作用和胶结作用使物性急剧变差。绿泥石的环边胶结作用、长石的溶蚀作用对储层物性起建设性作用,构造作用极大地改善了储层的物性。     

Geology of the Hida Gaien Belt in the upper Kuzuryu‐gawa River Area in Ono City,Fukui Prefecture,Central Japan

Geological, paleontological, and geochronological studies of the Hida Gaien Belt were carried out in the upper Kuzuryu‐gawa River area, northern central Japan. The Hida Gaien Belt lies between the Hida and Mino belts of Southwest Japan and is one of the most complex geologic belts in Japan. The geology of the following units in the study area, mostly bounded by longitudinal, high‐angle faults, was particularly reexamined and described: the Ise metamorphic rocks, the Fujikuradani, Tomedoro, Oguradani, Motodo, Ootani, and Konogidani Formations, and the Tetori Group. Among them, the Tomedoro and Konogidani Formations are both composed mainly of greenstone, and were conventionally coupled together as ‘the Tomedoro schalstein member’ or ‘the Konogidani Formation’. However, the conformable relationship between the Tomedoro Formation and overlying Middle Permian Oguradani Formation, and the K–Ar and ⁴⁰Ar–³⁹Ar ages of 75–69 Ma (Late Cretaceous) from the basalt lava of the Konogidani Formation reveal that they are separate formations with different ages. The Oguradani Formation, consisting of limestone, shale, and sandstone with Middle Permian Boreal‐Tethyan mixed brachiopod fauna, is correlated with the Moribu Formation in the Takayama area of the Hida Gaien Belt, and with the Middle Formation of the Maizuru Group in the Maizuru Belt. The Tomedoro Formation below the Oguradani Formation, in turn, is correlated with the Lower Formation of the Maizuru Belt. The new Late Cretaceous age data from the Konogidani Formation and presence of latest Cretaceous, post‐tectonic volcanic rocks in the study area finally indicate that the fault‐bound structure of the Hida Gaien Belt between the Hida and Mino belts was formed in a very short period in Late Cretaceous age.     

鄂尔多斯盆地上三叠统延长组长6油层组储集层成岩作用及其影响因素

鄂尔多斯盆地延长组长6油层组储集层是受沉积作用和成岩作用共同控制的典型低孔低渗储集层.长6油层组储集层主要为长石砂岩、岩屑长石砂岩和长石岩屑砂岩.盆地北部砂体具有长石含量高和石英含量低的特点,西南地区具有长石含量低、石英含量高和杂基含量高的特点.储集空间以剩余粒间孔和次生溶蚀孔为主.主要成岩作用类型有压实作用、胶结作用...     

蜀南地区二叠系茅口组古岩溶地区水系分布及岩溶地貌单元特征*

蜀南地区茅口组为一套沉积稳定的巨厚层生物碎屑灰岩,基质致密性脆。中二叠世末的东吴运动使蜀南地区茅口组顶部发育古风化壳岩溶,古岩溶地区水系控制着古岩溶的发育和演化。在研究古地貌恢复方法的基础上,分析研究区地层特征和区域构造背景,采用印模法进行古地貌恢复,进而研究了古岩溶地区的水系发育特征。在此基础上,结合风化壳表面侵蚀溶蚀特征、沉积物性质、地貌组合形态、钻井和地震资料,把研究区划分为岩溶台地、岩溶陡坡、岩溶缓坡及岩溶盆地4种二级地貌单元和溶丘洼地、岩溶槽谷、峰林平原等10种三级地貌单元,进一步分析了各种地貌单元的岩溶特征,为下一步的储集层预测提供了有利的目标。     

渤海湾盆地黄骅坳陷孔南地区古近系孔店组二段物源分析*

根据重力异常资料、地震资料,综合运用重矿物法、碎屑岩类分析法并结合砂体展布特征,基本明确了黄骅坳陷孔南地区孔店组二段的物源区位置及来源方向。区域布格重力异常场从宏观上勾绘出了孔南地区地势的起伏状况,对物源分析具有重要参考意义。在研究区湖盆周缘都发育砂体,在各物源口的砂体展布规律在平面上表现为呈扇形展布的特征,宏观上指示了物源的涉及范围。盆外下切沟槽能大致确定研究区周缘各物源口位置,前积反射结构也能指示出存在物源供给的地区。重矿物以锆石、电气石、金红石、石榴石、磁铁矿为主,不同的物源区具有不同的重矿组合特征,其变化规律指示了碎屑物质的搬运方向和搬运途径。碎屑岩组分以长石为主,其次为石英,岩屑含量较低,主要为岩浆岩岩屑,岩屑类型指示了物源区母岩类型主要为岩浆岩。该区孔店组二段沉积时期在东南、西南、西北、东北4个方向上都存在物源,进一步可识别出乌马营、叶三拔、舍女寺等10个子物源,它们共同控制了孔南地区孔店组二段沉积时期砂体的形成和分布,形成多物源环湖盆分布的特征。     

冀西北尚义上侏罗统—下白垩统后城组恐龙足迹新发现及生物古地理意义*

简要报道了新近首次在冀西北张家口尚义地区发现的恐龙足迹。野外地质调查发现,恐龙足迹赋存于尚义晚中生代盆地侏罗系—白垩系后城组顶部。恐龙行迹呈近东西向展布,由数十个足迹构成。初步研究表明,造迹者分别属于兽脚类和蜥脚类恐龙,由西向东行进。足迹中包括兽脚类足迹70余个,组成数个行迹;蜥脚类足迹15个,构成1列行迹。蜥脚类足迹特征显示其可能属于游泳状的行迹。华北北部土城子组/后城组发育于燕辽生物群—热河生物群更替演化时期（晚侏罗世—早白垩世早期）,以往在该时期沉积物中罕见脊椎动物骨骼化石。近年来华北北部土城子组/后城组中频繁发现的恐龙足迹表明,燕辽生物群—热河生物群更替演化时期发育着以恐龙为代表的脊椎动物群。该发现将有助于进一步了解土城子组/后城组沉积时期恐龙属种的多样性及其生物古地理环境。晚侏罗世—早白垩世早期沉积古地理和古生态环境及其与恐龙动物群发育的研究有助于揭示陆地生物群更替演化和环境的关系。     

西藏尼玛北部新生代盆地沉积记录及控盆机理

通过野外地质调查和地层对比,将尼玛北部盆地新生代陆相地层定为牛堡组。根据岩石组合和沉积特征分析,尼玛北部盆地牛堡组可划分为扇三角洲相、湖泊相和冲积扇相。扇三角洲相可进一步划分为扇三角洲前缘和前扇三角洲2种亚相;湖泊相可划分为半深湖—深湖和滨湖—浅湖2种亚相。盆地的演化特征可分为盆地形成初始期、盆地扩张期和盆地萎缩期,3期的演化可分别对应牛堡组的一段、二段和三段。尼玛北盆地发育的各个阶段都跟古气候变化和构造活动有很大的联系,两者共同影响着盆地发育的各个阶段。结合前人的研究资料,认为尼玛盆地的发育时代为早白垩世末期—晚白垩世初。根据盆地边缘相与半深湖—深湖沉积相伴生、牛堡组底部发现火山岩夹层等沉积特征,可以推断尼玛盆地是一个具有走滑拉张性质的盆地。     

宁夏香山含煤区找煤方向及前景探析

宁夏香山含煤区掩盖面积大,勘查程度低,空白区多。通过对已有地质资料分析,线驮石煤矿区边界断层为倾向北东的正断层,在东部土坡组露头附近有一倾向南西的正断层,两断层形成地堑使区内的含煤地层得以保存。根据矿区边界断层以西勘查资料推测,断层以东至土坡组露头区域太原组发育较稳定的中厚煤层及部分不稳定的厚煤层,煤种为无烟煤,全区可采煤层预测资源量约3．8亿t,此外在深井预测区以西大范围掩盖区也可能赋存可观的煤炭资源,如果上述两区资源量得以证实,将会改变对香山含煤区煤炭资源的评价。