渝南—黔北奥陶系五峰组的同生变形构造及其地质意义

重庆綦江奥陶系五峰组中—下部的黑色页岩中发育有一系列主要由阶梯状断层和其间的小型褶皱构成的同生变形构造(contemporaneous deformed structures),并可大致分为3个构造层段。沉积后—固结成岩前所形成的同生变形构造层之上为正常沉积的黑色页岩层。另外,在贵州桐梓五峰组距底部2.3m左右的黑色页岩中也发育有与綦江地区相似的、以小型褶皱为主的同生变形构造层,且此同生变形构造层上下为斑脱岩层。同生变形构造的发现,表明渝南—黔北地区奥陶纪晚期(五峰期)的沉积盆地为非平坦的古地貌,且曾发生过多期可能与火山运动相关的构造运动。     

云南大关志留系龙马溪组灰岩层显示的台缘相特征

上扬子区陆表海志留纪早期龙马溪组下部多为黑色笔石页岩,是全球海进期平缓海底缺氧状态的特有标志。滇东北大关黄葛溪剖面属埃隆阶下部Demirastrites triangularis带至Lituigraptus convolutus笔石带的龙马溪组页岩中夹含厚度约3m的薄层灰岩,其地理分布局限。对该灰岩的岩相特征分析显示,其中的蠕滑构造是碳酸钙沉积物在成岩固结前因海底坡度偏大产生的变形,粒度韵律层则属快速沉积单元,偶见风暴级强水流远源携带的小砾石。推测滇黔桂古陆西侧近岸区短暂时间段出现了小型浅水灰岩台地,大关黄葛溪剖面正处于小型台地向东延伸与斜坡交界的位置,这里的海底坡度较大,出现富氧带灰岩与缺氧环境黑色碎屑岩穿插的沉积。     

神农架及其周缘地区五峰-龙马溪组页岩微观孔隙结构特征及其含气性评价

近年来随着我国页岩气勘探领域从上扬子地区逐步扩展到中扬子地区,位于中扬子的宜昌、神农架地区由于广泛发育五峰-龙马溪组黑色页岩而受到了较多的关注。本次研究通过对比鄂西宜昌、神农架地区与川东焦石坝地区五峰-龙马溪组黑色页岩的地球化学特征、孔隙结构特征和构造保存条件等因素,综合评价宜昌、神农架地区五峰-龙马溪组富有机质页岩的含气性。结果表明,神农架背斜北翼八角庙剖面五峰-龙马溪组黑色页岩发育以微孔和介孔为主的有机质孔隙,与宜昌和焦石坝地区五峰-龙马溪组黑色页岩孔隙特征相似,具备良好的页岩气储集空间。宜昌、神农架地区与焦石坝地区的五峰-龙马溪组黑色页岩在厚度、热演化程度、矿物组成、页岩孔隙类型和分布特征上有很大的相似性,但在页岩的分布范围、有机质丰度及类型上均存在差异。另外,宜昌、神农架地区受宜昌上升运动等构造活动的影响,在古隆起中心部位的五峰-龙马溪组遭受严重剥蚀破坏,页岩气保存条件较差,仅在古隆起周缘地区还发育保存条件较好的富有机质页岩。综合认为位于黄陵隆起东缘的宜昌斜坡带是今后鄂西、渝东地区页岩气勘探开发的有利地区。     

扬子区西南缘奥陶纪末—志留纪初笔石生物地层对比及意义

利用扬子西南缘天全、汉源、甘洛、布拖、金阳、永善、绥江、大关地区五峰组—龙马溪组重点剖面露头点和钻井岩心资料,通过笔石生物地层划分,建立了五峰组—龙马溪组黑色页岩的等时地层格架。通过对比纵横向黑色页岩的TOC含量、沉积厚度、优质页岩厚度等数据变化,探讨笔石带的分布与沉积环境、优质页岩的关系。结果表明,各剖面和钻井中WF2—LM4笔石带优质页岩普遍发育。其中布拖、金阳靠近康滇古陆边缘的地区,LM5笔石带、LM6笔石带岩石地层明显增厚;永善—绥江云永地2井、新地2井、绥江B井等地区,笔石带分布和沉积环境相似,优质页岩沉积上界由LM4笔石带逐步上延至LM6笔石带。五峰组—龙马溪组优质页岩在靠近康滇古陆一侧沉积时限为WF2—LM4及以下笔石带,远离古陆一侧沉积时限呈逐渐变长的趋势。天全大井坪、汉源轿顶山一带WF2—LM5笔石带优质页岩发育,轿顶山地区岩石地层厚度明显减薄,天全大井坪地区明显增厚,受特殊环境影响可能仍具有良好的勘探潜力。研究成果对扬子西南缘页岩气沉积有利区优选提供了依据。     

川东多套滑脱层褶皱构造带形成物理模拟

川东地区发育典型的"侏罗山式"褶皱构造带,以北东走向的齐岳山断裂为界,南东侧为隔槽式褶皱,北西侧为隔挡式褶皱.中生代川东地区经历了自南东向北西的陆内递进变形,受多套滑脱层（基底拆离面、下寒武统页岩、志留系泥页岩和三叠系膏盐）的共同控制.但是,关于川东褶皱带的形成机制及其整体和分段形成时间仍存在较大争议.应用构造物理模拟方法,再现了川东"侏罗山式"褶皱带的形成过程,并分析了先存断裂及其倾角对川东褶皱构造变形的影响.模拟结果表明,川东褶皱带是齐岳山断裂、华蓥山断裂、志留系滑脱层和基底拆离面组成的阶梯状体系在构造挤压下发生断层相关褶皱作用的结果.基底拆离面（深度约16 km）控制隔槽式褶皱的发育,志留系页岩主要控制隔挡式褶皱的形成.中生代（165~75 Ma）川东地区的构造缩短率约为32%.齐岳山断裂是隔槽式褶皱向隔挡式褶皱过渡的重要枢纽,是先存高角度断裂浅部向北西迁移后的产物.华蓥山断裂的倾角控制着隔挡式褶皱的波长,当倾角较陡时（45°）更有利于发育典型的隔挡式褶皱.      

下扬子地区晚奥陶世凯迪期—早志留世鲁丹期岩相古地理及其油气地质意义

下扬子地区奥陶—志留纪之交岩相分异明显,发育了多种类型的岩石地层单位,其沉积岩的颜色、岩性、厚度、赋存化石组合等方面存在显著的差别。笔者通过对研究区内野外露头及钻井剖面的考察,总结前人研究成果,利用岩石学、古生物学、生态学及室内分析方法将其划分为滨岸相、孤立台地相、浅海陆棚相、陆棚坡折相、欠补偿盆地相和盆地浊积岩相6种沉积相类型。岩相古地理研究表明,晚奥陶世凯迪晚期,受加里东构造运动影响,华南板内碰撞挤压作用显著,"江南古陆"不断抬升和扩张,直接导致了旧的"台-坡-盆"格局的消失和新的古地理格局的形成,之前发育的自西北向东南方向水体变深的古地理格局彻底转变为北西、南西、南东三面被古陆包围,向东北方向水体加深的古地理格局。晚奥陶世赫南特期,由于南极冰盖凝聚导致的全球海平面下降和气候变冷,扬子地台海域变浅,致使海底盆地上升到最低含氧深度面之上处于充氧水层中,富氧环境代替了缺氧环境,岩相由五峰组黑色页岩转变为更浅水的观音桥层泥灰岩或新开岭层泥岩;江南沉积区长坞组—于潜组的复理石沉积组合转变为更浅水的的文昌组—堰口组近磨拉石沉积组合。早志留世鲁丹期,随着全球海平面重新上升,隆起面积继续扩大,构造围限作用加剧,黑色页岩重新出现。尤其是安徽南部的安庆—铜陵—巢湖一线,江苏中部的南京—句容一线五峰组—高家边组底部的黑色硅质页岩和炭质页岩,笔石带与中上扬子的五峰—龙马溪组具有很好的一致性,厚度均在40～60 m,TOC含量1.2%～4%,具很好的生烃潜力,应视为下一步烃源岩及页岩气勘探开发的重点研究区域。     

海相优质页岩的形成环境及发育模式——以中扬子地区秭归新滩剖面五峰—龙马溪组页岩为例

运用地球化学和岩石学方法,从古盐度、古气候、古生产力、海域封闭性以及氧化还原条件等方面,分析中扬子地区秭归新滩剖面上奥陶统五峰组—下志留统龙马溪组海相优质页岩的形成环境,并探讨了优质页岩发育的控制因素及模式。结果表明:中扬子地区五峰—龙马溪组优质页岩以硅质页岩为主,主要发育在五峰组至埃隆阶底部;优质页岩主要形成于温暖潮湿、低盐度—正常盐度、弱封闭—半封闭的缺氧环境中,并且具有较高的古生产力;海相优质页岩的发育是构造活动、海平面升降以及陆源—生物硅质供应等多因素综合作用的结果,而在埃隆期之后,随着扬子板块的持续向西北推进,海域面积不断萎缩,生物硅质供应降低,陆源碎屑供应迅速增加,优质页岩不再发育。最后,总结了海相优质页岩的发育模式。     

山东灵山岛滑塌体内部沉积及构造特征研究

青岛市灵山岛修船厂剖面下白垩统地层中发育良好的滑塌变形体。野外观察可见滑塌体岩性单元主要由厚层砂岩及砂页岩互层组成,其中厚层砂岩根据其沉积构造及成因机制可分为砂质碎屑流沉积及浊流沉积两类;砂页岩互层段砂岩层可见底模构造及粒序层理,为静水环境下远端浊流沉积。滑塌体内部构造主要可分为软褶皱变形、同生断层、透镜状砂质团块三种类型。其中,软褶皱变形根据岩性可分为砂岩软褶皱、砂页岩互层软褶皱及页岩软褶皱,随着变形强度增加,软褶皱枢纽逐渐平行于滑移方向,形成曲脊软褶皱或软鞘褶皱(soft sheath folds);同生断层出现在砂岩层中,根据力学性质分为正断层及逆断层,正断层为剪切拉伸所致,逆断层为软褶皱逆冲所致;透镜状砂质团块包括同沉积布丁构造和同沉积断块。根据滑塌体内部滑移面识别出三期滑塌,完整的滑塌体由底部拆离滑移面、下部厚层砂体、中部砂页岩互层及上部砂页岩互层未变形体组成,其组成特征及各部分接触关系反映了滑塌体中下部沿底部拆离滑移面发生滑塌变形,且于活动末期在相对静水条件下被上部砂页岩互层覆盖这一形成过程。根据滑塌体内部组成特征的有序性、相似性及滑塌体内部沉积构造特征,推测其触发机制可能为沉积物快速沉积所引发的重力滑塌成因。     

滇黔桂地区微细浸染型金矿控矿地质条件分析

滇黔桂地区微细浸染型金矿是80年代以来发现的产于碳酸盐岩、碎屑岩系中的重要金矿矿化类型。本文分析认为滇黔桂地区是晚二叠世后古地块裂开形成的构造三角形裂陷盆地,印支晚期由于扬子古陆、江南地块与越北地块的聚合作用,导致形成了复杂的褶皱断裂构造体系,划分为南盘江构造域、北盘江构造域与普安－安龙构造城;含矿建造为裂陷期形成的火山碎屑岩夹的热水沉积硅质岩与沉降期形成的碎屑岩系;控制矿床、矿田分布的是基底隆起构造、不同构造域叠加构造及紧密褶皱与断裂伴生的构造。     

南大巴前陆冲断带构造变形几何类型、分布特征及其成因分析

南大巴前陆冲断带位于秦岭造山带向四川盆地过渡的部位,是晚三叠世扬子-秦岭俯冲碰撞与中新生代以来陆内造山形成的。根据构造变形的几何学特点,自北东向南西发育紧靠城口断层的根带、坪坝断裂与鸡鸣寺断裂之间的中带、镇巴-鸡鸣寺断裂与铁溪-巫溪隐伏断裂之间的锋带。各带发育不同的构造变形:根带的冲断层系统以逆冲叠瓦构造为主控构造组合,同时发育构造三角带、冲起构造和双重构造等组合;中带的冲断褶皱系统以发育断层相关褶皱组合为主;锋带发育为滑脱褶皱系统,以类侏罗山式褶皱为主控构造,同时发育了箱状背斜、膝折构造、倒转背斜、平卧褶皱、紧闭背斜、同斜背斜、虚脱不协调背斜等滑脱褶皱。垂向上发育3套区域性滑脱层:震旦系泥页岩和寒武系泥页岩、志留系泥页岩、下三叠统膏盐岩;在南秦岭自北而南的推覆作用下,依次沿这3套滑脱层逐级抬升而向南滑脱,存在"推覆作用(叠层滑动)→冲断作用(切层滑动)→层滑作用(顺层滑动)"的滑脱变形序列,从而造就南大巴的多种构造变形类型及其有序分布特征。     

Radiolarians from Upper Jurassic (Middle Oxfordian and Upper Kimmeridgian) deposits of Yaroslavl oblast

The middle Oxfordian and late Kimmeridgian radiolarian assemblages from Upper Jurassic deposits of Yaroslavl oblast are studied for the first time. The middle Oxfordian assemblage is dominated by stauraxonic morphotypes of genera Paronaella and Pseudocrucella occurring in association with discoid forms. Nassellarian radiolarians are very rare in this assemblage of extremely low taxonomic diversity, which is lacking spheroidal morphotypes. The late Kimmeridgian assemblage is more diverse in morphological and taxonomic aspects. It includes spheroidal forms, those of the family Pantanelliidae Pessagno inclusive, and more frequent nassellarian species, but stauraxonic radiolarians are less abundant in its composition. This assemblage is comparable to a considerable extent with the Kimmeridgian radiolarians from Moscow oblast, being of the South Boreal type according to its composition.     

The Upper Miocene Injana (Upper Fars) Formation of Iraq: insights on provenance history

Petrographic, geochemical, and scanning electron microscope analyses of the sandstone and mudstone units of the Upper Miocene Injana Formation are presented. Furthermore, microprobe analysis for amphiboles, pyroxenes, garnet, and chromian spinels as common heavy mineral species present is done to support other results for better understanding of the provenance history of the Injana Formation. The sandstones of the Injana Formation consist of terrigenous carbonate lithic fragments as common type of sedimentary rock fragments in addition to chert, argillaceous, and rare sandstone fragments. They also include metamorphic and igneous lithic fragments, quartz, feldspars, and mica and generally, the sandstones are lithic arenites and immature. Scanning electron microscopic analysis for the heavy minerals shows that they have been affected by dissolution due to chemical etching and mechanical abrasion through several surface texture generated either in arid and semihumid environment or in diagenetic environment. Clay mineralogy of the mudstone units indicates the presence of illite, chlorite, kaolinite, palygorskite, and illite–smectite mixed layers. Bulk-rock and mineral phase geochemistry in addition to petrographic data suggest the derivation of the Injana Formation from a nearby sources with contribution from igneous, metamorphic, and sedimentary provenance mainly from the high lands in the northeastern parts of Iraq which comprise mainly the Zagros mountains and the older sedimentary formations.     

通量上边界与水头上边界方法的地下水流系统模拟对比

水头上边界方法（简称水头法,GHB）给定了潜水面形态和固化了排泄点,限制了不同地下水流系统模式的形成与转化。分别用数值法进行了通量上边界（简称通量法,FUB）与水头上边界的地下水流系统对比模拟。结果表明：嵌套式多级地下水流系统（Tóth典型模式）在运用水头法和通量法进行系统转化模拟时,得出的水流模式可能相似或完全不同;通量法在条件（盆地形态、入渗强度等）改变时潜水面能够自动形成,从而得出不同变化条件下的水流系统特征;水头法由于给定了潜水面和固化了排泄点,在改变盆地其他因素时,盆地补给（排泄）也发生同步改变,此时地下水流模式不是单因素变化的结果,因此在给定条件下不能得出完整的地下水流系统变化模式。基于通量法与水头法在地下水流系统模拟中的优势与不同,在进行盆地地下水流系统理论和实际研究时,应该综合2种方法的特点,结合实际资料条件进行方法的选取与应用。     

Calpionellid biostratigraphy of the Upper Tithonian–Upper Valanginian interval in Western Sicily (Italy)

A revision of the calpionellid bio-chronostratigraphy in Western Sicily (Italy) was carried out, in order to update the taxonomy of this group, through the identification of some genera (Borziella, Longicollaria, Chitinoidella, Dobeniella, Sturiella, Borzaiella and Praecalpionellites) and species (Remaniella catalanoi Pop, Remaniella duranddelgai Pop, Remaniella colomi Pop, Remaniella borzai Pop, Remaniella filipescui Pop) recorded for the first time in the area. The studied sections, belonging to the Trapanese and Saccense Domains (Western Sicily), include at the base the upper portion of the Rosso Ammonitico Unit (Upper Tithonian), followed by the Lattimusa Formation (Lower Cretaceous). The quantitative and biostratigraphic analysis of the calpionellid assemblages allowed us to identify 13 assemblages and to define some important bioevents for the Upper Tithonian–Valangianian interval. The recorded calpionellid bioevents allowed us to recognize Zone/Subzone schema, which have been correlated with the bio-chronostratigraphy previously proposed for the Western Tethys. Editorial handling: M. Chiari (Guest) & J.-P. Billon-Bruyat     

Upper mantle heterogeneities beneath Eastern Europe

P-wave travel-time residuals for seismograph stations in eastern Europe as reported by ISC for the years 1964–1977 were used for constructing a seismic image of upper mantle heterogeneities in the network region. For the depth range 0–100 km, dominant tectonic features like the Pannonian Basin and the Aegean Sea and western Turkey correlate well with pronounced velocity lows which a ppear to extenddown to a 300 km depth. The velocity anomaly patterns in the depth intervals 300–500 km and 500–600 km are broadly similar but quite different from those of shallower depths. The observed seismic heterogeneities are briefly discussed in terms of large-scale tectonic and geophysical (heat-flow) characteristics of eastern Europe.     

邯邢上二叠统上石盒子组和石千峰组岩石特征及界线划分

笔者在邢台、邯郸、峰峰等地的煤田地质勘探工作中,发现上二叠统上石盒子组与石千峰组碎屑岩中的碎屑物质成分有着明显的差异性。它反映了晚二叠世随着地质历史的发展,剥蚀区的基岩性质或物源区发生了更迭,这无疑为上二叠统石千峰组和上石盒子组的正确划分与对比提供了可靠的依据。      

Carbonate banks and slump beds in the Upper Cretaceous (Upper Turonian-Santonian) of Haute Normandie, France

Large scale sedimentary structures present in the Upper Turonian to Santonian chalks of Haute Normandie (northern France) represent the remains of a carbonate bank complex which formerly extended over an area of at least 1500 km². Cliff exposures along the Channel coast from St Valéry-en-Caux to Cauville and along the Seine from Sandouville to Lillebonne show sections of banks up to 50 m high and 1500 m across, their internal structures picked out by hardgrounds, nodular chalks and horizons of burrow flint. Associated with banks are slump sheets up to 20 m thick, slump scars, sedimentary breccias, injection phenomena and faults contemporaneous with sedimentation. Later diagenetic features include extensive dolomitization and silicification. These structures compare closely with the Waulsortian banks of the Palaeozoic, and bryozoan bioherms known from the Upper Cretaceous and Palaeocene of Denmark. Frame-building, sediment trapping and stabilizing organisms are absent, and bank development and stabilization was probably due to a plant covering, either algal or of marine angiosperms. Banks generated much of their own sediment, whilst a pelagic constituent (calcareous nannofossils and Foraminiferida) is also present. The distribution of the bank complex is related to a basement controlled swell area, whilst the life of the complex was limited to a relatively shallow water, regressive episode in the predominantly transgressive Upper Cretaceous history of the region. Les falaises littorales du Pays de Caux comprises entre Antifer et St Valèry-enCaux, et les affleurements de la basse vallée de la Seine permettent d'observer des formations du Turonien supérieur-Sénonien inférieur qui présentent des stratifications irrégulières soulignées par de nombreux hardgrounds, des horizons de craie noduleuse et des cordons de silex. Ces structures sont identifiées à des accumulations de calcilutite et calcarénite sous forme de bancs sous-marins dont la hauteur peut atteindre 50 m et qui couvrent une surface supérieure à 1500 km²; ils apparaissent au-dessus de hardgrounds subhorizontaux qui indiquent un haut-fond régional stable. Des glissements sous-marins sont associés à ces bancs et engendrent des niveaux avec des déformations souples atteignant 20 m d'épaisseur. Des brèches apparaissent localement et contiennent des blocs basculés de hardgrounds fragmentés lors du glissement; on y observe aussi de petites failles intrasédimentaires et des phénomènes d'injection. Aucun organisme constructeur ou capable de piéger et retenir le sédiment n'a été observé. La stabilisation de ces bancs serait due à une couverture végétale (algues ou angiospermes marines) dont on sait qu'elle peut disparâitre sans laisser de trace lors de la fossilisation. La croissance de ces bancs serait réalisée par un apport de sédiment comprenant une part de nourrissage autochtone comme cela existe pour les bancs récents en eau peu profonde, associée au dépôt d'une fraction pélagique.     

Hydrothermal Dolomite in the Upper Sinian (Upper Proterozoic) Dengying Formation,East Sichuan Basin,China

Hydrothermal Dolomite （HTD） is present in the Upper Sinian （Upper Proterozoic） Dengying Formation, east Sichuan Basin, China. The strata are comprised by primary dolomite. The HTD has various textures, including zebra dolomite, subhorizontal sheet-like cavities filled by saddle dolomite and breccias cemented by saddle dolomites as well occur as a fill of veins and fractures. Also co-occur MVT type lead-zinc ores in the study area. The δ13C and δ18O isotopes of HTD in the Upper Sinian Dengying Formation are lighter than those of the host rocks, while STSr/86Sr is higher. The apparent difference in carbon, oxygen and strontium isotopes, especially the large difference in S7Sr/S6Sr isotopes ratio indicate crystallization from hot basinal and/or hydrothermal fluids. Saddle dolomite was precipitated at temperatures of 270-320℃. The diagenetic parasequences of mineral assemblage deposited in the Dengying Formation are： （1） dolomite host rock →sphalerite-galena-barite-fluorite; （2） dolomite host rock →saddle dolomite →quartz; （3） dolomite host rock →saddle dolomite→bitumen; （4） dolomite host rock →saddle dolomite →barite. The mean chemical composition of the host dolomite matrix and HTD didn＇t change much during hydrothermal process. The fluids forming the HTDs in the Dengying Formation were mixtures of freshwater from the unconformity at the top of Sinian, fluids from diagenetic compaction and hydrocarbon generation ＆ expulsion from the Lower Cambrian Niutitang Formation mudstones or the Doushantuo Formation silty mudstones, and hydrothermal fluids from the basement. The hydrocarbon reservoirs associated with the HTD were mostly controlled by the basement faults and fractures and karsting processes at the unconformity separating Sinian and Cambrian strata. The hydrocarbon storage spaces of HTD included dissolved cavities and intercrystalline pores. Dissolution cavities are extensive at the top of Dengying Formation, up to about 46m below the unconformity between Sinian an