鄂尔多斯盆地西缘横山堡地区构造特征与油气勘探目标优选

鄂尔多斯盆地西缘北区横山堡地区是重要的油气接替区域。本文利用构造解析、地震勘探等技术方法,对研究区构造特征与油气勘探目标进行了研究。结果表明,晚侏罗纪末期,研究区为银川复背斜东翼,喜山期构造调整后转为前缘反冲带,由一系列西冲东倾逆冲断层与断背斜组成;该区可分为西部逆冲断褶带、中部逆冲断阶带和东部过渡构造带3个构造单元。断层可分为4级;以燕山期近南北—北北东向逆断层为主,其次为喜山期近东西向走滑断层,并错断了燕山期逆断层。构造样式为一系列东倾单向叠瓦状冲断组合,由近南北向逆断层及加持于其中的断块组成,断块往往为一些小型断背斜,其轴迹走向以近南北—北北东向为主。地质结构为深层滑脱型单向东倾冲断构造。根据上述研究,在沙亥庙断裂上盘断背斜构造高部位优选出一个钻探目标。     

鄂尔多斯盆地西缘中段构造特征与油气勘探前景

鄂尔多斯盆地西缘中段是西缘构造带的重要组成部分,关于该区的地下构造模式由于受地下构造复杂与地震资料品质差的影响长期以来缺乏清晰的认识。通过地表地质、大量地震资料的综合研究,纵向上以下古生界类复理石浊积岩系、上古生界煤系区域性滑脱层为界,将该区划分为上部的逆冲推覆构造系统和下部的原地系统。前者断裂、褶皱发育,由6个逆冲席组成,横向分带性特征明显,自西向东划分为逆冲推覆构造主体、前缘过渡带、前缘带三个带;后者构造变形较弱,总体为西倾单斜,局部地区发育完整背斜圈闭。前缘过渡带、前缘带及原地系统勘探目的层众多,油气成藏地质条件好,勘探前景较好;逆冲推覆构造主体目的层已裸露,油气生成与保存条件较差,勘探潜力欠佳。     

鄂尔多斯盆地西缘石沟驿地区晚三叠世沉积构造环境及其地质意义

对鄂尔多斯盆地西缘晚三叠世大地构造环境和区域应力场与石沟驿地区上三叠统沉积速率、碎屑组分和盆地充填样式等构造环境判别的综合分析,认为晚三叠世石沟驿地区为逆冲挤压构造环境,冲断带挤压挠曲作用形成前陆前渊拗陷,物源区为再旋回活动的褶皱冲断带.与典型前陆盆地相比,位于冲断带前缘的鄂尔多斯盆地为具石沟驿等前渊拗陷的类前陆盆地.晚三叠世石沟驿地区逆冲挤压和六盘山地区整体隆升的构造背景揭示,牛首山一罗山一带的西缘逆冲带构成晚三叠世鄂尔多斯原型盆地的西南部边界,石沟驿地区上三叠统是盆地延长组边缘相沉积.上述认识有助于扩大鄂尔多斯西缘中生界和古生界的油气勘探远景.     

天山南北前陆冲断带构造滑脱层分布差异及对圈闭样式的控制作用

天山南北前陆冲断带具有较强的差异变形特征,滑脱层的差异对前陆冲断带变形特征及圈闭样式的影响较大,对于天山南北油气勘探具有重要意义。以地震资料解释为基础,通过断距测量、缩短量统计及平衡剖面复原等手段,对天山南北前陆冲断带构造变形差异进行研究,取得如下认识:(1)天山南北前陆冲断带滑脱层性质不同,库车前陆冲断带以古近系膏盐岩为滑脱层,分层变形特征显著;准噶尔盆地南缘前陆冲断带深层断层多穿过滑脱层,分层性差;(2)天山南北前陆冲断带新生代构造变形差异明显,库车前陆冲断带在该时期的平均缩短率为12.1%,准噶尔盆地南缘前陆冲断带的平均缩短率为9.93%,库车前陆冲断带的新生代变形强度比准噶尔盆地南缘前陆冲断带更强;(3)受滑脱层差异的影响,库车前陆冲断带滑脱层上下平均断距总体大于准噶尔盆地南缘前陆冲断带,且库车前陆冲断带的缩短量呈现“单段多峰”复杂的变化趋势,这是准噶尔盆地南缘前陆冲断带没有的特点,表明库车前陆冲断带滑脱层塑性和分层能力比准噶尔盆地南缘前陆冲断带强;(4)基于天山南北前陆冲断带断层活动和滑脱层差异的影响,准噶尔盆地南缘前陆冲断带以岩性—构造的复合圈闭为主,而库车前陆冲断带以盐下大型构造圈闭为主,岩性—构造圈闭为辅。准噶尔盆地南缘前陆冲断带深层和库车前陆冲断带的侏罗系—三叠系煤层、泥岩层等滑脱层控制的岩性—构造圈闭是未来油气勘探的有利目标。     

叠合盆地差异构造变形与油气聚集

文中探讨叠合盆地差异构造变形特征及其对油气聚集的控制作用。叠合盆地差异构造变形受控于多期构造演化导致的多期构造应力场转换、多种变形介质变化以及多方位边界条件的变化,主要表现为:(1)受关键构造变革期应力场转换制约的分期差异构造变形,早期一般受区域伸展作用形成垒 堑构造,中期由于板块聚敛活动形成冲断滑脱和潜山 披覆构造,晚期在叠置的前陆盆地形成褶皱 冲断带;(2)受大型主断裂带控制的分带差异构造变形,这些大型主断裂带一般与先存基底断裂或基底软弱带有关,不同构造带的变形强度呈有规律变化;(3)受多层次滑脱带控制的分层差异构造变形,深层次滑脱构造变形主要表现为与盆山耦合有关的滑脱拆离变形,中层次滑脱构造表现为基底层系的滑脱拆离,浅层次滑脱构造表现为与盐膏岩或泥页岩有关的塑性构造变形;(4)受构造转换带控制的分段差异构造变形,区域性转换带本身常成为重要的横向构造带,不同构造段之间变形样式和运动学过程具有较大差别,局部构造转换带往往形成有利的油气圈闭。差异构造变形与烃源岩发育、油气成藏期、圈闭形成演化、油气藏形成和分布及油气保存条件密切相关。     

塔西南坳陷甫沙构造带正反转构造及其石油地质意义

塔西南坳陷甫沙构造带褶皱冲断强烈,古近系膏泥岩下层构造变形复杂,具有正反转构造变形特征。侏罗纪—白垩纪区域伸展环境发育大量正断层,后期在喜马拉雅运动中受挤压反转。南部发育高角度基底卷入正反转断层,中部发育叠瓦式逆冲断层,北部边缘变形微弱。相应地将甫沙构造带划分为反转断隆背斜带、楔状叠瓦构造带和逆冲前缘构造带;反转程度南强北弱、西强东弱。对区域构造变形环境的分析表明,西昆仑山隆升引发水平挤压叠加垂直向上的剪切作用,使先存高角度正断层容易被迁就利用进而发生正反转。对正反转相关构造圈闭评价认为:反转断隆背斜带发育的圈闭规模大,幅度低,埋藏浅,落实程度高,但上覆膏泥岩层薄,被断层破坏强烈,油气散失严重;楔状叠瓦构造带发育的圈闭规模小,幅度大,埋藏深,落实程度低,上覆膏泥岩层厚,有利于油气保存;逆冲前缘构造带发育低幅度隆起和地层岩性圈闭。     

南大巴山前陆冲断带构造样式及变形机制分析

大巴山构造带位于秦岭造山带和四川盆地的过渡部位,形成于印支-燕山期,定型于喜山期。按照构造变形样式及其组合特征,从北东向南西可依次划分为北大巴山逆冲推覆构造带、南大巴山前陆褶皱-冲断带(又包括叠瓦断层带、断层-褶皱带和滑脱褶皱带等3个亚带)和四川盆地东北部低缓构造区等3个构造带(区)。南大巴山冲断带地表构造以类侏罗山式褶皱为显著特征,主要发育叠瓦断层系、断层相关褶皱、被动顶板双重构造、反冲断层系和冲起构造等变形样式。北东-南西向挤压应力和滑脱层是控制南大巴山及其前缘构造变形的主要因素,结合区域地质研究成果,建立了南大巴山及其前缘地区依次从震旦系-下寒武统-志留系-中下三叠统逐渐抬高的多层次滑脱前展模式。     

尼日尔三角洲新生代褶皱作用及相关的油气圈闭

尼日尔三角洲是世界上重要的含油气区,褶皱构造在其油气藏形成中起着重要作用。本文根据尼日尔三角洲的石油 勘探资料,分析了褶皱的成因类型及不同类型褶皱的时序关系。尼日尔三角洲从陆上到海上可以划分为伸展带、过渡带和 挤压带等三个构造带,它们组成一个完整的重力滑动构造体系。伸展带以逆牵引滚动背斜为特征,以背斜型圈闭为主,断 块圈闭和岩性- 地层圈闭为辅;过渡带为泥底辟相关的披覆褶皱,以背斜型圈闭为主,伴生泥底辟肩部和之间的砂岩尖灭 圈闭;前缘挤压带发育逆冲断层相关褶皱,发育背斜和断背斜圈闭,背斜肩部和背斜之间发育砂岩尖灭圈闭。褶皱时间分 别始于始新世、中新世以及中中新世-上新世。褶皱作用引起的地层剖面的缩短平衡了伸展作用引起的剖面的伸长。尼日 尔三角洲与褶皱相关的圈闭,包括背斜、砂岩透镜体等富集了尼日尔三角洲绝大部分的油气。     

中国中西部褶皱冲断带构造变形机制与结构模型

基于复杂构造解析和实验模拟研究,揭示了中西部前陆褶皱冲断构造带主要表现为受侧向挤压形成的滑脱冲断构造变形过程和结构样式;明确了单层滑脱挤压冲断构造变形存在临界增生和非临界增生两种变形机制,发育脆性拆离型、塑性滑移型和黏性流动型3种作用类型,并受滑脱层强度、地层厚度、底部边界和外动力过程等4种主要因素影响。复杂冲断构造带基本上表现为受多层单滑脱作用控制形成的垂向叠置组合结构,本文提出了复杂滑脱冲断变形结构的可分解性以及受不同性质的滑脱层组合控制形成特征结构模式,并揭示了前陆冲断带前缘多滑脱构造变形结构中由浅层向深层逐渐发育的变形时序;建立了中西部再生前陆冲断带结构模型、构造单元以及基本构造类型;并基于前陆盆地多阶段构造演化过程以及晚期的隆升剥蚀-沉降沉积过程,提出了中西部两种类型冲断带的控油气作用及其勘探领域。     

鄂尔多斯盆地西缘马家滩地区冲断带断裂特征及其控藏模式

马家滩地区构造格架受基底断裂控制,具有东西分带、南北分块的特征;发育北部花状断裂系统、中部反转—冲断断裂系统和西部叠瓦—逆冲断裂系统3大断裂系统;形成挤压走滑型和反转冲断型(或逆掩推覆型)两类11种断裂组合样式,存在拉张—压扭、长期拉张—晚期挤压反转等8种断裂活动模式;油气藏受断裂控制而沿断裂展布,受断裂系统控制,发育断裂一输导层运移体系输导一正花状构造圈闭聚集—源外油气运聚成藏;断裂一输导层运移体系输导—断裂反转构造圈闭聚集—源内(古生界)源外(中生界)油气运聚成藏;断层—输导层运移体系输导—逆掩断层背斜(断鼻)构造聚集—源内(古生界)源外(中生界)油气藏成藏模式3种类型的断裂控藏模式。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

NONMETALS DEPOSITS

正20141520 Bo Ying(Key Laboratory of Metallogeny and Mineral Assessment,MLR,Beijing 100037,China);Liu Chenglin Saline Spring Hydrochemical Characteristics and Indicators for Potassium Exploration in Southwestern and Northern Tarim Basin,Xinjiang(Acta Geoscientica Sinica,ISSN1006-3021,CN11-3474/P,34(5),2013,p.594-602,5 illus.,3 tables,28 refs.)     

MATHEMATICAL GEOLOGY

正20141243Chen Ge(Hangzhou Research Institute of Petroleum Geology,PetroChina,Hangzhou 310023,China);Si Chunsong Study on Sedimentary Numerical Simulation Method of Fan Delta Sand Body(Journal of Geology,     

PROSPECTING EXPLORATION

正20142599Chen Sanming(Guangxi Key Laboratory of Concealed Deposits Exploration,Guilin University of Technology,Guilin541004,China);He Yuzhou Block Model and Reserves Estimation of Panzhihua Iron Deposit Based on 3D Geological Modeling(Journal of Guilin University of Technology,ISSN1674-9057,CN45-1375/N,33(4),2013,p.610-615,9illus.,1table,15refs.)     

STRUCTURAL GEOLOGY

正20140594 Bai Daoyuan(Hunan Institute of Geology Survey,Changsha 410016,China);Zhong Xiang Faults in the Jingzhou Basin and Their Tectonic Settings(Geotectonica et Metallogenia,ISSN1001-1552,CN44-1595/P,37(2),2013,p.173-183,6illus.,59refs.)Key words:basin evolution,tectonic setting,South China In the Upper Paleozoic and Jurassic se-     

STRUCTURAL GEOLOGY

正20141912Cao Hui(State Key Laboratory for Continental Tectonics and Dynamics,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China)Gravitational Collapse and Folding during Orogenesis:A Comparative Study of FIA Trends and Fold Axial Plane Traces(Geology in China,ISSN1000-3657,CN11-1167/P,40(6),2013,p.1818-1828,9illus.,35refs.,with