中小型陆相红色盆地区调方法探讨

从中小型陆相红色盆地沉积的基本组成和结构特征入手，重点就区调填图中存在的问题及区调方法，内容等进行分析与探讨，红层区冲积扇体是一种特殊类型的沉积地质体，为揭示期时空分布规律，提出被某些特征面所分隔，同期洪积事件形成的各种冲积扇体组成与“组”相当的基本填图单位；在扇体内进一步划分岩性段与扇根，扇中，扇缘岩相带。     

民和盆地上侏罗统湿型冲积扇沉积

本文通过岩相特征、粘土矿物分布、早期成岩矿物组合、微量元素等特征的综合分析，认为民和盆地上侏罗统下部为一较典型的湿型冲积扇沉积。冲积扇扇中发育河道冲刷充填和漫流沉积，而泥石流不发育。沉积层序与现代湿型冲积扇可对比。扇体中粘土岩及早期成岩矿物组合中富含高岭石，应与扇体发育时的潮湿气候和弱酸性流体的较强的淋滤有关。由粘土岩中微量元素因子分析进一步表明，该地层中富硼、钒的特征与相邻非扇相地层明显不同     

西北地区中新生代扇体沉积与油气

扇体沉积指主要由粗碎屑沉积组成的平面形态似扇形的沉积体.它是从冲积扇、扇三角洲、水下扇等环境抽象出来的一个概念.扇体沉积多分布于盆地边缘,沉积的构造背景极为相似,由于水文、气候等地理因素的差异形成了各具特色的沉积面貌.我国西北地区中新生     

砾质辫状河型冲积扇沉积微相及沉积模式:以准噶尔盆地西北缘现代白杨河冲积扇为例*

冲积扇砂砾岩储集层具有相变快、连续性差等特点,显示冲积扇内部沉积环境的复杂性。本次研究以准噶尔盆地西北缘现代白杨河冲积扇为例,在丰富的野外露头资料基础上,结合区域水文资料以及冲积扇文献资料,对白杨河冲积扇沉积演化特征及沉积模式进行探讨。按其沉积机制,白杨河冲积扇属于辫状河型冲积扇,具有规模大(扇体总面积约327.6km²)、坡度平缓(约4‰~7‰)、沉积粒度粗和漫洪细粒沉积物不发育的典型特征。在白杨河冲积扇内共可识别出16种岩相类型,并根据岩相形成的流体动力差异划归为5类成因,即重力流成因、高流态牵引流成因、低流态牵引流成因、静水沉积成因以及风成沉积成因。白杨河冲积扇扇体建造过程可划分为洪水期和间洪期2个时期,洪水期以沉积作用为主,从扇根至扇缘依次发育扇根补给水道沉积、扇根片流沉积、扇中片流沉积、扇中辫状水道沉积、扇缘径流水道沉积和扇缘湿地沉积6种沉积微相类型;间洪期以改造作用为主,从扇根至扇缘依次发育扇根主槽沉积、扇中辫状沟槽沉积和扇缘湿地沉积3种沉积微相类型。最后,依据白杨河冲积扇建立了砾质辫状河型冲积扇洪水期和间洪期的沉积模式。     

砾质辫状河型冲积扇沉积微相及沉积模式:以准噶尔盆地西北缘现代白杨河冲积扇为例

冲积扇砂砾岩储集层具有相变快、连续性差等特点,显示冲积扇内部沉积环境的复杂性。本次研究以准噶尔盆地西北缘现代白杨河冲积扇为例,在丰富的野外露头资料基础上,结合区域水文资料以及冲积扇文献资料,对白杨河冲积扇沉积演化特征及沉积模式进行探讨。按其沉积机制,白杨河冲积扇属于辫状河型冲积扇,具有规模大(扇体总面积约327.6 km~2)、坡度平缓(约4‰~7‰)、沉积粒度粗和漫洪细粒沉积物不发育的典型特征。在白杨河冲积扇内共可识别出16种岩相类型,并根据岩相形成的流体动力差异划归为5类成因,即重力流成因、高流态牵引流成因、低流态牵引流成因、静水沉积成因以及风成沉积成因。白杨河冲积扇扇体建造过程可划分为洪水期和间洪期2个时期,洪水期以沉积作用为主,从扇根至扇缘依次发育扇根补给水道沉积、扇根片流沉积、扇中片流沉积、扇中辫状水道沉积、扇缘径流水道沉积和扇缘湿地沉积6种沉积微相类型;间洪期以改造作用为主,从扇根至扇缘依次发育扇根主槽沉积、扇中辫状沟槽沉积和扇缘湿地沉积3种沉积微相类型。最后,依据白杨河冲积扇建立了砾质辫状河型冲积扇洪水期和间洪期的沉积模式。     

断陷湖泊水下扇类型与分布模式*

水下扇是断陷湖泊中一种重要沉积类型,近年来受到关注度越来越高。海洋和湖泊中与重力流有关的各类扇体的术语很多,诸如深水扇、盆底扇、湖底扇、斜坡扇、滑塌扇和浊积扇等,而它们都是不同类型的水下扇。国内沉积学界对湖泊水下扇这一术语的合理性一直有争议,与之相关的术语有水下冲积扇、近岸水下扇和远岸浊积岸等。文中梳理了有关水下扇的一些术语的含义异同,进而明确了断陷湖泊水下扇的基本类型;明确提出了湖泊外部物源体系与内部物源体系,并由此建立了湖泊水下扇的沉积分布模式;最后讨论对比了水下扇、冲积扇及扇三角洲之间的沉积差异,以期为今后深入研究这一类型沉积体提供借鉴。     

断陷湖泊水下扇类型与分布模式

水下扇是断陷湖泊中一种重要沉积类型,近年来受到关注度越来越高。海洋和湖泊中与重力流有关的各类扇体的术语很多,诸如深水扇、盆底扇、湖底扇、斜坡扇、滑塌扇和浊积扇等,而它们都是不同类型的水下扇。国内沉积学界对湖泊水下扇这一术语的合理性一直有争议,与之相关的术语有水下冲积扇、近岸水下扇和远岸浊积岸等。文中梳理了有关水下扇的一些术语的含义异同,进而明确了断陷湖泊水下扇的基本类型;明确提出了湖泊外部物源体系与内部物源体系,并由此建立了湖泊水下扇的沉积分布模式;最后讨论对比了水下扇、冲积扇及扇三角洲之间的沉积差异,以期为今后深入研究这一类型沉积体提供借鉴。     

丹霞盆地砾石统计与冲积扇体的识别

丹霞盆地是白垩纪形成的内陆山间红色盆地，主要由冲积扇体、曲流河沉积体、滨湖沉积体、浅湖沉积体和火山喷发沉积体组成，其中，冲积扇体和曲流河沉积体的岩石特征是粒度粗、成分复杂，粒度与成分在空间上变化快，较难识别。本文以剖面和钻孔资料为基础，重点研究了砾岩中的砾石特征，包括成分、形态、三轴大小、扁平砾石的产状等，用以确定扇体的物质来源方向和水体的古流向等，更好地识别冲积扇体的空间分布和冲积扇体之间的叠置关系。总体上，丹霞盆地内冲积扇体的发育具有如下规律：在盆地发育初期，冲积扇体较发育，但规模小，且多分布于盆地边缘，常和断裂活动有关。砾石主要来自附近的剥蚀区，砾石的稳定系数普遍较小，且其大小与物源区的地质时代和岩性有关。早期的冲积扇体常常和火山喷发沉积体相伴生，而后期的冲积扇体则和滨-浅湖相沉积伴生。在盆地发育晚期，冲积扇体表现为规模较大，常常和河流相沉积伴生，砾石稳定系数普遍较大。     

芦山—天全地区晚白垩世—老第三纪冲积扇—湖泊沉积组合

分布于芦山－天全地区的大溪砾岩与晚白垩世灌口组、老第三纪名山组属同期异相沉积，大溪砾岩为一大型冲积扇体，该扇体向南东逐渐过渡到以灌口组、名山组为代表的湖相沉积，系陆相盆地中一个典型的冲积扇－湖泊沉积组合实例。     

甘肃疏勒河冲积扇发育特征及其对构造活动的响应

甘肃疏勒河冲积扇是面积达2400km²的一个巨型冲积扇,位于青藏高原北缘阿尔金断裂带东端。区域构造上该扇发育在阿尔金主断裂、三危山断裂和南截山断裂组成的阿尔金断裂带左旋走滑构造域。根据野外调查获得的沉积层序、地貌形态和构造变形等资料,该冲积扇可划分为老冲积扇和新冲积扇。老冲积扇扇顶紧靠阿尔金主断裂,由已显著构造变形的早更新统玉门砾岩组成;新冲积扇是在老冲积扇基础上发育的,扇顶已向下游移动到大坝附近,距阿尔金主断裂4km,主要由中更新统酒泉砾石和晚更新统戈壁砾石组成。疏勒河冲积扇发育对区域构造活动的响应主要表现为:1)在第四纪早期,阿尔金断裂的左旋走滑兼逆冲运动,导致了由玉门砾岩组成的疏勒河老冲积扇扇头被左旋错动约8km,同时扇体,尤其扇头明显褶皱隆升,扇顶向山外移动;2)此后随着阿尔金断裂继续作左旋走滑兼逆冲运动,老冲积扇扇头又被左旋错动了约2km,总共左旋位移了约10km,并且扇顶下移了约4km,形成新的冲积扇;3)在冲积扇内从早更新世至晚更新世沉积中心不断向下游移动,呈现向下游超覆沉积的特征,这也一定程度上反映了祁连山隆升、向外扩展和侵蚀作用显著     

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.     

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).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861