Prerift and synrift sedimentation during early fault segmentation of a Tertiary carbonate platform, Indonesia     

Moyra E. J. Wilson   《Marine and Petroleum Geology》1999,16(8):262

Eocene carbonate deposits of the Barru area, Sulawesi, Indonesia, provide a rare insight into sedimentation prior to and during propagation of normal faults to the surface. Three main successions; late prerift, latest prerift/earliest synrift and synrift, are characterised by distinctive facies associations and sequence development. Shallow water foraminiferal shoals and intervening lower energy depositional environments occurred during the late prerift in areas which latter formed footwall highs and hangingwall depocentres, respectively. During the latest prerift/earliest synrift, shallow water shelves deepened laterally into slope environments in developing hangingwall depocentres. In both these sequences, sections in developing hangingwall areas are thickest, deepen up-section and thin laterally towards growing footwall highs. Active faulting resulted in rapid drowning of hangingwall depocentres and massive reworking of material derived from collapse of the platform margin and adjacent shallow water/emergent footwall highs.Differential subsidence, controlling water depths and accommodation space, types of carbonate producers and active faulting were the main factors affecting depositional environments and facies distributions. Carbonate producers are extremely sensitive indicators of depositional water depth and energy, hence rapid lateral and vertical facies variations in the Barru area provide quantifiable insight into environmental changes prior to and during active faulting.  相似文献   

廊固凹陷近岸水下扇特征及控制因素   总被引：2，自引：0，他引：2  

宋荣彩  张哨楠  董树义  周文 《地球科学与环境学报》2007,29(2):145-148,157

通过对廊固凹陷18口井541 m岩心的系统观察、156口井测井序列的建立、1km×1 km三维地震测网密度的地震相识别,分析了该沉积体系的相带展布特征。该砂砾岩层总体趋势为向上厚度减薄、层数减少,共识别出5期扇体,多呈条带状沿大兴断层断面分布,每期之间发育稳定的暗色泥岩段。该近岸水下扇的形成受3级层序、大兴断层、古构造、古气候、古地形以及物源供给等多种因素的控制。3级层序的发育特点、大兴断层的分段活动以及特殊的物源供给背景因素的匹配对近岸水下扇形成起到决定性作用。2~3期扇体扇中分布范围广,储集条件好,是凹陷下一步开发工作的有利目标。  相似文献   

Evolution and character of supra-salt faults in the Easternmost Hammerfest Basin,SW Barents Sea     

《Marine and Petroleum Geology》2015

This study investigates the evolution of supra-salt faults in the Eastern Hammerfest Basin using high–quality seismic reflection data. Traditional techniques of displacement analysis, including the variation of fault displacement (throw) against distance (x), depth (z), expansion and growth indices were adopted. Fault reactivation was assessed using bivariate plots of a) cumulative throw vs. age and b) throw (t) vs. depth of nine (9) representative faults.The interpreted faults are supra-salt crestal and synclinal faults striking NE, E and SE. These faults have complicated t-x and t-z plots and are characterized by considerable stratigraphic thickening in their downthrown section. Faults in the study area have developed over the salt structure since latest Paleozoic times; some of them were reactivated by Early to Middle Triassic through dip linkage of initially isolated fault sets. Along strike, the fault exhibit complex segmentation through coalescence of several subunits linked by local throw/displacement minima. Expansion and growth indices show that the faults of the study area developed during the deposition of Paleozoic to Early Cretaceous sediments by polycyclic growth involving both blind and syn-sedimentary activity.An important piece of information from this study is that fault propagation is controlled by lithological heterogeneity and that both lateral and vertical segmentation of faults are important for hydrocarbon migration within the Triassic to Late Cretaceous interval.  相似文献   

High-pressure granulite from Western Kunlun,northwestern China: Its metamorphic evolution,zircon SHRIMP U-Pb ages and tectonic implication   总被引：1，自引：0，他引：1  

QU JunFeng  ZHANG LiFei  AI YongLiang  L Zeng  WANG JianPing  ZHOU Hui & WANG ShiYan MOE Key Laboratory of Orogenic Belts  Crustal Evolution  School of Earth  Space Science  Peking University  Beijing  China  Henan Polytechnic University  Jiaozuo  China  Geological Survey of Henan Province  Zhengzhou  China 《中国科学D辑(英文版)》2007,50(7):961-971

High-pressure mafic granulites occurring as lenticular bodies within garnet-amphibolites in Kangxiwar Fault have been first reported in this paper. The P-T conditions of two metamorphic stages were ob-tained using calibrated geothermal barometers and ThermoCalc Program. The peak metamorphic con-dition of these high-pressure granulites is about 760―820℃,1.0―1.2 GPa and the retrograde meta-morphic condition is about 620―720℃,0.7―0.8 GPa. The petrological studies show that they have a near-isobaric cooling P-T...  相似文献   

云南武定荒箐铁铜多金属矿矿床成因     

朱晖  周元昆  李迅  周丽英  赵云 《云南地质》2010,29(1):53-55,52

矿床产于断层破碎带中,受断层和地层层位控制,与迤纳厂矿床具有一定的相似性。铁矿为中低温热液裂隙充填型脉状矿床,而铜矿床应为沉积——变质型。  相似文献   

抽水作用下先期断裂对地裂缝的影响研究   总被引：1，自引：0，他引：1  

蒋臻蔚  彭建兵  王启耀 《工程地质学报》2010,18(5):651-656

过度抽取地下水和先期存在的断裂构造是西安市地裂缝地质灾害发生的主要原因。作者首先从理论上分析了抽水情况下地裂缝形成的张拉破裂机制、剪切破裂机制和张剪复合破裂机制,并从结构面控制理论分析了先期断裂在地裂缝形成中的控制作用;然后依据比奥三维固结理论,采用FLAC软件建立了西安地裂缝的计算模型,比较了抽水作用时没有先期断裂和地层差异、有先期断裂而没有地层差异、有地层差异而无先期断裂等情况时的地面变形特征,得出抽水作用下,先期断裂对地裂缝的形成及发展具有诱导、隔离和放大的耦合作用,从而得出先期断裂不仅仅只是地裂缝形成的构造基础的结论。  相似文献   

八宝山断裂带浅部岩体水力耦合模型          下载免费PDF全文

王旭升  王广才  董建楠 《地学前缘》2010,17(6):141-146

八宝山断裂带是北京西部的一条活动断裂,观测表明其形变、地下水位和降水之间存在强相关性。从大灰厂观测站的断裂带条件和观测系统布置来判断,这种强相关性是浅部破碎岩体渗流-应力耦合机制的结果。断裂带浅部岩体可以分为无压区和承压区。降水能够直接入渗补给无压区,也能够渗入到承压区上部的上盘岩体风化带,从而同时影响断裂带和风化带的地下水位。一个7参数的线性水力耦合模型给出了与实测动态基本一致的垂向形变、地下水位模拟结果。模型分析表明观测到的垂向变形主要由无压区地下水位升降引起的膨胀和收缩变形构成,而上盘湿润或疏干引起的重量变化对垂向变形贡献很小。由于断裂带的地下水排泄基准面和水准基台值可能存在某种外在因素引起的变化,模型参数可能不够稳定,需要进一步调查研究。  相似文献   

黑龙江省中西部地球排气与地震活动的探讨   总被引：5，自引：1，他引：4  

邵济安  赵谊  张福松  陆永发 《岩石学报》2010,26(12):3651-3656

本文根据近两年来在黑龙江省中西部沿断裂带逸出的H2、CO、H2S等还原性气体组合,结合C、H、S、He、Ar同位素研究,讨论了还原性气体组合的深源特征。在此基础上以安达地震为例,作者阐明了以氢气为首的还原性气体逸出与深部构造背景及其与地震的关系。深源还原性气体的逸出孕育着地壳不稳定的因素,有诱发地震和其他自然灾害的可能。地球排气作用与地震作用关系的研究在类似黑龙江省中西部大面积被第四系覆盖的地区是地震预报较为有效的手段。  相似文献   

云南省施甸县摆田铅锌矿矿床地质特征及成因     

李星  王睿  和敬华  徐友智  胡兴涛 《云南地质》2014,(2):207-209

矿体赋存于上三叠统大水塘组顶部与中三叠统河湾街组底部断层接触带中,严格受构造控制.矿体呈透镜状～似层状,厚度变化较大.为一早期形成于断裂破碎带中后经地表长时间氧化淋滤叠加形成的热液—风化淋滤型铅锌矿床.  相似文献   

Evolution of neotectonic activity of East Anatolian Fault System (EAFS) in Bingöl pull-apart basin,based on fractal dimension and morphometric indices     

《Journal of Asian Earth Sciences》2014

This study is an attempt of a semi-automatic geomorphological GIS analysis based on morphometric indices. In the study, 10-m-resolution Digital Elevation Models (DEMs) are used to assess the neotectonic signals regarding the recent topographic developments and to attach additional significance to active tectonics in the Bingöl basin area. The methodology incorporates the determination of the structural similarities of the faults in the basins using fractal concepts and the application of four morphometric indices (Stream Power Index (SP), Multi-resolution Index of Valley Bottom Flatness (MRVBF), Terrain Ruggedness Index (TRI) and Valley Width-to-Height Ratio (Vf)). In order to detect the deviation from spatial randomness of the applied indices, the weighted correlation coefficient Moran’s I is used and the results are interpreted at a confidence interval of 99%. The spatial distribution of integrated index values is evaluated with the tectonically active fault zones in order to determine the probable activity and the structural deformation in the basin.The applied methodology reveals that the fractal analysis of the fault lines and the spatial analysis of the morphometric indices proved to be effective tools in analyzing the tectonic influence of the fault system on the basin area. Within the basin area, a relatively lesser degree of tectonic activity is observed, in contrast with the high tectonic activity outside the basin.  相似文献