北祁连阿柔地区石炭纪层序地层研究及其找矿意义     

徐均强  徐伟祥  杜韦 《山东国土资源》2015,31(7)

石炭纪地层是该地区分布最广泛的地层之一,因其为一套含煤地层,其沉积特征的研究对煤矿找矿工作非常重要。根据其岩石组合特征划分为2个组即臭牛沟组和羊虎沟组,多受NW—SE向断裂影响,而沿构造方向展布,其顶底一般发育齐全,通过对其层序地层的研究,认为在石炭纪地层发育时期,该区经历了2次较完整的海水入侵及退出的过程,其中的煤矿与第2个海侵体系域发育程度密切相关。  相似文献   

2010年4月14日玉树7.1级地震前异常特征及强震动力学关系探讨     

马玉虎  陈玉华 《中国地震》2011,27(2):136-146

系统地分析了2010年4月14日玉树7.1级地震的地震活动性异常、前兆异常以及震前动物反常行为.研究表明,玉树7.1级地震前异常并不丰富,但觉察到的异常突出.其中中长期异常有6级、5级和4级的平静区;前兆观测有玉树表层水温、德令哈表层水温和平安电磁波等显著异常;同时震前1周还存在数量较多的动物宏观异常现象;主震前130min发生了一次4.7级地震.结合1996年以来巴颜喀拉地块边界的强震震源机制解,探讨了玉树地震孕育的动力学过程.结果表明,1996年喀喇昆仑山口7.1级、1997年玛尼7.5级和2010年玉树7.1级地震是同一动力学过程下的强震事件,且中长期存在的不同震级档平静区演化可能与上述动力学过程有关.还对强震原地复发、前震识别和玉树地震中的前兆观测等科学问题进行了讨论.  相似文献   

Ichnology, sequence stratigraphy and depositional evolution of an Upper Cretaceous rocky shoreline in central Chile: Bioerosion structures in a transgressed metamorphic basement     

Luis A. Buatois  Alfonso Encinas 《Cretaceous Research》2011,32(2):203-212

Exposures of upper Paleozoic slates of the metamorphic basement near Concepción, central Chile, are covered by transgressive deposits belonging to the Upper Cretaceous Quiriquina Formation. Presence of clusters of the bivalve boring Gastrochaenolites isp. at the irregular and erosive contact between these two units indicates the development of an ancient rocky shoreline, illustrating a rare example of bioerosion in a metamorphic substrate. Coarse-grained deposits mantling the bioeroded surface represent a transgressive lag produced due to ravinement. In sequence-stratigraphic parlance, the bioeroded surface is classified as a FS/SB or co-planar surface formed due to amalgamation of erosion during lowstand and the subsequent transgression. Unburrowed trough cross-bedded upper-shoreface to intensely bioturbated middle-shoreface deposits record continuous transgression. Logs bioeroded by Teredolites clavatus are also present. Middle-shoreface deposits are dominated by deep Ophiomorpha isp., commonly showing laminated infill. Thalassinoides suevicus occurs locally. Intense bioturbation also suggests that the shoreface developed in embayed shorelines, protected from oceanic waves. While rocky shorelines in limestone are characterized by a high abundance and diversity of bioerosion structures, those formed in other types of substrates contain less diverse, commonly monospecific, suites of borings. In terms of Seilacherian ichnofacies, the bioerosion structures analyzed are attributed to a low-diversity expression of the Trypanites ichnofacies. It is proposed that the Trypanites ichnofacies thus may display two expressions: an archetypal one characterized by high diversity in carbonate substrates, along with a depauperate expression in other types of substrates (e.g., metamorphic and igneous rocks). The extreme hardness of the substrate is regarded as the stress factor responsible for the reduction in ichnodiversity.  相似文献   

塔里木盆地肖尔布拉克上震旦统苏盖特布拉克组层序界面与沉积相   总被引：1，自引：0，他引：1       下载免费PDF全文

钱一雄  尤东华  陈代钊  陈跃  姜海健  刘忠宝 《地质科学》2011,46(2):445-455

震旦纪是塔里木盆地被动大陆边缘盆地重要发育期.通过对阿克苏肖尔布拉克剖面中的上震旦统苏盖特布拉克组实测工作,利用层序地层学和沉积相分析方法,提出了苏盖特布拉克组发育了海侵不整合、陆上暴露不整合和隆升侵蚀不整合面等Ⅱ-Ⅲ(Ⅳ)层序界面成因类型;揭示了下亚段(潮坪)滨岸-浅海沉积体系中的潮间-潮上、滨岸沙丘、风暴等沉积;上...  相似文献   

大型内陆拗陷湖盆层序结构充填特征及其分布规律——以鄂尔多斯盆地延长组为例   总被引：1，自引：1，他引：0  

赵俊兴  申赵军  李良  王峻  王峰  曹志松 《岩石学报》2011,27(8):2318-2326

近年来层序地层学的发展为我们进行盆地分析提供了新思路,应用沉积学和高分辨率层序地层研究方法,将盆地晚三叠世延长组划分出4个长期、22个中期基准面旋回。整个盆地在延长期的"沉积-层序-构造"演化史表现为:LSC1构造初始沉降、湖泊形成:LSC2湖盆快速坳陷,晚期湖泊进入鼎盛期;进入LSC3,盆地周缘构造趋于稳定、盆地开始填平补齐期,湖泊开始充填淤浅; LSC4期河流沉积作用增强,盆地进入超补偿沉积阶段,湖泊被淤塞并进入残余湖泊沉积期。提出并定义了层序结构动力学概念,认为层序结构动力学是在研究层序充填过程中由于构造运动、海平面变化、物源供给、气候、沉积作用等因素控制影响层序结构发育特征及其分布规律的一门学科。在对鄂尔多斯盆地延长组层序地层综合划分基础上,根据一个基准面变化周期中所形成的层序结构变化特征,将层序结构划分出5种基本层序结构单元类型,即A型、B1型、B2型、B3型和C型等5种。针对对鄂尔多斯盆地延长组不同地理位置、不同沉积体系单元具体分析了层序充填结构特征、结构类型、层序充填动力学过程,层序结构发育类型及充填过程,探讨了大型内陆拗陷盆地层序结构动力学特征。首次提出了"层序结构分布律",建立了鄂尔多斯盆地延长组大型内陆拗陷湖盆层序结构分布模式,认为在没有重大构造事件、突发沉积事件发生的情况下,只有那些相邻的层序结构类型才能相互重叠地分布。  相似文献   

生物礁内部地震反射特征的地质解读及以体系域为单元的层序地层学认识——以珠江口盆地生物礁为例     

黄诚  傅恒  房晓璐  陶碧娥  刘雁婷 《海相油气地质》2011,16(2):47-52

通过分析珠江口盆地东沙隆起生物礁生长方式对海平面变化的响应,归纳出不同时期礁体生长的几种可能的几何形态和相应的地震响应特征,并对生物礁内部地震反射特征进行地质解读,建立了成礁模式,获得以体系域为单元的生物礁层序地层认识,为层序划分和层位对比解释提供了较可靠的参考.  相似文献   

The Central Submarine Canyon in the Qiongdongnan Basin, northwestern South China Sea: Architecture, sequence stratigraphy, and depositional processes   总被引：7，自引：0，他引：7  

Chenglin Gong  Yingmin WangWeilin Zhu  Weiguo LiQiang Xu  Jinmiao Zhang 《Marine and Petroleum Geology》2011,28(9):1690-1702

Submarine canyons have been the subject of intense studies in recent years because of their close link to deepwater systems. The Central Canyon is a large unusual submarine canyon in the northwestern margin of the South China Sea, has a total length of about 425 km and is oriented sub-parallel to the continental slope. Using integrated 2D/3D seismic, well log, core, and biostratigraphy data, the current study documents the stratigraphic framework, internal architecture, depositional processes, and controlling factors of the segment of the Central Canyon located in the Qiongdongnan Basin.The integrated analysis shows that the canyon fill consists of four 3^rd-order sequences, SQ4, SQ3, SQ2, and SQ1. Each of them is bounded by regionally important erosional surfaces (3^rd-order sequence boundaries). Within each 3^rd-order sequence there is maximum regressive surface separating a regressive systems tract in the lower part and a transgressive systems tract in the upper part. Nine facies are identified and are further grouped into five depositional units, DU1 through DU5.The canyon evolved through four cut-and-fill stages, with a change from predominantly axial cut-and-fill to primarily side cut-and-fill. Axial cut-and-fill dominated during the first stage, and the slope-subparallel paleo Xisha Trough was intensely eroded by large-scale axial gravity flows. During the second cut-and-fill stage, the Central Canyon experienced both axial and side cut-and-fill. The third stage was dominated by side cut-and-fill. The canyon was eroded and fed by slope channels that transported sandy sediments from the shelf to the north during regression, and was covered by side-derived muddy MTCs during transgression. The last stage was also dominated by side cut-and-fill. The canyon, however, was filled predominantly by side-derived muddy MTCs.Evolution and depositional processes in the Central Canyon were likely controlled by slope-subparallel negative-relief induced by paleo-seafloor morphology, structural inversion of the Red River Fault and the slope-subparallel basement faults. Additionally, Coriolis force, sea-level fluctuations, high sedimentation rate, and rapid progradation of the slope also controlled and influenced the depositional processes, and internal architectures of the canyon.  相似文献   

1999年11月29日岫岩—海城5.6级地震成功预报的科学总结   总被引：6，自引：0，他引：6  

于龙伟  李芳 《东北地震研究》2000,16(2):14-26

总结了岫岩－海城５．６级地震成功预报的科学依据，其中包括对地震活动背景分析、震前地震学异常分析、前震序列的科学判定、余震序列实时的跟踪研究、临震预报的技术决策过程、前兆异常的临震性质和成功预报的社会效益和经济效益等。并对这次地震的成功预报的主要判据和余震序列分析中的成功与不足作了较为客观的评价。  相似文献   

Late Cretaceous calcareous nannofossil and planktonic foraminiferal bioevents of the shallow-marine carbonate platform in the Mitla Pass, west central Sinai, Egypt     

Sherif Farouk  Mahmoud Faris 《Cretaceous Research》2012,33(1):50-65

The first detailed biostratigraphic analyses of the Coniacian-middle Campanian shallow-marine carbonate successions exposed in the Mitla Pass, west central Sinai, Egypt have revealed the stratigraphic distribution of diverse calcareous nannofossil and planktonic foraminiferal species. Thirty-six calcareous nannofossils and thirty-two planktonic foraminifera are identified, indicating a Coniacian to middle Campanian age and four Tethyan planktonic foraminiferal and five calcareous nannofossil zones. A comparison of these bioevents from different palaeolatitudes shows considerable variation in age.Three sequence boundaries coincident with the Turonian/Coniacian, Coniacian/Santonian and Santonian/Campanian stage boundaries are recognized. A fourth sequence boundary is marked by a major upper Campanian to early Ypresian (early Eocene) unconformity. These sequence boundaries are primarily related to regional tectonism associated with the Syrian Arc Fold System and secondarily to eustatic sea-level fluctuations.  相似文献   

浅谈赣东北上二叠统龙潭组层序地层、古地理与乐平煤     

徐克定 《海相油气地质》2012,(2):34-44

赣东北上二叠统龙潭组为一个完整的准二级层序,含15个三级层序,按体系域分七个阶段描述了古地理特点。垂向上水体由浅至深再至浅,横向上南浅北深,有官山段上部、狮子山段、王潘里段上部三个障壁形成期。赣东北龙潭期含煤建造,多数是在潮汐为主的水动力条件下形成的,成煤环境与潮汐带伴生在一起,不同成煤环境形成不同的煤。退积型平缓潮坪,分内、中、外三种亚环境,分别形成富镜质组树皮煤、贫镜质组树皮煤、富镜质组含树皮煤;障壁后潮坪形成富镜质组富树皮煤;三角洲平原和滩脊带形成腐植煤。真正质量最好的乐平树皮煤,只发育在退积型平缓潮坪的中带。不同类型的煤,生烃条件大不相同。  相似文献