Facies architecture in a tectonically influenced estuarine incised valley fill of Miocene age, northern Brazil     

Dilce F. Rossetti  Antnio E. Santos Júnior 《Journal of South American Earth Sciences》2004,17(4):1032

The Miocene Barreiras Formation in the Middle Rio Capim area records an incised valley system for which facies analysis and ichnology (Skolithos, Ophiomorpha, Planolites, Gyrolithes, Taenidium) suggest an estuarine character. Three stratigraphic units are recognized (from bottom to top): Unit 1 includes an inner estuarine tidal channel complex and tidal flat/salt marsh deposits; Unit 2 consists of estuarine bay/lagoon and flood tidal delta deposits related to the estuary mouth; and Unit 3 includes a tidal channel with a tidal point bar, as well as tidal flat/salt marsh deposits similar to those from Unit 1. These units and their bounding surfaces record the history of relative sea level changes in the estuary. After a sea level drop, the valley was inundated and formed an amalgamated sequence boundary and transgressive surface. Transgression (Unit 1) promoted the landward shift of flood tidal deltas and lagoon settings (Unit 2). The system then moved seaward, with the superposition of inner estuarine deposits (Unit 3) over Unit 2. Facies architecture seems to have been controlled by tectonics, as shown by: the paleovalley orientation according to the main tectonic structures of the basin; the presence of faults and fractures that displace the basal unconformity; and the abundance of soft sediment deformation.  相似文献   

中国南方海相石油地质特征及勘探潜力   总被引：14，自引：0，他引：14  

马永生  郭彤楼  付孝悦  肖朝晖 《海相油气地质》2002,7(3):19-27

中国南方及邻区的基本构造格架可概括为五个陆缘造山带、三个较稳定地块、一个加里东构造域和一个陆内基底拆离造山带。基本地层层序格架可归纳为六个一级层序及相应的沉积构造旋回,沉积构造格架及多旋回构造演化史决定了南方海相石油地质的基本特征。自震旦纪至中三叠世在南方发育了两个世代的海相原型沉积盆地,均在南北两大陆边缘发育了丰富的优质烃源岩,包括四套区域主力烃源层和六套地区性烃源岩,并形成五套好的区域性盖层以及包括风化壳、裂缝、礁滩及白云岩等多种储集体。印支—早燕山造山期原型大陆边缘盆地和前陆盆地,曾形成五个原始超油气系统,后期的高热演化,使其在现今多转化为含气系统。现实的含气系统只能残留赋存于现今有效保存单元之内,具有多源多期成烃、晚期复合成藏等基本特点。近期油气资源评价认为,南方海相资源量为8.2882×10~(12)m~3气当量,油气勘探潜力大。今后的有利勘探方向包括鄂西渝东地区及川东北地区等七个区块。  相似文献   

欠发达山岳区旅游资源层次性开发研究--以湖南省九嶷山风景区为例   总被引：2，自引：0，他引：2  

许树辉  叶乐安  刘德威 《热带地理》2002,22(1):66-70

21世纪旅游业将成为我国经济发展的重要产业。欠发达山岳区旅游资源丰富 ,开发潜力大。落后的经济状况客观上要求欠发达山岳区旅游资源应实行层次性开发。探讨了欠发达山岳区旅游资源层次性开发的依据和理论构架 ,并结合九嶷山风景区旅游资源层次性开发进行了实证分析  相似文献   

Application of sequence and genetic stratigraphic concepts to Carboniferous coal-bearing strata: an example from the Black Warrior basin,USA     

Robert A. Gastaldo  Timothy M. Demko  Yuejin Liu 《International Journal of Earth Sciences》1993,82(2):212-226

Carboniferous strata provide an excellent example on which to test the application of genetic stratigraphic and sequence stratigraphic concepts. Both approaches are employed in the evaluation of the coal-bearing strata of the Black Warrior basin, south-eastern USA. Bounding hiatal surfaces have been recognized in the succession of rock that includes the Mary Lee coal zone. Within the framework of genetic stratigraphy, one genetic sequence has been identified comprised of offlap (progradational and aggradational facies) and onlap (aggradational and transgressive facies) components. Seven parasequence sets have been delimited according to the concepts of sequence stratigraphy. These have been ascribed to transgressive, highstand and shelf margin systems tracts. The identification of components of these contrasting frameworks provide the basis for evaluating other Carboniferous strata. Correspondence to: R. A. Gastaldo  相似文献   

Sequence stratigraphy in a mixed carbonate-silicilastic depositional system (Middle Miocene; Styrian Basin,Austria)     

J. Georg Friebe 《International Journal of Earth Sciences》1993,82(2):281-294

The mixed carbonate-siliciclastic Weißenegg (Allo-) Formation records three depositional sequences corresponding approximately to the TB 2.3, TB 2.4 and TB 2.5 global cycles. Sea-level fluctuations were of the order of at least 30 m. Siliciclastic lowstand systems tracts comprise lignite deposits, reworked basement and tidal siltstones (above a tectonically enhanced sequence boundary) as well as coastal sand bars. Coastal sands of the transgressive systems tract contain distinct layers of well cemented nodules. They are interpreted as the first stage in hardground formation and record superimposed minor sea-level fluctuations. Coral patch reefs and rhodolith platforms developed during transgressive phases and were subsequently drowned and/or suffocated by siliciclastics during early highstand. Shallowing upwards siliciclastic parasequences, each terminated by a bank of rhodolith limestone, form the (late) highstand systems tract. The limestone beds record superimposed fourth-order transgressive pulses. Occasionally a carbonate highstand wedge developed. Lowstand carbonate shedding occurred where the top of a platform which suffered incipient drowning during highstand was near sealevel again during the following lowstand. Late highstand delta progradation is common.  相似文献   

滇黔桂区中三叠世安尼期浊积岩微相划分与金矿关系   总被引：2，自引：0，他引：2  

杨成奎 《矿产与地质》1993,7(1):23-28

对滇黔桂区中三叠世安尼期浊积岩微相的划分,认为区内浊流有3处发源地,形成了3个浊积扇,每一扇中又由中心相、过渡相及末梢相组成,从各微相分布特征和含金性分析,认为浊积岩的过渡相与卡林型金矿密切,并提出了找矿方向.  相似文献   

新疆巴里坤湖35000年来古气候变化序列   总被引：24，自引：1，他引：24  

韩淑ti  袁玉江 《地理学报》1990,45(3):350-362

对巴里坤湖ZK00A钻孔剖面用多种手段进行同步同周期的综合研究。古气候变化格局以各种不同时间尺度、不同程度的冷湿期和暖干期交替变化为特征。冷湿期与冰期、高湖面期对应;暖干期与间冰期、低湖面一致。整个剖面揭示出35000年来具有12个10~3年、3个10~4年、3个10~2年的气候旋回。其中12000年以来以暖干为主,12000年前以冷湿为主。存在着600、2225—2543、5933—8900、11600年的变化周期。对内陆干旱区,35000年以来的气候变化序列、格局和周期的研究,以大量气候标志、参数为依据,经计算机处理与成图,具有较高的可信性。  相似文献   

大同－阳高两次地震的对比分析   总被引：3，自引：0，他引：3  

刘巍  安卫平  赵新平 《地震研究》1994,(1)

１９８９年１０月，１９９１年３月，在山西北部大同盆地先后发生Ｍｓ６．１、Ｍｓ５．８两次中强地震。对比这两次地震的序列、空间分布及能量释放等存在很大差异。两次地震属同一地震序列，５．８级地震的活动规律具有晚期强余震的特点，是６．１级地震活动的一次大的起伏。进一步分析表明，大同—阳高的两次地震活动，以及在此期间山西地区发生的一系列５级左右地震活动，是华北地区区域应力场增强，较大范围内应力增加和传递的结果。  相似文献   

High-frequency cycles in the upper Aptian carbonates of the Organyà basin,NE spain     

M. Bachmann  H. Willems 《International Journal of Earth Sciences》1996,85(3):586-605

High-frequency cycles in Upper Aptian carbonates have been studied on the carbonate ramp of Organyà (southeastern Pyrenees). The depositional area comprises a shallow marine to deeper marine transect. A detailed facies model is developed subdividing the transect into an inner ramp area (above fairweather wave base), a mid-ramp area (between fairweather wave base and storm wave base) and an outer ramp area (below storm wave base). Based on microfacies analysis a cyclostratigraphic and sequence stratigraphic interpretation is established. Variations of the sedimentary patterns within different sections of the homoclinal ramp are due mainly to sea level changes. Sea level changes of third and fourth order are reflected by the shifting of the shallow subtidal facies belts up and down the ramp. The study of fifth-order sea level changes is based on statistical methods (quantitative facies analysis and principal component analysis). The ratio of the fourth- and fifth-order cycles is very similar to the well-known ratio of the eccentricity (100 ka) and the precession (18.6/22.5 ka). The absolute age values derived from the cyclostratigraphy fit into the biostratigraphic framework. Thus, a global eustatic control is assumed to be responsible for the cycles of higher frequency. The lower frequency third-order sequences, however, were considerably influenced by local tectonic processes.  相似文献   

测井地质学新进展   总被引：3，自引：5，他引：3  

李庆谋  杨峰 《地球物理学进展》1996,11(2):66-80

八十年代以来，测井技术的迅速发展，油气、煤田勘探开发的需要，层序层学理论的出现以及其它相关学科的进展已迅速速推动与拓展了测井地质学的研究范围。表面在传统测井地质，如地层压实、有机质含量坟取、用测井资料确定财性、岩相、沉积环境研究等有了更新的概念。  相似文献