Channelized debris‐flow deposits and their impact on turbidity currents: The Puchkirchen axial channel belt in the Austrian Molasse Basin     

DONALD R. LOWE 《Sedimentology》2012,59(7):2042-2070

Deposits of submarine debris flows can build up substantial topography on the sea floor. The resulting sea floor morphology can strongly influence the pathways of and deposition from subsequent turbidity currents. Map views of sea floor morphology are available for parts of the modern sea floor and from high‐resolution seismic‐reflection data. However, these data sets usually lack lithological information. In contrast, outcrops provide cross‐sectional and lateral stratigraphic details of deep‐water strata with superb lithological control but provide little information on sea floor morphology. Here, a methodology is presented that extracts fundamental lithological information from sediment core and well logs with a novel calibration between core, well‐logs and seismic attributes within a large submarine axial channel belt in the Tertiary Molasse foreland basin, Austria. This channel belt was the course of multiple debris‐flow and turbidity current events, and the fill consists of interbedded layers deposited by both of these processes. Using the core‐well‐seismic calibration, three‐dimensional lithofacies proportion volumes were created. These volumes enable the interpretation of the three‐dimensional distribution of the important lithofacies and thus the investigation of sea floor morphology produced by debris‐flow events and its impact on succeeding turbidite deposition. These results show that the distribution of debris‐flow deposits follows a relatively regular pattern of levées and lobes. When subsequent high‐density turbidity currents encountered this mounded debris‐flow topography, they slowed and deposited a portion of their sandy high‐density loads just upstream of morphological highs. Understanding the depositional patterns of debris flows is key to understanding and predicting the location and character of associated sandstone accumulations. This detailed model of the filling style and the resulting stratigraphic architecture of a debris‐flow dominated deep‐marine depositional system can be used as an analogue for similar modern and ancient systems.  相似文献   

青藏高原东缘盐源盆地古近纪风成沙丘及其古地理意义^*          下载免费PDF全文

崔晓庄  江新胜  伍皓  熊国庆  卓皆文  陆俊泽 《古地理学报》2012,14(5):571-582

盐源盆地始新世丽江组沉积时期发育了一套具大型高角度交错层理的红色砂岩,其确切成因对于厘定青藏高原东缘古近纪古地理格局、恢复东亚新生代干旱带与古气候演化过程具有重要意义。文中通过对盐源盆地始新统丽江组红色砂岩的沉积特征进行系统分析,证明该套砂岩的岩性、粒度分布、石英颗粒表面特征与沉积构造等明显不同于水成沉积,而与典型风成沙丘相应特征完全一致,表明其为风成沙丘沉积。结合古近纪研究区的古气候条件、大气环流样式与大地构造背景,笔者进一步推断盐源盆地始新世风成沙丘可能沉积于中国古近纪干旱带内的沙漠环境。根据目前相关研究资料,确认青藏高原东缘存在一个厚度稳定的古近纪风成沙丘富集带。  相似文献   

黔北—渝南地区中二叠世早期梁山组的岩相古地理特征和铝土矿成矿效应   总被引：1，自引：0，他引：1  

张启明  江新胜  秦建华  崔晓庄  刘才泽 《地质通报》2012,31(4):558-568

研究区位于扬子陆块上扬子区,中二叠世早期地层梁山组产有丰富的沉积矿产,其中铝土矿具有良好的勘探开发前景。为了揭示区内中二叠世早期铝土矿的形成、分布与岩相古地理的关系,对区内梁山组的沉积特征、展布规律和含矿性进行了研究,编制了中二叠世早期梁山组岩相古地理图,提出了区内铝土矿障壁后泻湖成矿的模式。结果表明,区内古地理格局具有北高南低、南海北陆的特点,鲁甸—威宁—贵阳—都匀一线为障壁沉积体系,北部为障壁后泻湖沉积体系,南部为正常浅海沉积体系,大致可划分为隆起、滨湖、浅湖、半深湖—深湖、障壁砂坝、内陆棚和外陆棚7个沉积亚相,铝土矿矿床全部分布于北部泻湖半深湖—深湖相区内,岩相古地理控矿作用明显。  相似文献   

藏北雁石坪夏里组高频岩相旋回的驱动机制研究          下载免费PDF全文

文军  伊海生  邱余波  吴池华  龚大兴 《沉积与特提斯地质》2012,32(1):44-49

Walsh频谱分析引用不连续的方波代替傅里叶频谱分析中连续的正弦波和余弦波,由于Walsh函数的不连续性,它广泛应用于地层旋回周期的检测。藏北雁石坪地区中侏罗统夏里组发育一套以砂岩、泥岩为主的高频岩相旋回,在地层颜色上也表现出较好的旋回性。对该组地层岩性和颜色进行Walsh频谱分析对比发现,岩性频谱曲线及颜色频谱曲线的主频周期与米兰科维奇旋回周期之间均具有极好的对应关系,认为海平面的周期性变化是夏里组高频岩相旋回的驱动机制。同时根据岩性旋回频谱和颜色旋回频谱计算得出夏里组的沉积速率约为0．111m／ka,沉积持续时间约为3．689Ma。  相似文献   

渝东—湘西地区志留纪小河坝组层序岩相古地理特征及演化   总被引：1，自引：0，他引：1  

朱志军  陈洪德  林良彪  侯明才 《地层学杂志》2012,(3):662-671

通过对渝东—湘西地区野外露头及相关室内研究,分析了区内志留纪小河坝组沉积环境、层序特征、沉积相展布及其演化特征。将该区小河坝组划分为2个沉积层序,每个沉积层序都由海侵和高位体系域组成。以体系域为编图单元,采用体系域压缩法,编制了渝东—湘西地区小河坝组4张层序岩相古地理图,结果表明:更加精确真实地反映了海陆分布、物源方向及其演化过程,更好地反映了层序格架下的物质聚集分布规律。揭示出研究区早志留世小河坝期碎屑岩沉积的物质主要来自东南部的江南雪峰山隆起,沉积环境由东往西逐渐变深,三角洲平原位于湘西地区,三角洲前缘发育于渝东地区;碳酸盐台地发育于靠近黔中隆起的南部浅水区,沉积环境由南往北逐渐变深,深水陆棚沉积区位于宜宾—重庆一带,该新认识对于更准确地预测渝东-湘西志留系储集体的分布以及下一步油气勘探部署具有重要实际指导意义。  相似文献   

Derivation of the Chortis and Chiapas blocks from the western Gulf of Mexico in the latest Cretaceous–Cenozoic: the Pirate model     

《International Geology Review》2012,54(15):1765-1775

Currently, two basic models describe the genesis of the Caribbean Plate: (i) a Pacific model that derives the Caribbean Plate off southern Mexico and (ii) an in situ model. The Pacific model requires the 1100–1400 km sinistral displacement recorded across the Cayman Trough to pass through the Gulf of Tehuantepec into the Middle America Trench, but no evidence of such a connection exists. The in situ model is inconsistent with the 1100–1400 km displacement across the Cayman Trough. A way through this impasse is indicated by the northwestward curvature of active oblique reverse to sinistral transcurrent faulting in southeast Mexico. Extending this potential solution back to ca. 80 Ma forms the basis of the new Pirate model, in which the Caribbean Plate and the Chortis and Chiapas blocks are derived from the northwest by anticlockwise rotation during the latest Cretaceous and Cenozoic. Following passage of the Chortis Block, the northern and southern parts of the Yucatan block collided along the intra-Yucatan suture, producing the 11–9 Ma Chiapas fold-and-thrust belt. The Pirate model accounts for the N-trending segment of the Laramide Sierra Madre Oriental–Zongolica foldbelts by anticlockwise drag, Palaeogene palaeocanyons, the second, 66–40 Ma phase of rifting in the western Gulf of Mexico, and post-10 Ma extension in the Chortis Block (Chortis–Sula rift province). Impingement of the East Pacific Rise on the Middle America Trench led to modification of the Pirate model involving subduction erosion of the ～200 km-wide, Eocene–Oligocene forearc at ca. 25 Ma, opening of the Gulf of California at ca. 6 Ma, and birth and ESE movement of the Southern Mexico block (<5 Ma) followed by its fragmentation. The Pirate mechanism indicates that the North American Plate is relatively weak and so tears and rotates into the trailing edge of the Caribbean Plate.  相似文献   

非常规油气藏地质建模与数值模拟一体化技术研究     

吕雪祥 《中国煤炭地质》2012,(8):85-91

非常规油气藏地质建模与数值模拟是通过对地质、地震、油藏综合研究,建立储层精细地质模型。首先建立构造模型,同时运用地震反演的成果结合单井岩相数据建立岩相模型,利用钻井泥浆漏失、油气田和单井的实际生产情况和微地震监测,描述油气藏内发育的天然裂缝和人工压裂裂缝,最终利用岩相模型控制建立孔隙度和饱和度等属性模型,为数值模拟提供能够反映与实际地质情况相符的三维油气藏粗化地质模型。在此模型的基础上,进行生产历史拟合、产量预测,并制定合理的开发方案。  相似文献   

鄂尔多斯盆地西缘麻黄山地区延8储层特征   总被引：2，自引：0，他引：2  

丁晓琪  张哨楠  刘朋坤  邓礼正 《西安地质学院学报》2010,(1):65-69

通过对延8储层铸体薄片、扫描电镜、孔渗测定、压汞资料等分析,延8储层具有以下特征：研究区北边富长石、南边富石英,具有不同的物源;砂岩粒度以中粒为主,细粒和粗粒次之;主要的储集空间为粒间孔和粒内溶孔;由于大量的长石、岩屑被溶,孔隙度、渗透率不呈正态分布,均偏大,溶蚀作用形成的大量微孔造成高束缚水饱和度,产纯油或含水率极低;砂体厚度、岩石相和成岩作用共同控制着储集层的物性。结果表明,位于河道中部弱胶结的中砂岩具有良好的储集性能。  相似文献   

山东莱州三仓成矿带地质特征与构造岩相研究     

郭彬  刘帅  陈自辉 《矿产与地质》2010,24(5):395-398

三山岛—仓上成矿带位于山东省莱州市境内,其地质条件优越,成矿条件良好,是我国著名的金矿成矿带。本文主要介绍了该成矿带的地质特征与构造岩相特征,总结和分析了该矿带内矿床的矿物组合、结构构造、成矿阶段等;并对该成矿带的构造岩相带分布、地球化学元素组合、稳定同位素、蚀变带形成时代等进行了研究;在宏观上指出了有利成矿的区段和部位,确定了构造变形岩相带的成矿远景区,对该成矿带深部外围进行了成矿预测,并明确了下一步的找矿方向。  相似文献   

云南兰坪盆地古近系构造-层序岩相古地理特征分析   总被引：2，自引：0，他引：2  

范昱  陈洪德  侯中健  林良彪  罗洋  吕杜 《地层学杂志》2010,34(4)

构造—层序岩相古地理编图就是将岩相古地理的研究和编图与层序地层学的研究、盆地构造发展演化紧密结合,利用层序界面和其他关键界面为相对等时界面,按相关界面划分体系域,并以体系域为成图单元,采用体系域压缩法编制构造—层序岩相古地理图。以云南兰坪盆地古近系为例,进行构造—层序岩相古地理分析研究并编制构造—层序岩相古地理图,进而揭示该区古近纪构造运动对沉积特征与湖平面变化的关系,更进一步阐明该区盆地沉积充填的时空演化特征。  相似文献