Defining the concept of stratigraphic grade and applying it to stratal (reservoir) architecture and evolution of the slope-to-basin profile: An outcrop perspective   总被引：1，自引：0，他引：1  

David R. Pyles  James P.M. SyvitskiRoger M. Slatt 《Marine and Petroleum Geology》2011,28(3):675-697

Stratigraphic grade is the similarity of the morphology of successive slope-to-basin profiles in a genetically related depositional system. In this article we use data collected from regional cross-sections of six depositional systems, stratal architecture derived from outcrops of the Lewis Shale (Wyoming, USA), and the Ross Sandstone (Ireland), and supplementary outcrop and subsurface data from other depositional systems to determine how stratigraphic grade relates to stratal (reservoir) architecture in deepwater systems.Four methods are developed that collectively define stratigraphic grade: (1) regional stacking patterns of fourth-order stratigraphic surfaces, (2) the relationship between the trajectory of the shelf edge (T_se) and the trajectory of the depocenter (T_d) for fourth-order stratigraphic units, (3) morphology of the slope-to-basin profiles of fourth-order stratigraphic surfaces, and (4) the similarity of the morphologies of slope-to-basin profiles of fourth-order surfaces in a system (σ_s, σ_r). Several characteristics of stratigraphic (reservoir) architecture of fourth-order stratigraphic cycles are related to stratigraphic grade: (1) longitudinal distribution of sandstone in fourth-order cycles, (2) location of maximum sandstone relative to the depocenter of fourth-order cycles, (3) lengths of fourth-order submarine fans, and (4) longitudinal and vertical distribution of architectural elements. Stratigraphic grade is thus a predictor of reservoir architecture and can thereby be used to reduce the uncertainty in the interpretation of subsurface data.The concept of stratigraphic grade is useful in understanding the stratigraphic evolution of deepwater systems. Most deepwater systems analyzed in this study initiated as out-of-grade and temporally evolved to graded systems over a time span of millions of years. Systems rarely evolve from graded to out-of-grade. First-order controls on stratigraphic grade are determined to be angle of slope, tectonically forced changes in angle of slope during deposition, and sediment supply.  相似文献   

Late Cenomanian–Early Turonian ammonites of the southern Tethys margin from Morocco to Oman: Biostratigraphy,paleobiogeography and morphology     

《Cretaceous Research》2013

The Cenomanian–Turonian ammonite biostratigraphical framework for the southern Tethys margin (North Africa, Middle East and the Arabian Peninsula) is becoming better understood. A first attempt at a synthetic range chart is presented, with 85 taxa and precise correlations for ammonites along a west–east transect from Morocco to Oman, inclusive of the Trans-Saharan Seaway as far south as northern Nigeria. On the basis of a critical review of ammonite taxonomy, 13 bioevents can be identified in the interval from the Late Cenomanian to the Early Turonian (c. 3.5 myr) with each bioevent corresponding to a time interval of approximately 270,000 years, on average. They are consistent throughout several regions along the southern Tethys margin, though some gaps remain, at least at the stage boundary. These bioevents are correlated with the zonation defined for the stratotype (GSSP) of the base of the Turonian in the Western Interior (USA). The paleobiogeographic distribution of ammonites reveals some endemism but the predominant picture is that of a homogeneous fauna throughout the area, even though distinct Boreal and Western Tethys (Atlantic domain) marine influences are evident. An interpretation of the evolution of conch morphology and ornamentation through the zones of the Late Cenomanian–Early Turonian is proposed.  相似文献   

Morpho-sedimentary evolution of the lower Moulouya (North Eastern Morocco) during middle and upper Holocene. Seismicity and neotectonic effects     

《Geodinamica Acta》2013,26(3):205-217

Analysis of sediments and morpho-structural elements of the last 25 km of the lower Moulouya valley has shown that this river evolved during the middle and upper Holocene in a tectonic context of uplift, at the South-Eastern end of the Kebdana Mountains. This geodynamic context limited the sedimentation and inhibited the formation of a delta on the Mediterranean shore. A brief sedimentary episode allowed about 10 m of sediments to be deposited, forming a well-marked alluvial terrace. The sedimentation appeared before 3,750 years cal BC in connection with the Holocene sea transgression (“Mellahian” period) and a probably more humid period. It developed at an average rate of 0.6 mm.a–1, five kilometres from the shoreline, before stopping just after 395 years cal BC, at the same time as the post- Mellahian regression. The sediments show evidence of syn- and post-sedimentary seismic activity (seismites, diaclases, faults). They also show some traces of the “Mellahian” transgression (beds containing halite and gypsum) which indicate an average rise of 2.0 mm.a–1 since about 3,700 years cal BC, 22 km from the Moulouya mouth. The sediment composition indicates a subarid climate during the Holocene, but does not enable possible climatic variations to be detected.  相似文献   

甘肃宝积山盆地上三叠统舌叶属化石形态模型建立初探          下载免费PDF全文

万震  赵海钧  刘洁  马福军 《甘肃地质》2013,22(2):33-37

本文试用数码相机,图形处理和数据分析软件相结合的方法,对采集于甘肃省白银市宝积山盆地上三叠统南营儿组舌叶属化石叶片进行数字化,获得其叶形的主要基本参数数据,使用数据分析软件建立舌叶属叶片上、下边缘函数曲线模型,利用模型对舌叶属化石叶片特征进行讨论,进而对保存不完整的叶片原形进行恢复,结果表明重建的化石形态与原叶片宏观特征吻合程度很好,建立叶片数学模型方法恢复不完整保存舌叶整体形态具有可行性。  相似文献   

Automated delineation and characterization of drumlins using a localized contour tree approach     

《International Journal of Applied Earth Observation and Geoinformation》2017

Drumlins are ubiquitous landforms in previously glaciated regions, formed through a series of complex subglacial processes operating underneath the paleo-ice sheets. Accurate delineation and characterization of drumlins are essential for understanding the formation mechanism of drumlins as well as the flow behaviors and basal conditions of paleo-ice sheets. Automated mapping of drumlins is particularly important for examining the distribution patterns of drumlins across large spatial scales. This paper presents an automated vector-based approach to mapping drumlins from high-resolution light detection and ranging (LiDAR) data. The rationale is to extract a set of concentric contours by building localized contour trees and establishing topological relationships. This automated method can overcome the shortcomings of previously manual and automated methods for mapping drumlins, for instance, the azimuthal biases during the generation of shaded relief images. A case study was carried out over a portion of the New York Drumlin Field. Overall 1181 drumlins were identified from the LiDAR-derived DEM across the study region, which had been underestimated in previous literature. The delineation results were visually and statistically compared to the manual digitization results. The morphology of drumlins was characterized by quantifying the length, width, elongation ratio, height, area, and volume. Statistical and spatial analyses were conducted to examine the distribution pattern and spatial variability of drumlin size and form. The drumlins and the morphologic characteristics exhibit significant spatial clustering rather than randomly distributed patterns. The form of drumlins varies from ovoid to spindle shapes towards the downstream direction of paleo ice flows, along with the decrease in width, area, and volume. This observation is in line with previous studies, which may be explained by the variations in sediment thickness and/or the velocity increases of ice flows towards ice front.  相似文献   

黄海远东拟沙丁鱼种群鉴别的研究     

韦晟  陈毓桢  周彬彬  孙建明 《海洋科学》1989,13(4):55-60

本文根据黄海远东拟沙丁鱼[Sardinops melanostistus (Temminck et schlegel)]的生态学特征、生物学特性以及形态学特征综合分析比较结果,证明了黄海海州湾渔场和石岛渔场的鱼群样品非常相似,认为这两个渔场的远东拟沙丁鱼是同一个群体,均属九州群系。  相似文献   

Morphology, Distribution, Life Habits and Phylogenetic Affinities of the Recent Brachiopod Gwynia capsula (Jeffreys)     

A. Logan    D. I. MacKinnon  J. E. Phorson 《Marine Ecology》1997,18(3):239-252

  相似文献   

Landscape evolution and glaciation of the Rwenzori Mountains, Uganda: Insights from numerical modeling     

Georg Kaufmann  Douchko Romanov 《Geomorphology》2012,138(1):263-275

The Rwenzori Mountains are a high alpine mountain chain, about 40 × 80 km in size, just north of the equator in the western branch of the East African Rift System in Africa. The central part of the mountain chain is located in Uganda, and the highest peak, the Margherita Peak with 5119 m, lies on the border to the Democratic Republic of Congo. Topography is very pronounced, with steeply incised valleys and clear glacial landforms in the upper part of the mountain chain. The Rwenzori Mountains are an unusually high mountain chain located in the extensional setting of the East African Rift System, and the large elevation poses a challenging problem for geodynamists to explain.We have used the landscape evolution model ULTIMA THULE, which combines hillslope diffusion, fluvial erosion, and glacial abrasion and is driven by a climate driver, simulating the variations in temperature, precipitation, and relief over several glacial cycles. With a simulation time of 800 ka, we test the hypothesis of climate-tectonic interactions on the uplift of the Rwenzori Mountains.Our results show that a moderate cooling of around 6° causes widespread glaciation of the high mountain regions as observed during the peak glacial phases, and that morphological processes degrading the landscape allow for a tectonic uplift rate of around 0.5 mm a^− 1.  相似文献   

CHARACTERISTICS OF SEDIMENT TRANSPORT AND CHANNEL FORMATION BY FLOODS AT HYPERCONCENTRATIONS OF SEDIMENT IN THE YELLOW RIVER     

QI Pu  ZHAO Yean Engineer  Institute of Hydraulic Research  Yellow River Conservancy Commission Engineer  Institute of Hydraulic Research  Yellow River Conservancy Commission 《国际泥沙研究》1993,(1)

1. INTRODUCTIONThe Yellow River is a heavily sediment--laden river. Floods at Hyperconcentrationso f sediment (hereinafter simply referred to as hyperconcentrated flood) frequently occurring in the main river and its tributaries possess different characteristics of sedimenttransport. Sometimes they cause severe deposition whereas at other times they are capable of carrying substantial amount of sediment over long distances. The study on the lawof sediment transport is of significance to …  相似文献   

BED MORPHOLOGY OF THE KOSI RIVER, GANGETIC PLAINS     

Prabhata K. SWAMEE  Barham PARKASH  Harbhajan SINGH Prof.  Civil Engrg. Dept.  Univ. of Roorkee  Roorkee  India  Prof.  Earth Sciences Dept.  Univ. of Roorkee  Roorkee 《国际泥沙研究》2002,17(1)

  相似文献