Facies, cycles, and controls on the evolution of a keep-up carbonate platform (Kimmeridgian, Swiss Jura)

During the Late Jurassic, accelerated ocean-floor spreading and associated sea-level rise were responsible for a worldwide transgression, which reached its maximum in the Late Kimmeridgian. In many Western European basins, this major sea-level rise led to the formation of marly and condensed sections. In the Swiss Jura, however, a shallow carbonate platform kept growing and only subtle changes in the stratigraphic record suggest an increasingly open-marine influence. Field observations and thin-section analyses reveal that the central Swiss Jura was at that time occupied by tidal flats and by more or less open marine lagoons where shoals and bioherms developed. The evolution through time of sedimentary facies and bed thicknesses permits the definition of small-, medium-, and large-scale depositional sequences. The diagnostic features of these sequences are independent of scale and seem largely controlled by the Kimmeridgian second-order transgression. A high-resolution sequence-stratigraphic correlation with biostratigraphically well-dated hemipelagic and pelagic sections in the Vocontian Basin in France reveals that: (i) The most important increase in accommodation recorded in the Kimmeridgian of the central Swiss Jura occurs in the Eudoxus ammonite zone (Late Kimmeridgian) and corresponds to the second-order maximum flooding recognized in many sedimentary basins. (ii) The small- and medium-scale sequences have time durations corresponding to the first and second orbital eccentricity cycle (i.e. 100 and 400 ka, respectively), suggesting that sedimentation on the platform and in the basin was at least partly controlled by cyclic environmental changes induced by insolation variations in the Milankovitch frequency band. The comparison of the high-resolution temporal framework defined in the Swiss Jura and Vocontian Basin with the sequence-stratigraphic interpretation realized in other Western European basins shows that the large-scale sequence boundaries defined in the Kimmeridgian of the Swiss Jura appear in comparable biostratigraphic positions in most Western European basins. Discrepancies that occur are probably because of local or regional tectonics.     

The Devonian–Lower Carboniferous succession in Northwest Peninsular Malaysia

A new stratigraphic nomenclature is proposed for the approximately 600 m thick, mainly clastic transitional sequence between the underlying Mempelam Limestone and overlying Kubang Pasu/Singa Formation in northwest Peninsular Malaysia. This sequence represents shallow marine deposits of the continental margin of the Sibumasu Terrane during the Middle Palaeozoic (Devonian–Carboniferous). It is separated into several formations. The Timah Tasoh Formation is an approximately 76 m sequence consisting of 40 m of laminated tentaculitid shales at the base, containing Monograptus yukonensis Jackson and Lenz and Nowakia (Turkestanella) acuaria Alberti, giving an Early Devonian (Pragian–Emsian) age, and about 36 m of rhythmically interbedded, light coloured argillo-arenites. The Chepor Formation is about 90 m thick and consists mainly of thick red mudstone interbedded with sandstone beds, of Middle to Late Devonian age. A new limestone unit is recognized and named the Sanai Limestone, which contains conodonts of Famennian age. The Binjal Formation consists of red and white mudstone interbedded with sandstone beds showing Bouma sequences. The Telaga Jatoh Formation is 9 m thick and consists mainly of radiolarian chert. The Wang Kelian Formation is composed of thick red mudstone beds interbedded with silty sandstone, and contain fossils indicative of an Early Carboniferous (Visean) age. The succession was deposited on the outer shelf, with depositional environments vertically fluctuating from prodelta to basinal marine. The Devonian–Carboniferous boundary is exposed at Hutan Aji and Kampung Guar Jentik, and indicates a major regressive event during the latest Devonian.     

Sequence stratigraphy of the Upper Oligocene–Lower Miocene of eastern Jylland, Denmark: role of structural relief and variable sediment supply in controlling sequence development

The Upper Oligocene–Lower Miocene succession in eastern Jylland can be subdivided into three sequences (A–C from older to younger) deposited on and around the Ringkøbing-Fyn High. The development of the sequences reflects a complex interaction between eustatic sea-level changes, physiography and variable sediment supply. Superimposed on this, frequent storms promoted longshore sediment transport and the development of spit systems adjacent to structural highs. As a consequence, sequence boundaries and flooding surfaces are not always expressed as portrayed in conventional sequence models; sequence boundaries or flooding surfaces may only be marked by subtle changes in depositional environment that can only be revealed by careful integration of sedimentological observations with palynological data. The influence of the topography resulted in the development of brackish water basins that were sufficiently large to permit the deposition of hummocky cross-stratified sands with muds. These deposits are overlain by clean hummocky and swaley cross-stratified sands that were deposited in a fully marine, high-energy environment. This evolution from mud-rich, storm-influenced sediments to sand-dominated shoreface sediments resulted from a rise in sea level and was not the result of shoreface progradation and downstepping during a sea level fall. In addition to the topographic control on sequence development, sediment supply to the study area changed significantly during the deposition of the three sequences. Initially the basin was sediment-starved, favouring the formation of glaucony-rich sediments. The sediment input gradually increased and the influence of structural highs and lows became less significant with time. Consequently, both sequence boundaries and flooding surfaces are characterized by more conventional features in the younger part of the succession, where a basinward displacement of the shoreline resulted in thick lowstand delta deposits.     

Sequence-Stratigraphic Framework from the Carboniferous to the Permian Chuanshanian Epoch in Dianqiangui Basin and Its Adjacent Areas, Southwest China

INTRODUCTION Alotofprogresshasbeenmadeinthestudyof Carboniferoussedimentologyandstratigraphyinthe Dianqianguibasinanditsadjacentareas,whichin cludethecomprehensivesummariesonchronostratigraphyandbiostratigraphybyJinetal.(2000)and Kuangetal.(1999);theoverallandsystematicsum mariesonCarboniferouslithostratigraphybyDong(1997),Yin(1997)andZhao(1996);thecompre hensivestudyonCarboniferoussedimentaryfacies andpaleogeographybyChenetal.(1994)andFeng etal.(1998)etc..AsshowninFig.1,theDian qiang…     

四川盆地非海相三叠系-侏罗系界线研究

对四川盆地几条典型的三叠系一侏罗系界线剖面的生物标志、岩性特点、沉积层序及古气候变化进行综合研究，发现Coniopteris属的始现为三叠系一侏罗系界线的古植物标志、双壳类Margaritifern（Qiyangia）的首现和孢粉中孢子与花粉百分含量在界线上、下的显著变化也可作为三叠系一侏罗系界线的生物标志，三叠系一侏罗系界线之上的岩石组合大致可分为4种基本类型：砾岩型、石英砂岩夹砾岩型、石英砂岩型和粉砂质泥岩型。建议重庆合川炭坝剖面及宣汉七里峡剖面分别为四川盆地非海相三叠系一侏罗系界线层型剖面和副层型剖面。     

箕状断陷盆地缓坡带层序格架特征与演化--以济阳坳陷为例

依据缓坡带对层序类型、地层结构特征的控制及地貌特征、成因将济阳坳陷缓坡带分为单断-沉积坡折型、单断-斜坡型和双断-构造坡折型三种类型.三种缓坡类型构造-沉积演化背景不同,形成了不同的层序格架特征.济阳断陷盆地的构造演化史决定了较完整的缓坡带层序演化由双断-构造坡折型向单断-沉积坡折型再向单断-斜坡型演化.     

高频电磁测深在地下热水勘探中的应用

高频电磁测深法是一种利用天然高频电磁场作为场源的电磁勘探方法,具有高分辨率和相对直流电法较深的勘探深度的特点,特别适合中浅层地热和地下水勘探。本文介绍了一个应用高频电磁测深评价地下热水资源的一个成功实例。野外数据采集采用了高频电磁测深系统MT-U5A,采用远参考技术,以保证数据采集质量。高频电磁测深资料二维反演成像处理结果较好地描述了地下热水的空间分布范围,为查明该区的地下热水的来源提供了较有利的证据。     

The application of the high-frequency electromagnetic sounding method in the exploration of underground thermal water

High-frequency electromagnetic sounding is an electromagnetic exploration method using the natural high-frequency electromagnetic field as a field source. It has higher resolution and greater depth penetration than the direct current method and is especially fit for geothermal energy exploration and low- and mid-level groundwater detection. We introduce a successful application of high-frequency electromagnetic sounding for evaluating geothermal water resources. The high frequency electromagnetic system （MT-USA with a frequency range from 10 KHz to 1 Hz） is first applied to sample field data from China. A remote reference station is used to assure sampled data quality. We then perform 2D inversion image processing with the electrical method data. The results basically indicate the spatial distribution of underground geothermal water and provide favorable clues to finding the sources of the subsurface geothermal water in this area.     

To evaluation of new methodical approaches in the sequence stratigraphy analysis

Despite great practical achievements, sequence stratigraphy failed to elaborate until now the reliable technique for establishing relative sea-level fluctuations (RSLF). The method proposed recently by Yu.A. Volozh with colleagues for determining the RSLF represents one of interesting but unconvincing attempts in this respect. Use of their method for fundamental and practical purposes requires prudence because of potential errors.     

大面阵CCD影像多通道不一致性消除算法

大面阵CCD多通道影像转移过程中,由于通道硬件的偏置和增益的不一致,将造成各通道影像的亮度和反差的微小差异,以致重建后的大面阵CCD影像出现条带效应。提出基于随机序列分析的模拟运动影像拼接算法,并将这种方法与基于影像直方图均衡化和影像直方图规定化的影像拼接算法进行比较。实验证明,基于随机序列分析的模拟运动影像拼接算法不仅能保持拼接后的影像整体一致性,而且能较好的消除拼接缝。该算法已经应用于我国第一台大面阵彩色CCD数字航测相机的影像预处理。