Stages of development in the Polish Carpathian Foredeep basin

In southern Poland, Miocene deposits have been recognised both in the Outer Carpathians and the Carpathian Foredeep (PCF). In the Outer Carpathians, the Early Miocene deposits represent the youngest part of the flysch sequence, while in the Polish Carpathian Foredeep they are developed on the basement platform. The inner foredeep (beneath the Carpathians) is composed of Early to Middle Miocene deposits, while the outer foredeep is filled up with the Middle Miocene (Badenian and Sarmatian) strata, up to 3,000mthick. The Early Miocene strata are mainly terrestrial in origin, whereas the Badenian and Sarmatian strata are marine. The Carpathian Foredeep developed as a peripheral foreland basin related to the moving Carpathian front. The main episodes of intensive subsidence in the PCF correspond to the period of progressive emplacement of the Western Carpathians onto the foreland plate. The important driving force of tectonic subsidence was the emplacement of the nappe load related to subduction roll-back. During that time the loading effect of the thickening of the Carpathian accretionary wedge on the foreland plate increased and was followed by progressive acceleration of total subsidence. The mean rate of the Carpathian overthrusting, and north to north-east migration of the axes of depocentres reached 12 mm/yr at that time. During the Late Badenian-Sarmatian, the rate of advance of the Carpathian accretionary wedge was lower than that of pinch-out migration and, as a result, the basin widened. The Miocene convergence of the Carpathian wedge resulted in the migration of depocentres and onlap of successively younger deposits onto the foreland plate.     

内蒙古自治区突泉盆地TD-2井地层时代归属的探讨

正内蒙古自治区突泉盆地因在侏罗系中钻获轻质原油而备受地质学者们关注(李世臻等,2015),然而随着侏罗系油气的重大发现,使得盆地的性质、地层充填情况、基底特征等等一系列基础问题亟待解决。近年,随着锆石U-Pb同位素测年理论技术的不断发展,运用砂岩碎屑锆石LA-ICP-MS U-Pb年代学限定地层的沉积下限,进而分析其时代特征成为大多数地质学者识别、厘定"哑地层"的重要手     

Late Cretaceous to early Miocene deposits of the Carpathian foreland basin in southern Moravia

 The Late Cretaceous to Early Miocene strata of the Carpathian foreland basin in southern Moravia (Czech Republic) are represented by a variety of facies which reflects the evolution of the foreland depositional system. However, because of the intensive deformation and tectonic displacement and the lack of diagnostic fossils the stratigraphic correlation and paleogeographic interpretation of these strata are difficult and often controversial. In order to better correlate and to integrate them into a broader Alpine–Carpathian foreland depositional system, these discontinuous and fragmentary strata have been related to four major tectonic and depositional events: (a) formation of the Carpathian foreland basin in Late Cretaceous which followed the subduction of Tethys and subsequent deformation of the Inner Alps-Carpathians; (b) Middle to Late Eocene transgression over the European foreland and the Carpathian fold belt accompanied by deepening of the foreland basin and deposition of organic-rich Menilitic Formation; (c) Late Oligocene to Early Miocene (Egerian) uplifting and deformation of inner zones of the Carpathian flysch belt and deposition of Krosno-type flysch in the foreland basin; and (d) Early Miocene (Eggenburgian) marine transgression and formation of late orogenic and postorogenic molasse-type foreland basin in the foreland. These four principal events and corresponding depositional sequences are recognized throughout the region and can be used as a framework for regional correlation within the Alpine–Carpathian foreland basin. Received: 18 August 1998 / Accepted: 9 June 1999     

鄂尔多斯盆地西南部巨厚黄土塬区非纵地震资料处理技术

鄂尔多斯盆地西南部地表为巨厚黄土塬区,地表结构复杂,低降速带厚度变化快,沟中弯线受地形条件限制,测线成网困难,直测线采集资料信噪比和分辫率都较低,难以满足目前岩性勘探的需求。针对这种情况,在经过理论论证和生产试验后,研发了一套针对黄土塬地区的非纵地震勘探技术,这种技术兼顾吸收了黄土塬沟中弯线、黄土塬多线及三维地震勘探技术的优点,不仅避开了黄土塬近炮点强能量干扰,而且还展宽了叠加道集方位角。针对非纵地震资料特点,在保真保幅处理理念指导下,通过非纵资料处理技术攻关,提出了针对非纵资料的三维静校正技术、创新性应用三维噪声压制模块压制非纵测线相干噪声、改进了基于VSP测井合成记录的井控处理理念,形成了一套巨厚黄土塬区低信噪比非纵地震资料处理技术序列。     

西藏东部昌都—类乌齐三叠纪克拉通盆地层序地层及其对比

昌都-类乌齐地区的三叠系发育较好,尤其是上三叠统建组剖面多。以露头剖面为基础,在晚三叠世地层中可识别出4个三级层序界面,其中1个Ⅰ类界面与3个Ⅱ类界面;划分出4个三级层序,分别为1个Ⅰ类层序和3个Ⅱ类层序。笔者研究认为,该区克拉通盆地三级层序的类型、结构与数量等方面具有可对比性。     

Fracture and stress orientation from borehole image logs: A case study from Cambay basin,India

The Deccan trap basalt, laid down by multiple lava flows during upper Cretaceous to Paleocene times forms the basement of current study in Cambay basin. As such, there is great interest and value in fracture detection and evaluation of fractured basement reservoirs in the Cambay basin. The procedure for identification and evaluation of natural as well as induced fractures in basaltic basement of the Cambay basin is presented in this work. In this study formation micro-imager (FMI) and extended range micro-imager (XRMI) log data for fracture identification is used. The Deccan trap basaltic basement of the study area, comprising five wells in the Tarapur-Cambay block, has potential for holding commercial hydrocarbon due to the presence of fractures and weathered basement. Both image logs (FMI, XRMI) identify three types of fracture including open (conductive), partially open and closed (resistive) fractures, of which open and partially open fractures are important for hydrocarbon accumulation. Fracture dip ranges from 10° to 80°. Image logs have also identified washout, breakout and drilling-induced fracture zones. The strike direction of the open natural fractures for four wells varies from N60°E to N30°E whereas the strike direction of most natural fracture in the fifth well is oriented towards N20°W. The orientations of drilling-induced fractures and breakouts may be interpreted for the in-situ stress direction over the logged interval. Drilling-induced tensile fractures, identified over the depth interval of 1969–1972 m, and borehole breakouts over the interval of 1953–1955 m in one well, suggest an orientation of maximum in-situ horizontal compressive stress (S_H) lies in the north-south direction. The azimuths of open natural fractures in the same well vary from north-south to N30°E. It is expected that the direction of fluid flow will be controlled by open natural fractures and therefore would be in a direction parallel to the S_H direction, which is orthogonal to the minimum horizontal stress (S_h) direction. The orientations observed are consistent with the present day S_H direction in the study area of Cambay basin.     

准噶尔盆地中部2区块高分辨层序地层研究

根据沉积相序变化、准层序叠加样式、测井曲线特征,运用关键坡折带知识,通过伴生的低水位域底界面的识别及附近的超失、削截特征分析,仔细追踪和查明了准噶尔盆地腹部地区中部2区块9条关键界面.进行了侏罗系的高分辨层序地层的划分。研究表明C1井区J_1b_2-J_2t沉积时期可划分出8个三级层序,均具有完整的三分结构:LST、TST和HST;共划分出27个体系域,共识别出准层序组56个,准层序118个。单个层序的厚度105.6～176.8 m,平均140.7 m;单个准层序组平均24.9 m;单个准层序平均11.8 m。     

The Carpathian Mountain range and the enclosed interior

The baffling duality of the Carpathian Mountain Range and the Basin it surrounds is briefly discussed. The various attempts at solving the nature of this duality, including plate tectonics with its micro-plates are mentioned. The component ranges of the Carpathians and the structural belts are given, followed by the discussion of the Carpathian Basin System, the Interior, consisting of the Great Hungarian Plain, Transdanubia, the two groups of Central Mountains, also the Apuseni (Bihar) Mountains and the Banat Contact Belt. Economic ore deposits are featured in the relevant sections.     

Palaeogeographic and burial controls on anhydrite genesis: the Badenian basin in the Carpathian Foredeep (southern Poland, western Ukraine)

The Badenian (Middle Miocene) Ca-sulphate deposits of the fore-Carpathian basin – including the shelf and adjacent salt depocentre – have undergone varying degrees of diagenetic change: they are preserved mainly as primary gypsum in the peripheral part of the platform, whereas toward the centre of the basin, where great subsidence occurred during the Miocene, they have been totally transformed into anhydrite. The facies variation and sequence of Badenian anhydrites reflect different genetic patterns of two members of the Ca-sulphate formation. In the lower member (restricted to the platform), anhydrite formed mainly by synsedimentary anhydritization (via nodule formation), whereas in the upper member (distributed throughout the platform and depocentre) the various gypsum/anhydrite lithofacies display a continuum of distinctive anhydrite type-fabrics. These fabrics are based on petrographic features and show from the centre to the margin: (1) syndepositional, interstitial growth of displacive anhydrite; (2) early diagenetic, displacive to replacive (by replacement of former gypsum) anhydrite formation near the depositional surface; (3) early diagenetic, displacive to replacive anhydrite formation during shallow burial; and (4) late-diagenetic (and only partial) replacement of gypsum at deeper burial. The cross-shelf lateral relations of anhydrite lithofacies and fabrics suggest that the diagenesis developed as a diachronous process. These fabrics of the upper member reflect both palaeogeographic (linked to different parts of the basin) and burial controls. Anhydrite growth started very early in the basin centre, presumably related to high-salinity pore fluids; anhydritization prograded updip toward the shelf (landward in a generalized cross-section through the basin). The intensity of gypsum replacement by anhydrite was progressively attenuated landward by a decrease in the salinity of the pore fluids. In each part of the basin, the anhydrite fabric was also controlled by the texture and degree of lithification of the fine-grained primary gypsum lithofacies. Recrystallization of these anhydrite fabrics during late diagenesis, linked to deeper burial conditions, is insignificant, allowing reconstruction of the original anhydritization pattern.     

Paleogeographic provinces of the periglacial loess association in the middle Volga basin

Specific features of the formation and distribution of periglacial loess association in the Volga region are discussed. Based on generalization of the results of the systematic paleogeographic analysis, the paper presents a comprehensive characteristic of the polygenetic and polychronous loess rocks. The results show regional specifics in the structure and composition of loess rock horizons confined to different-aged paleogeographic zones of the Russian Plain. Provincial discrepancies in the distribution and thickness of loess rocks are demonstrated in the summary map. Comparison of the complex characteristics of the loess rocks provides insight into the general trend of spatiotemporal variability of their structure and composition. Latitudinal zonation is manifested in the thickening of loess rock sequences along the distal direction of the paleoglacial zone (on the average, from 1.3 m to 5–10 m or more) and is usually accompanied by increase in contents of the silty material and carbonates and degree of sagging. Moreover, the stratigraphic structure of sections becomes more complicated with increase of the age interval of loess–soil series. The spatiotemporal trends, which are revealed in the development and periodicity of loess formation, have a great significance for the reconstruction of paleogeographic events in the Neopleistocene.     

松科二井东孔营城组火山岩测井响应特征及岩性评价

为开展松辽盆地深部长期观测、流体实验和探索白垩纪火山事件,利用松科二井东孔丰富、齐全的测井资料,对营城组火山岩岩性进行评价。通过测井响应特征分析发现,松科二井东孔营城组凝灰岩具有最强的放射性和导电性,高孔隙度的集块熔岩密度为低值,流纹岩表现出高密度和低导电性。利用测井交会图和成像识别模式,识别出松科二井东孔营城组火山岩以流纹岩、凝灰熔岩和集块熔岩为主,少量的凝灰岩。结合凝灰岩处测井曲线变化特点,证明了火山喷发间断的存在。流纹岩具有高碱、高Si、低Fe和低黏土矿物特征。T_2谱分析认为流纹岩有利于后期深部长期观测和流体实验的开展。研究成果对松科二井东孔后续火石岭组火成岩及整个松辽盆地火山岩研究具有一定的参考价值。     

A luminescence‐based chronology for the Harletz loess sequence,Bulgaria

The Harletz loess‐palaeosol sequence is located in northwestern Bulgaria and represents an important link between well‐studied loess sequences in eastern Romania and further sites to the west of the Carpathians (e.g. Serbia and Hungary). The aim of this study was to establish a chronostratigraphy of the deposits, using various methods of luminescence dating, together with basic stratigraphical field observations as well as magnetic properties. Luminescence dating was carried out using the quartz fine grain fraction and a SAR protocol, and the feldspar coarse grain fraction, applying the MET‐pIRIR protocol. Due to underestimation of the quartz fine grain fraction in the lower parts of the sequence, the resulting chronology is mainly based on the feldspar ages, which are derived from the stimulation temperature at 150 °C. A comparison with nearby sequences from Serbia, Hungary and Romania, and interpretations obtained through the stratigraphical and sedimentological signature of the sequence, supports the established chronology. Our data suggest that the prominent palaeosol (soil complex) in the upper quarter of the sequence was formed during MIS 5. It would follow that large parts of the Last Glacial loess overlying this palaeosol were probably eroded, and that the thick loess accumulation underlying this soil complex can be allocated to the penultimate glacial (MIS 6). A prominent MIS 6 tephra, which has been reported from other sequences in the area, is also present at Harletz.     

豫西南晚白垩世地层时代研究的进展

近年来，豫西南一带红层时代的研究，获得了包括恐龙蛋、恐龙与轮藻、介形类、孢粉及同位素年龄等方面的重要材料，为区内划分的晚白垩世高沟组、马家村组、寺沟组地层时代，提供了新的和可靠的证据，排除了认为属于早白垩世、白垩纪或其他意见的可能。     

断陷湖盆层序地层单元与油气的关系

陆相湖盆层序地层单元与油气存在密切关系，目前对两关系的研究还远远不够，因此深入研究层序地层界面及所夹持的地层，对分析油气形成、聚集过程具特殊的意义．针对层序地层单元与油气的关系，通过实例分析，总结了体系域中4种成藏模式和主要层序地层界面(初次湖泛面，最大湖泛面)对油气成藏的影响和控制．同时进行了高精度层序地层学研究，以准层序单元为单位，结合实例对准层序与油气的关系进行了探讨，并进行了单井及连井剖面分析，把层序地层单元研究与沉积相有机地结合起来，取得了很好的效果．     

黄县早第三纪断陷盆地充填特征及层序划分

黄县早第三纪断陷盆地充填沉积序列共划分出三个层序(三级层序),层序Ⅰ不完整,层序Ⅰ和层序Ⅱ皆由低位体系域、扩张体系域和萎缩体系域三个基本单位构成。层序界面主要有区域构造运动界面和盆地构造应力转换面一体系域转换界面两种类型。聚煤作用、油气聚集主要发生在盆地低水位至扩张期,低水位和扩张体系域含有主要的煤层和油气母岩(生油岩)。     

A simple approach to define Holocene sequence stratigraphy using borehole and cone penetration test data

Cone penetration testing has been widely used since the 1950s for determining the subsurface geotechnical conditions of unconsolidated sediments. This paper highlights the potential value of cone penetration testing as an aid to define the stratigraphic structure of Holocene sedimentary deposits. By calibrating cone penetration test logs with adjacent borehole logs and by utilizing all the available information produced during geotechnical surveying, stratigraphic models that accurately describe the vertical and lateral boundaries, as well as the stacking pattern, of Late Quaternary systems can be constructed. The widespread application and technical simplicity of cone penetration testing, combined with simple data interpretation via correlation with adjacent borehole logs, yield a useful and inexpensive tool for sedimentological investigations. This methodology is illustrated using data from 36 cone penetration tests and 11 boreholes on the Holocene deltaic plain of the Aliakmon River, Greece. Sedimentological and stratigraphic information from core log correlations, the spatial distribution of cone penetration test parameters, sediment grain size and per cent concentration of organic matter are utilized. The results suggest, that in sequence stratigraphic terms, the delta is divided into a lowstand systems tract composed by fluvial gravels and sands (U0) of Late Pleistocene age, as well as from red oxidized clays, and a transgressive systems tract represented by fluvial channel sands (U1), overlain by a thin transgressive sand sheet of coastal origin (U2), characterized by fining upward trends. The highstand systems tract is constituted by a variety of stratigraphic units (U3 to U7) and depositional environments, characterized by coarsening upward sequences, representing both aggradational and progradational facies, and dominated by the presence of three prograding wedges. Detailed definition of the thickness, vertical boundaries and stacking pattern of the resolved stratigraphic units, presented as a two‐dimensional stratigraphic model, demonstrates the applicability of the proposed method.     

A palaeomagnetic and mineral magnetic study of the loess sequence at Liujiapo,Xian, China

Employing an average vertical sampling interval of 20 cm, oriented samples were collected from 26 m of the loess section at Liujiapo, near Xian, China in order to refine the existing magnetostratigraphic record. Palaeomagnetic results reveal two short reversed-polarity subzones within a profile of predominantly normally magnetised sediments, an interpretation that is at variance with previous results from this section and from other studies of Chinese loess. Investigation of sediment mineral-magnetic properties indicates a close correspondence between down-section variations in intensity of magnetisation, susceptibility and saturation isothermal Journal of Quaternary Science remanence (SIRM), and lithology. The ratios IRM_-100mT/SIRM and SIRM/ susceptibility appear to be particularly sensitive indicators of the degree of soil development and hence of palaeoclimate.     

藏北羌塘盆地最大规模沥青脉的发现

羌塘盆地有着与中东特提斯油气集聚区可类比的油气地质条件,1994-1997年间,中石油总公司在其中开展了大规模的综合性油气地质调查工作,取得了丰硕成果,进一步证实其为一个重要的含油气盆地.     

焉耆盆地中生界层序地层和沉积体系分析

利用层序地层学原理和方法，建立了焉耆盆地中生界层序地层格架，将其划分为4个层序，继而分析了各个层序的地层特征、层序演化及各个体系域的沉积体系展布。研究表明，焉耆盆地中生代存在南北两大物源体系，盆地总体上以河流－湖泊沼泽相的浅水沉积为主，湖泊水体深度不大且分布范围有限；层序Ⅲ的水进体系域是湖盆发育的鼎盛时期，构成了本区良好的盖层；通过层序构成分析，探讨了隐蔽圈闭发育的有利层位及区带。