The sedimentation model of the Tuapse Trough (Black Sea)

Based on the new 2D and 3D seismic data from the Tuapse Trough (Black Sea), the principle peculiarities of sedimentation have been studied in detail. A sedimentation model of the focused Maikop and Karagan-Chokrak intervals of the geological section has been suggested. A system of fan complexes referred to Maikop age has been found.     

Quaternary stratigraphy and palaeogeography on the Black Sea coast of Western Caucasus

On the basis of new data a revised stratigraphic scheme for the Anthropogene of the Black Sea region is suggested. Radiological dates are given for the absolute age of the three Black Sea transgressions with a Karangat-type fauna and two Holocene transgressions. The structure of overdeepened estuarine parts of river valleys and the stratigraphy of slope and cave deposits are discussed.     

Modern erosion and sedimentation processes in the deep-water part of the Tuapse Trough based on the data of 3D seismic survey

On the basis of new 2D/3D seismic data, the modern tectonic, erosion, and sedimentation processes have been studied in detail in the Tuapse Trough of the Black Sea. The principal processes identified are growth of anticline folds, erosion of submarine ridges, and formation of submarine channels and modern small basins. It has been shown that erosion of submarine ridges took place throughout the entire evolution of their growth.     

Conditions of oil source potential formation in the Eocene deposits in the basins of the Crimea and Caucasus regions

The article is dedicated to multidisciplinary studies of organic matter (OM) in Eocene deposits. In the Ciscaucasia region, the mean content of organic carbon in the Kumian deposits is high. A decrease in quality is partly related to the approaching of the displacement source. In the investigated regions of Ciscaucasia and Crimea, hydrogen sulfide contamination of the water column in Eocene basins did not exist. Eocene carbon deposits are characterized by increased and high OM oil source potential. A sharp increase in primary biological production is likely to be related to endogenous processes.     

川东北何家营地区三维构造模型：来自高精度线束三维资料的约束

川东北地区方斗山构造带发育典型的多重滑脱构造,中生代以来受大巴山南北向挤压与雪峰山北西向挤压叠加改造。其构造模型在区域性滑脱层的分布、不同构造变形层构造样式的厘定以及不同构造变形层在空间上耦合特征等方面存在争议,因此定量分析不同变形层构造样式的差异与空间组合特征成为研究分层变形成因机制的关键。本文应用数字高程、浅表地质信息与线束三维地震数据等资料,开展方斗山北段何家营地区地层与断裂构造解析,建立了何家营地区的三维构造模型,讨论方斗山北段多重滑脱层体系下,垂向上不同构造变形层的差异变形特征及其控制因素。研究表明：何家营地区沉积盖层中存在中-下寒武统膏盐层、下志留统泥岩层、下三叠统嘉陵江组膏盐层等3套区域性滑脱层以及二叠系煤层局部滑脱层。区域性滑脱层控制了褶皱—冲断构造的变形样式,构造在垂向解耦,形成基底、深部、中部与浅部等4套变形层。基底变形层发育指向北西的构造楔;深部变形层夹持于寒武系与志留系滑脱层之间,发育双重构造,形成低幅度背斜;中部变形层为志留系与嘉陵江组之间的高角度冲断构造,二叠系煤层作为局部滑脱层,发育顺层剪切;浅部变形层,以嘉陵江组盐滑脱褶皱为主。不同变形层的垂向叠置,共同形成了现今的高陡背斜。不同构造变形层地层能干性组合与缩短量的差异决定了构造样式的差异。软弱层传递位移,中寒武统膏盐层、志留系页岩与下三叠统膏盐层,缩短量最大,变形最强,是控制区域变形的主要滑脱层。何家营地区发育倾向南东的基底断层,不同变形层的主干断层与褶皱轴迹方向一致,均以北东、北东东向为主,反映出何家营地区构造变形主要受控于来自雪峰山方向的挤压作用。

     

A Tidal Semidiurnal Harmonic in the Black Sea Dynamics according to Numerical Modeling Results

The parameters of barotropic and baroclinic oscillations in the subinertial range have been obtained by numerical simulations of the Black Sea circulation using a model developed at the Marchuk Institute of Numerical Mathematics, Russian Academy of Sciences. The structures and periods of barotropic and baroclinic seiches are in good agreement with the known theoretical predictions and results of numerical modeling of seiches obtained for the Black Sea subbasins.     

The geological and geodynamic evolution of the eastern Black Sea basin: insights from 2-D and 3-D tectonic modelling

Subsidence mechanisms that may have controlled the evolution of the eastern Black Sea have been studied and simulated using a numerical model that integrates structural, thermal, isostatic and surface processes in both two- (2-D) and three-dimensions (3-D). The model enables the forward modelling of extensional basin evolution followed by deformation due to subsequent extensional and compressional events. Seismic data show that the eastern Black Sea has evolved via a sequence of interrelated tectonic events that began with early Tertiary rifting followed by several phases of compression, mainly confined to the edges of the basin. A large magnitude (approximately 12 km) of regional subsidence also occurred in the central basin throughout the Tertiary. Models that simulate the magnitude of observed fault controlled extension (β=1.13) do not reproduce the total depth of the basin. Similarly, the modelling of compressional deformation around the edges of the basin does little to enhance subsidence in the central basin. A modelling approach that quantifies lithosphere extension according to the amount of observed crustal thinning and thickening across the basin provides the closest match to overall subsidence. The modelling also shows that deep crustal and mantle–lithosphere processes can significantly influence the rate and magnitude of syn- to post-rift subsidence and shows that such mechanisms may have played an important role in forming the anomalously thin syn-rift and thick Miocene–Quaternary sequences observed in the basin. It is also suggested that extension of a 40–45 km thick pre-rift crust is required to generate the observed magnitude of total subsidence when considering a realistic bathymetry.     

Dating and correlation of reference seismic horizons in the Laptev Sea Basin

Four seismic horizons (L1, L2, L3, and L4) were recognized in the Laptev Sea Basin. The seismic complexes that lie between the horizons were found and dated (125-55.8, 55.8-33.9, 33.9-5.3, and 5.3-0Ma). A Paleozoic carbonate plate exists in the southwestern Laptev Sea Basin below the L1 horizon. Rifting in the Laptev Sea Basin began shortly after the Verkhoyansk orogeny ended at about 125 Ma BP. The evolution of the Laptev Sea Basin is correlated with that of the Eurasian Basin and the climatic history of the region.     

塔里木盆地至黑海一带晚第三纪沉积特征及古地理环境

在前人研究基础上，通过对塔里木盆地至黑海一带晚第三纪地层主要剖面沉积特征的对比分析，参考板块构造的研究成果，初步论述了本区古地中海（特提斯洋）在晚第三纪的存在，消失及演变过程，认为咸海，里海和黑海均形成于晚第三纪，是古地中海水退出后保存在大陆上的残留海或淡化海，对研究区晚第三纪的古气候及成矿作用，也作了简要阐述。     

Growth of normal faults in multilayer sequences: A 3D seismic case study from the Egersund Basin,Norwegian North Sea

We investigate the structural style and evolution of a salt-influenced, extensional fault array in the Egersund Basin (Norwegian North Sea) through analysis of 3D reflection seismic and well data. Analysis of fault geometry/morphology, throw distribution and syn-kinematic strata reveal an intricate but systematic style of displacement and growth, suggesting an evolution of (1) initial syn-sedimentary fault growth contemporaneous with salt mobilization initiated during the Late Triassic, (2) cessation of fault activity and burial of the stagnant fault tips, and (3) subsequent nucleation of new faults in the cover above contemporaneous salt re-mobilization initiated during the Late Cretaceous, with downward propagation and linkage with faults. Stage 3 was apparently largely controlled by salt mobilization in response to basin inversion, as reactivated faults are located where the underlying salt is thick, while the non-reactivated faults are found where salt is depleted. Based on the 3D-throw analyses, we conclude that a combination of basement faulting and salt (re-) mobilization is the driving mechanisms behind fault activation and reactivation. Even though the sub- and supra-salt faults are mainly geometrically decoupled through the salt, a kinematic coupling must have existed as sub-salt faults still affected nucleation and localization of the cover faults.     

Analysis of the operative model of hydrophysical field results in the White Sea from July to August 2008

Doklady Earth Sciences -     

北京市平谷盆地地下水三维数值模拟及管理应用

为缓解北京城区的用水紧张问题,平谷区建立了王都庄和中桥两个应急水源地。持续过量的开采导致盆地内水位急剧下降。为研究大规模开采对平谷盆地地下水系统的影响,并分析不同地区的开采潜力,本文建立了合理刻画三维地下水流动特征的数值模型,对五种不同的开采方案进行模拟。模拟结果表明,丰水条件下地下水位回升明显,王都庄水源地补给条件优越,尤其是盆地上游地区,具有更大的开采潜力;而盆地中下部应适当限制开采,避免水位下降过快。高仿真的数值模型可作为强有力的管理辅助工具,为地下水资源分析及合理利用提供科学的技术支持。     

A paleogeographic model of a Cenomanian-Turonian anoxic event in Central and East Black Sea Regions

The paper presents the sedimentological and geochemical characteristics of the Cenomanian-Turonian oceanic anoxic event (OAE-2) based on eight sections in the Central and East Black Sea Regions. A series of paleogeographic models of the OAE-2 is suggested based on Crimean and Caucasian sections.     

Simulated annealing in 3-D seismic modelling and elastic structure of the mediterranean basin

3-D elastic structures images of the Mediterranean basin are obtained by solving a tomographic problem by means of a simulated annealing algorithm. The database consists of local Rayleigh wave group velocities determined for the fundamental mode in the 10–90s period range. These local velocities were obtained from surface wavetrains recorded at very broad band stations of MEDNET network. From a methodological point of view, the characteristics of the annealing algorithm and the amount of time required for computation suggest the implementation of parallel computational procedures to shorten the computational time. According to the thermodynamic analogies used in the annealing algorithm, we propose an alternative procedure to estimate uncertainties and correlations for variables defining the elastic model (shear velocities and layer thicknesses) without necessity of computing partial derivatives. From an applied point of view, the 3-D elastic model obtained shows, as main results, relevant differences for the eastern and western pans of the Mediterranean basin, specially down to 60 km. The changes in the position of the top and bottom asthenosphere surfaces can also be followed throughout the Mediterranean basin; remarkably, these changes are in agreement with some tectonic features.     

A new algorithm to model the dynamics of 3-D bonded rigid bodies with rotations

In this paper we propose a new algorithm to simulate the dynamics of 3-D interacting rigid bodies. Six degrees of freedom are introduced to describe a single 3-D body or particle, and six relative motions and interactions are permitted between bonded bodies. We develop a new decomposition technique for 3-D rotation and pay particular attention to the fact that an arbitrary relative rotation between two coordinate systems or two rigid bodies can not be decomposed into three mutually independent rotations around three orthogonal axes. However, it can be decomposed into two rotations, one pure axial rotation around the line between the centers of two bodies, and another rotation on a specified plane controlled by another parameter. These two rotations, corresponding to the relative axial twisting and bending in our model, are sequence-independent. Therefore all interactions due to the relative translational and rotational motions between linked bodies can be uniquely determined using such a two-step decomposition technique. A complete algorithm for one such simulation is presented. Compared with existing methods, this algorithm is physically more reliable and has greater numerical accuracy.     

A cross section of the eastern Betic Cordillera (SE Spain) according field data and a seismic reflection profile

The BT3 multichannel seismic profile was acquired by the C.G.G. (Compagnie General de Géophysique) in 1977 for hydrocarbon exploration in the eastern Betic Cordillera. REXIMseis Ltd scanned and vectorized a paper copy and then performed post-stack processing, including coherence filtering and deconvolution. The receiver functions of a broad-band seismic station located near the village of Vélez Rubio, at the SE end of the profile, were analysed by Julia et al. [Julia, J., Mancilla, F., Morales, J., 2005. Seismic signature of intracrustal magmatic intrusions in the Eastern Betics (Internal Zone), SE Iberia, Geophysical Research Letters 32, L16304, doi:10.1029/2005GL023274.] to determine the structure of the underlying crust. We have used these Vp data to convert the profile to depth. The profile has a mean SE–NW trend, with a SE-Section 44 km in length followed by a NW-Section 20 km in length. The record includes the first 4 s (twtt), which corresponds to 11 km.Two main areas can be seen in the profile. At the SE-end, a band of high-amplitude discontinuous reflectors dips towards the north. The band is 100 to 200 ms thick, increasing even more northwards. This band reaches the surface at the top of the Maláguide Complex (the upper complex of the Internal Zones). Above these reflectors, an area with chaotic seismic facies and no reflectors corresponds to the outcrops of the olistostromes and turbidites of the Solana Formation, and it is in turn overlain by discontinuous reflectors of the Subbetic rocks.At the NW-end of the profile, a set of high-amplitude continuous reflectors with SE dips point to the location of the Prebetic. Below this section, oblique reflectors of intermediate amplitude indicate the Variscan basement. Over the Prebetic, we have marked the basal thrusts of the Intermediate Units and the Subbetic. Using this seismic data, as well as field observations, we propose a geological cross-section of the upper crust of the eastern Betic Cordillera and a model of the most recent evolution of the orogen. In this model, the Internal Zones and the Subbetic have been welded together from the Middle Burdigalian to the present day and acted as an orogenic wedge that deformed the Intermediate Units and the Prebetic.     

A statistical assessment of the uncertainty in a 3-D geological framework model

Three-dimensional framework models are the state of the art to present geologists’ understanding of a region in a form that can be used to support planning and decision making. However, there is little information on the uncertainty of such framework models. This paper reports an experiment in which five geologists each produced a framework model of a single region in the east of England. Each modeller was provided with a unique set of borehole observations from which to make their model. Each set was made by withholding five unique validation boreholes from the set of all available boreholes. The models could then be compared with the validation observations. There was no significant between-modeller source of variation in framework model error. There was no evidence of systematic bias in the modelled depth for any unit, and a statistically significant but small tendency for the mean error to increase with depth below the surface. The confidence interval for the predicted height of a surface at a point ranged from ±5.6 m to ±6.4 m. There was some evidence that the variance of the model error increased with depth, but no evidence that it differed between modellers or varied with the number of close-neighbouring boreholes or distance to the outcrop. These results are specific to the area that has been modelled, with relatively simple geology, and reflect the relatively dense set of boreholes available for modelling. The method should be applied under a range of conditions to derive more general conclusions.     

北黄海盆地某区块火成岩地震识别与预测

利用北黄海盆地某区块最新采集处理的三维地震资料,通过钻、测井资料综合分析建立井震关系。使用地震相分析、叠前反演以及多属性综合预测等技术刻画火成岩的形态和空间展布特征,总结本区火成岩在地震剖面上的响应特征及空间变化规律。综合预测结果显示研究区内东部发育有规模巨大的潜山型火成岩,西北部发育有侵入岩体刺穿,其他区域主要发育小规模岩株、岩墙或岩脉状侵入岩。