The Early Pleistocene Praetiglian and Ludhamian pollen stages in the North Sea Basin and their relationship to the marine isotope record

In this paper, the currently accepted correlation of the Early Pleistocene Ludhamian stage of England with the Tiglian‐A sub‐stage of the Netherlands is challenged. Recent investigations of Early Pleistocene marine North Sea deposits from a borehole near Noordwijk (the Netherlands) yielded evidence from molluscs, dinoflagellate cysts and sporomorphs for an alternation of warm‐temperate and arctic intervals within the Praetiglian and Tiglian stages. Marine equivalents of the terrestrial‐based pollen sub‐stages Tiglian A and B have been recognised in the upper part of the sequence. A Praetiglian age can be assigned to the lower part of the sequence on the basis of mollusc analysis. Within the Praetiglian, an alternation of warm and cold phases has been recognised from both the dinoflagellate cyst and molluscan records. Three cold phases within the Praetiglian are tentatively correlated with marine isotope stages (MIS) 96–100. The molluscan assemblages provide evidence for climate forcing of the sea level: highest sea levels are reached in the warm‐temperate intervals. Within the Praetiglian, an interval with an acme zone of the dinoflagellate cyst Impagidinium multiplexum, is correlated with the Ludhamian and tentatively linked to MIS 97 and/or MIS 96. The cold molluscan assemblages from the Noordwijk borehole include an acme zone of Megayoldia thraciaeformis, the first and only occurrence of this North Pacific bivalve in the North Sea Basin. Copyright © 2006 John Wiley & Sons, Ltd.     

黑龙江省鸡西盆地南、北两带城子河组精细对比

鸡西盆地被平麻断裂分割成南、北两个条带,多数研究者将南带1煤之下的海相层叠伏于北带海相层或底砾岩之下,称为“城子河组下段”或“石河北组”。利用事件地层学的原理,分析盆地内城子河组早期盆地裂陷、海侵、火山喷发、聚煤等重大事件在地层精细对比方面的意义,甄别出了盆地中重大事件的地层记录．以等时层为基础建立对比框架。通过大量钻井资料追溯对比,认为盆地中坳陷部位的渴湖海湾沉积是南北两带的沉积过渡类型,根据微体古生物研究,南北两带海相层中的沟鞭藻类化石面貌基本一致,南北带的海相层应是同一层位,初步实现了盆地内南、北两个条带城子河组的精细对比,为恢复盆地古地理环境奠定了可靠的基础。     

Size Scaling of Cross Correlation Between Multiple Variables

Reservoir models have large uncertainty because of spatial variability and limited sample data. The ultimate aim is to use simultaneously all available data sources to reduce uncertainty and provide reliable reservoir models for resource assessment and flow simulation. Seismic impedance or some other attribute provides a key source of data for reservoir modeling. These seismic data are at a coarser scale than the hard well data and it not an exact measurement of facies proportions or porosity. A requirement for data integration is the cross-covariance between the well and seismic data.The size-scaling behavior of the cross correlation for different measurement scales was nvestigated. The size-scaling relationship is derived theoretically and validated by numerical studies (including an example with real data). The limit properties of the cross-correlation coefficient when the averaging volume becomes large is shown. After some averaging volume, the volume-dependent cross-correlation coefficient reaches a limit value. This plateau value is controlled mainly by the large-scale behavior of the cross and direct variograms.The cross correlation can increase or decrease with volume support depending on the relative importance of long- and short-scale covariance structures. If the direct and cross variograms are proportional, there is no change in the cross correlation as the averaging volume changes. Our study shows that the volume-dependent cross-correlation coefficient is sensitive to the shape of the cross variogram and differences between the direct variograms of the well data and seismic data.     

Explosion seismic reflections from the Earth’s core

Recent seismological studies have presented evidence for the existence of a layer with ultra-low seismic velocities at the core-mantle boundary at ca. 2900 km depth. We report high-amplitude, high-frequency, and laterally coherent seismic arrivals from three nuclear explosions in Siberia. With recording station intervals of 15 km, the seismic phases are readily correlated and show the presence of a thin, ultra-low velocity zone in a region where it was not previously reported. The duration and complexity of the arrivals are inconsistent with a simple core-mantle boundary and require a hitherto unidentified, kilometre-scale, fine structure in the ultra-low velocity zone. The observations may be explained by a ca. 7 km thick, two-layer, ultra-low velocity zone with exceptional low velocities, which indicate the presence of high percentages of melt (>15%), in particular in the lower part of the zone. Waveform variation implies lateral change in the thickness and physical properties of the ultra-low velocity zone with a wavelength of less than 100 km.     

用非线性映象法作钦州市月降水量预报的研究

选取反映大气环流作用的500hPa的三个因子场:1956～2001年环流特征量、振幅和位相资料作为预报因子与钦州市1957～2002年5月降水量求相关比,将求得的高相关比因子用非线性映象法制作钦州市1995～2002年5月的降水量预报,试报效果明显。     

东南沿海地震区地震活动特性与未来趋势分析

根据地震资料，对东南沿海地震区地震活动特下及未来趋势进行了初步分析与研究，结果表明：（１）从地震活动轮回分析，东南沿海地震区从１９５９年开始的第五个轮回中的地震活动时段，估计将延续到２０３１年前后结束，而后转入本轮回的平静时段；（２）２０００年以前，研究区有可能发生１次Ｍｓ≥６．０地震，到２００５到则最多发生２次；（３）东南沿海地震区下一次发生Ｍｓ≥６．０地震的地区可能在河源－邵武地震带上，尤其可     

膨胀土判别与分类的灰关联分析法

基于灰色系统理论，给出一种用于膨胀土判别与分类的新方法—灰关联分析法。实际算例表明，该法具有简单方便、结果客观可靠等优点。     

A bivariate meta-Gaussian density for use in hydrology

Convenient bivariate densities found in the literature are often unsuitable for modeling hydrologic variates. They either constrain the range of association between variates, or fix the form of the marginal distributions. The bivariate meta-Gaussian density is constructed by embedding the normal quantile transform of each variate into the Gaussian law. The density can represent a full range of association between variates and admits arbitrarily specified marginal distributions. Modeling and estimation can be decomposed into i) independent analyses of the marginal distributions, and ii) investigation of the dependence structure. Both statistical and judgmental estimation procedures are possible. Some comparisons to recent applications of bivariate densities in the hydrologic literature motivate and illustrate the model.     

Organism relics or kerogens in oils as oil-source rock correlation indicator

Organism relics or kerogens in oils are first obsenred by a confocal laser scanning microscope (CLSM) and a transmission electron microscope (TEM). The complexes of kerogens in oils are characterized by the presence of a great variety of microfossils or macerals. These kerogens in oils are mainly the residues of the original organic substances from which oil formed, and minor kerogens from enclosing rocks enter the oils, therefore, the components and types of the kerogens in crude oils can serve as an indirect indicator of oil-source rock correlation. This method was applied to Jurassic oils in the Junggar Basin and the Turpan-Hami Basin, and there are two types of the kerogens in oils: one containing a lot of macerals from terrestrial plants may derive from coals, and the other, characterized by a high content of microscopic algae, fungus spores and Acritarch, may originate from Permian organic matter. In addition, the reflectance of the vitrodetrinites in oils can be used as an indicator of oil-source rock correlation.