Aminostratigraphy of surface and subsurface Quaternary sediments,North Carolina coastal plain,USA

The Quaternary stratigraphy and geochronology of the Albemarle Embayment of the North Carolina (NC) Coastal Plain is examined using amino acid racemization (AAR) in marine mollusks, in combination with geophysical, lithologic, and biostratigraphic analysis of 28 rotasonic cores drilled between 2002 and 2006. The Albemarle Embayment is bounded by structural highs to the north and south, and Quaternary strata thin westward toward the Suffolk paleoshoreline, frequently referred to as the Suffolk Scarp. The Quaternary section is up to ～90 m thick, consists of a variety of estuarine, shelf, back-barrier, and lagoonal deposits, and has been influenced by multiple sea-level cycles. The temporal resolution of the amino acid racemization method is tested statistically and with the stratigraphic control provided by this geologic framework, and it is then applied to the correlation and age estimation of subsurface units throughout the region. Over 500 specimens (primarily Mercenaria and Mulinia) from the subsurface section have been analyzed using either gas chromatographic (GC) or reverse-phase liquid chromatographic (RPLC) techniques. The subsurface stratigraphic data are compared with AAR results from numerous natural or excavated exposures from the surrounding region, as well as results from NC beach collections, to develop a comprehensive aminostratigraphic database for the entire Quaternary record within the NC coastal system. Age mixing, recognized in the beach collections, is also seen in subsurface sections, usually where major seismic reflections or core lithology indicate the presence of stratigraphic discontinuities. Kinetic models for racemization are tested within the regional stratigraphic framework, using either radiocarbon or U-series calibrations or comparison with regional biostratigraphy. Three major Pleistocene aminozones [AZ2, AZ3, and AZ4] are found throughout the region, all being found in superposition in several cores. Each can be subdivided, yielding a total of at least eight stratigraphically and statistically distinct aminozones. Kinetic modeling, supplemented with local calibration, indicates that these aminozones represent depositional events ranging from ～80 ka to nearly 2 Ma. Three prominent seismic reflections are interpreted to represent the base of the early, middle, and late Pleistocene, respectively, roughly 2 Ma, 800 ka, and 130 ka. The large number of samples and the available stratigraphic control provide new insights into the capabilities and limitations of aminostratigraphic methods in assessing relative and numerical ages of Atlantic Coastal Plain Quaternary deposits.     

A new determination of the orbit and masses of the Be binary system δ Scorpii

The binary star δ Sco (HD143275) underwent remarkable brightening in the visible in 2000, and continues to be irregularly variable. The system was observed with the Sydney University Stellar Interferometer (SUSI) in 1999, 2000, 2001, 2006 and 2007. The 1999 observations were consistent with predictions based on the previously published orbital elements. The subsequent observations can only be explained by assuming that an optically bright emission region with an angular size of  ≳2 ± 1 mas  formed around the primary in 2000. By 2006/2007 the size of this region grew to an estimated ≳4 mas.
We have determined a consistent set of orbital elements by simultaneously fitting all the published interferometric and spectroscopic data as well as the SUSI data reported here. The resulting elements and the brightness ratio for the system measured prior to the outburst in 2000 have been used to estimate the masses of the components. We find   M_A = 15 ± 7 M_⊙  and   M_B = 8.0 ± 3.6 M_⊙  . The dynamical parallax is estimated to be  7.03 ± 0.15 mas  , which is in good agreement with the revised Hipparcos parallax.     

Ionospheric Tomography Network of Egypt: A New Receiver Network in Support of the International Heliophysical Year

The International Heliophysical Year (IHY) 2007 is an international scientific program designed to coordinate observations of the heliosphere, the region of space from the solar surface through the solar wind and various planetary magnetospheres to the planetary upper atmospheres. A particular emphasis is given to the development of long-term international collaborations that will study the external drivers to the space environment and climate. The Ionospheric Tomography Network of Egypt (ITNE) is one such collaboration. It is a new chain of ionospheric tomography receivers that will be deployed to investigate the equatorial regions of the Earth’s ionosphere. The distribution of plasma density within 20° of the magnetic equator is highly sensitive to forcing from the solar wind through a process known as the equatorial fountain. ITNE will provide new observations of the density structures associated with the equatorial fountain.     

Statistical significance of trends in monthly heavy precipitation over the US

Trends in monthly heavy precipitation, defined by a return period of one year, are assessed for statistical significance in observations and Global Climate Model (GCM) simulations over the contiguous United States using Monte Carlo non-parametric and parametric bootstrapping techniques. The results from the two Monte Carlo approaches are found to be similar to each other, and also to the traditional non-parametric Kendall’s τ test, implying the robustness of the approach. Two different observational data-sets are employed to test for trends in monthly heavy precipitation and are found to exhibit consistent results. Both data-sets demonstrate upward trends, one of which is found to be statistically significant at the 95% confidence level. Upward trends similar to observations are observed in some climate model simulations of the twentieth century, but their statistical significance is marginal. For projections of the twenty-first century, a statistically significant upwards trend is observed in most of the climate models analyzed. The change in the simulated precipitation variance appears to be more important in the twenty-first century projections than changes in the mean precipitation. Stochastic fluctuations of the climate-system are found to be dominate monthly heavy precipitation as some GCM simulations show a downwards trend even in the twenty-first century projections when the greenhouse gas forcings are strong.     

云南个旧期北山七段玄武岩中磁黄铁矿结构变化分形特征

微观尺度上土壤孔隙、岩石孔洞缝、矿物组构的分形与多重分形研究受到广泛关注,典型的P-A(周长-面积)分形模型、盒子维数等也广泛应用于其中.云南个旧锡多金属矿床老厂期北山垂向上七段玄武岩发育完整,但对其形成机理及对成矿的贡献有较多的争议.这七层玄武岩中磁黄铁矿广泛发育.基于GIS的P-A分形模型研究磁黄铁矿颗粒的大小、颗粒的不规则性及空间分布特征,探讨磁黄铁矿这一标志性矿物在不同层段玄武岩中的变化情况,并为玄武岩的成因给出新的解释.结合盒子维数,分形分析结果显示,从第一段玄武岩到第七段玄武岩磁黄铁矿的面积分维DA和周长分维D,p总体保持不变的态势;而周长-面积分维DPA却有逐渐增大的趋势.DPA增大表明随着深度的增加,磁黄铁矿颗粒不规则性增强.     

山东渤南油田古近系沙河街组沙二段及沙三段低渗透储层成岩储集相

渤南油田位于济阳坳陷的渤南洼陷内,是山东省胜利油田储量最大的亿吨级深层低渗透断块岩性油藏,主要含油层系为古近系沙河街组沙二段和沙三段,属中孔低渗透砂岩储层。低渗透砂岩储层的成因机理十分复杂,为了更精确地预测有效储层的分布及其内部储集性能的差异,应用成岩储集相的概念在渤南油田三区古近系沙河街组开展了低渗透储层质量评价的研究。该项研究是建立在储层沉积相、成岩作用研究的基础上,通过分析低渗透储层成岩作用对储集物性的影响及成岩作用阶段划分,认为造成本区储层砂岩渗透率较低的主要原因是成岩期各种自生矿物的充填和胶结作用。选用流动层带指标、孔隙度、渗透率、粒度中值、泥质含量、孔喉半径均值和变异系数等七项参数,采用聚类分析和判别分析方法,将渤南油田三区古近系沙河街组划分为四类成岩储集相,阐述了各类成岩储集相的特征,并结合沉积相,实现了成岩储集相的时空展布。研究成果将对低渗透砂岩储层的开发起到指导作用。     

古地幔流体及其在大陆克拉通地幔演化中的意义——以华北地台为例

古生代含捕虏体的金伯利岩和新生代含捕虏体的玄武岩同出于华北地台，提供了研究自古生代以来岩石圈演化的深源探针。古生代含金伯利岩的侵位表明古生代时曾存在冷厚的岩石圈；而新生代含捕虏体玄武岩的喷发，表明新生代时存在热薄的岩石圈。岩石圈减薄与“大洋化”是层圈物质交换作用在一定历史阶段中的反映。地幔流体是地幔演化产物，反之又作用于地幔演化。富含地幔流体的幔内剪切带及交代矿物层作为幔内软薄弱带，存在热、流体、化学及机械的耦合，是岩石圈减薄拆沉作用的重要界面位置。     

The geography of the coal industry in the United Kingdom in the 1970s: changing directions?

Conclusion This paper has described some of the changes that have occurred in the geography of the UK's coal industry in a period when decline was the keynote, and attempted to illustrate some of the developments that are occurring in the late 1970s with implementation of the Plan for Coal. Launched at a time when the complete collapse of European energy supply seemed a distinct possibility, that Plan is encountering many problems in its implementation, and its unmodified completion must remain in doubt. The Plan 1974 and its successor embody a fundamental change of direction for the coal industry — from contraction to expansion.But although there is a change of direction at the national scale, at the inter- and intra-regional scales the direction remains largely the same. The dominance of the central coalfields is likely to increase further, while within these areas the trend towards large-scale deep mines in the concealed sections remains strong. Indeed achievement of the new desired direction at the national level, based as it must be on an industry that is price-competitive with other energy sources, may be dependent upon an intensification of these regional trends towards concentration of investment in areas where mining conditions are favourable and high-productivity, low-cost production can be achieved. It is also being recognized that removal of the burden of high-cost inefficient collieries in less favoured, mainly peripheral fields may also be vital to the competitive position:-the overall competitiveness of the industry is ... at present adversely affected by a small proportion of capacity where productivity is low and costs are high, mainly as a result of difficult working conditions. Closure of uneconomic pits as they became worked out will improve the industry's ability to compete with other fuels, (Secretary of State for Energy 1978).It thus appears that in the last quarter of the twentieth century the coal industry in the UK will become more and more focused on especially favoured areas in the central parts of the country, through the twin process of shedding loss-making activities in less favoured peripheral fields, and investing in the ample resources that underline the English lowlands.