Compositions of micas in peraluminous granitoids of the eastern Arabian shield

Compositions and pleochroism of micas in fourteen peraluminous alkali-feldspar granites in the eastern part of the Late Proterozoic Arabian Shield are unlike those of micas (principally biotite) in most calc-alkaline granitoid rocks. Compositions of these micas are distinguished by elevated abundances of Li₂O, F, and numerous cations and by low MgO abundances. These micas, constituents of highly evolved rare-metal enriched granitoids, represent an iron-lithium substitution series that ranges from lithium-poor siderophyllite to lithium-rich ferroan lepidolite. The eastern Arabian Shield also hosts six epizonal granitoids that contain colorless micas. Compositions of these micas, mostly muscovite, and their host granitoids are distinct from those of the iron-lithium micas and their host granitoids. Compositions of the analyzed micas have a number of petrogenetic implications. The twenty granitoids containing these micas form three compositional groups that reflect genesis in particular tectonic regimes; mica compositions define the same three groups. The presence of magmatic muscovite in six of these shallowly crystallized granitoids conflicts with experimental data indicating muscovite stability at pressures greater than 3 kbar. Muscovite in the Arabian granitoids probably results from its non-ideal composition; the presence of muscovite cannot be used as a pressure indicator. Finally, mineral/matrix partition coefficients are significantly greater than 1.0 for a number of cations, the rare-earth elements in particular, in many of the analyzed iron-lithium micas. Involvement of these types of micas in partial melting or fractionation processes can have a major influence on silicate liquid compositions.     

新疆阿合勒铜矿GIS预测时的找矿有利度和空间相关性分析

以新疆阿舍勒地区铜矿GIS预测为实例，说明线型异常和面型异常的找矿有利度分析方法，并给出断裂、有利地层和物化探异常找矿有利度分析的结果。给出计算空间相关性的公式，并研究了不同元素化探异常的空间相关性。最后，研究了不同元素的组合异常，论证了在矿产预测中应用组合异常的必要性并利用GIS进行了找矿有利地段的圈定。     

Telescope and instrument robotization at Dome C

This article reviews the situation for robotization of telescopes and instruments at the Antarctic station Concordia on Dome C. A brain‐storming meeting was held in Tenerife in March 2007 from which this review emerged.We describe and summarize the challenges for night‐time operations of various astronomical experiments at conditions “between Earth and Space” and conclude that robotization is likely a prerequisite for continuous astronomical data taking during the 2000‐hour night at Dome C. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Représentativité de l'échantillonnage géochimique et hydrodynamique en nappe libre du milieu semi-aride (Reliability of geochemical and hydrodynamic sample in a semi-arid water table)

This paper evaluates the reliability of the geochemical and hydrodynamic sampling in a phreatic aquifer of semi-arid Africa. These remarks are based on a dense network and on detailed data collected for about ten years in the Continental Terminal water table near Niamey, Niger. The natural potentiometric fluctuations are seasonal (up to 6 m during the rainy season) and interannual (up to 10 m since the 1960s). Hydrodynamic measurements can be disturbed by artificial flooding into the wells (20% of the network) and by domestic drawings (up to 2 m of lowering). Geochemical characteristics can vary seasonally: isotopic modifications and salinity increase near recharge areas, with more stability further away. They can also vary artificially in wells because of their large opening towards the open air. Artifical increases of salinity of one order of magnitude and contaminations of ¹⁴C activities of up to 20 pmC occur in some wells by atmospheric dust inputs or organic matter which was has fallen into the well. In conclusion, some recommendations are given for a representative sampling in semi-arid phreatic aquifers.     

辽东半岛南部印支造山旋回早期的顺层滑脱构造

辽东半岛南部发育于太古宙基底与青白口系盖层邻接部位的大型韧性剪切带与盖层内顺层固态流变形成的构造群体,是印支造山旋回开始时,在主要来自太平洋方面的构造力驱动下,以盖层与基底的不整合面为主滑脱面发生自东向西近水平多层系顺层剪切滑脱的产物, 称顺层滑脱构造。大范围的顺层滑脱未引起大规模的褶皱—逆冲推覆;同时,主滑脱面也不同于伸展拆离断层。顺层滑脱构造形成后先后被南北向（Ｔ３ —Ｊ１） 和东西向（Ｊ２ —Ｊ３） 等褶皱断裂系叠加改造;基底在晚白垩世的断块运动中大幅度抬升。顺层滑脱构造应该是长期沉降的沉积盆地在进入造山旋回时（ 主褶皱前） 可能出现的构造型式。     

An Observation Operator for Radar Refractivity Change: Comparison of Observations and Convective-Scale Simulations

Weather radar refractivity depends on low-level moisture, temperature, and pressure and is available at high space–time resolutions over large areas. It is of definite meteorological interest for assimilation, verification, and process-study purposes. In this study, the path-averaged refractivity change is simulated from the Arome cloud-resolving atmospheric system analyses and compared with corresponding radar observations over a 35-day period with various meteorological conditions. For that, a novel post-processing procedure is applied to radar data to improve its quality. Also, an observation operator is developed that ingests Arome analyses and simulates a 3-h path-averaged refractivity change. A sensitivity study shows that simulated path-averaged refractivity change is immune to the modelling of the beam height as long as it remains below approximately 60 m above the ground. Comparisons show overall consistency between observed and simulated path-averaged refractivity change, with discrepancies at times that suggest an improvement in analyses once radar refractivity change observations are assimilated. Finally, errors introduced when retrieving local refractivity from path-averaged refractivity are estimated and it is found for our dataset that such retrievals halve the range of usable observations.     

Passive sonar ML estimator for ship propeller speed

The optimal estimator in the maximum-likelihood sense fur the propeller speed of a ship, using underwater radiated cavitation noise generated by the propeller blades, is derived. From the result the number of blades on the propeller can also be derived. Results obtained for real sonar data using a digital implementation of the estimator will be presented     

Energy-Momentum of a Stationary Beam of Light in Teleparallel Gravity

In this paper, we utilize the teleparallel gravity analogs of the energy and momentum definitions of Bergmann-Thomson and Landau-Lifshitz in order to explicitly evaluate the energy distribution (due to matter and fields including gravity) based on the Bonnor space-time, it is shown that for a stationary beam of light, these energy-momentum definitions give the same result. Furthermore, this result supports the viewpoint of Cooperstock and also agree with the previous works by Bringley and Gad.     

光纤光学延迟线及其应用于望远镜干涉阵的可行性研究

本文叙述了一台全新的全光学干涉仪，以此干涉仪为基础，就光纤联接的望远镜干涉阵中用拉伸光纤实现光程补偿的方法在国际上首次进行了研究，在对试验结果进行分析，讨论的基础上肯定了该方法的可行性。