NOMOGRAMS FOR SOLVING EQUATIONS IN MULTILAYER AND DIPPING LAYER CASES*

Nomograms for solving equations in multilayer and dipping layer cases are presented. The nomograms constructed are used to solve the following equations: I. Intercept-time formula. 2. Critical distance formula. 3. Critical angle formula. 4. Critical angle and dip angle formula. 5. Vertical depth formula.     

Erg margin of the Permian White Rim Sandstone, SE Utah

The Permian White Rim Sandstone of the Canyonlands National Park, Utah, contains a wide variety of sedimentary structures and features that largely result from stages in erg migration and marine influence on an erg margin. Three spatially distinct lithological and depositional facies are recognized and can be distinguished as informal units within the formation. The aeolian dune facies is composed predominantly of fine-grained cross-stratified sandstone of the White Rim erg. This facies is the most widespread and comprises the bulk of the formation. Within the aeolian dune facies are small subfacies that represent interdune deposits. A sheet sand facies, composed of parallel-bedded sandstone, makes up a significant part of the lowest part of the White Rim Formation. This facies appears to have been the precursor or leading (progradational) edge to the main erg system. The final facies is a reworked or veneer facies of rippled to disturbed sandstone that is localized in its extent. It is restricted to the upper few metres of the formation and is transitional in some places to the Triassic Moenkopi Formation. This veneer facies contains many structures which indicate marine reworking as well as periods of desiccation or subaerial exposure. Some previous interpretations of the White Rim Sandstone have tended to classify the whole formation as one depositional setting. It is clear that at the margin of a sand sea, as shown in the White Rim Sandstone, there are transitional facies due to the interactions with other environments. Additionally, variation in the stratigraphic relationships of facies can be related to stages of erg migration. Erg margin deposits preceded central erg development. Erg initiation occurred during a probable relative sea level low. Sea level influence is recorded at the top of the formation because erg termination accompanied a relative sea level high with cut-off of sand supply. Transgression of the Permian Kaibab Sea over the White Rim erg was probably the main process in preservation of original dune topographic relief. Sea level fluctuations also may have affected distribution of facies and the complexities of structures at the erg margin. Subsequent fluvial reworking of the veneer facies may have obliterated Late Permian features during lowest Triassic Moenkopi deposition.     

Erosion control for mudstone soil with ventilation and watertight resin

To accelerate the re-vegetation of exposed landslide areas, hydroseeding for soil and water conservation has been widely applied as one of the economically feasible ways. However, effect durations of different hydroseeding materials are different, the formulation density has a certain effect on plant growth and the addictives may exude. This paper presents laboratory experiments of soil erosion, exuding water quality and soil hardness by using a rainfall simulator with different conditions of slope, rainfall intensity and medication density. The results showed that soil erosion decreased significantly, suggesting a good erosion-resisting effect by the ventilation and watertight resin. No significant variation of the exuded water was observed during testing, which indicates that after gelling, the ventilation and watertight resin are unlikely to release chemical substances. It was found that high resin density will result in poor workability as well as high costs; adverse will cause the mudstone to fracture due to raindrops since cracks are common to soil surface. The weatherability after spraying and its effect on plant vegetation still need further investigation.     

A STUDY ON THE DIRECT INTERPRETATION OF RESISTIVITY SOUNDING DATA MEASURED BY WENNER ELECTRODE CONFIGURATION*

This paper describes certain procedures for deriving from the apparent resistivity data as measured by the Wenner electrode configuration two functions, known as the kernel and the associated kernel respectively, both of which are functions dependent on the layer resistivities and thicknesses. It is shown that the solution of the integral equation for the Wenner electrode configuration leads directly to the associated kernel, from which an integral expression expressing the kernel explicitly in terms of the apparent resistivity function can be derived. The kernel is related to the associated kernel by a simple functional equation where K₁(λ) is the kernel and B₁(λ) the associated kernel. Composite numerical quadrature formulas and also integration formulas based on partial approximation of the integrand by a parabolic arc within a small interval are developed for the calculation of the kernel and the associated kernel from apparent resistivity data. Both techniques of integration require knowledge of the values of the apparent resistivity function at points lying between the input data points. It is shown that such unknown values of the apparent resistivity function can satisfactorily be obtained by interpolation using the least-squares method. The least-squares method involves the approximation of the observed set of apparent resistivity data by orthogonal polynomials generated by Forsythe's method (Forsythe 1956). Values of the kernel and of the associated kernel obtained by numerical integration compare favourably with the corresponding theoretical values of these functions.     

安徽省淮北地区矽卡岩型矿床成矿系列及成矿规律

淮北地区是皖北重要的铁铜成矿区,为系统总结该区矽卡岩型矿床成矿系列及成矿规律,基于近年来在该地区取得的找矿成果,通过系统研究已知矿床地质特征和成矿地质条件,结合成岩、成矿年代学特征,认为该区有3个成矿系列: 与高钾钙碱性侵入岩有关的矽卡岩型铁铜金成矿系列、与高钾钙碱性侵入岩有关的矽卡岩型铁-石膏成矿系列和与二长花岗岩有关的矽卡岩型铁-轻稀土成矿系列。分别论述了该区4个典型矿床的地质特征及成矿规律,认为该区为两阶段成矿,成矿空间受深断裂、弧形构造和岩浆岩带的共同控制。最终建立了该区早白垩世早期“前常式”、“杨桥孜式”和“王场式”铁多金属矿床和早白垩世晚期“旗杆楼式”铁-轻稀土矿床的区域成矿模式。     

考虑波浪引起的主应力轴旋转效应的砂土本构模型及其验证

Principal stress axes rotation influences the stress-strain behavior of sand under wave loading. A constitutive model for sand, which considers principal stress orientation and is based on generalized ...     

Influence of South China Sea SST and the ENSO on Winter Rainfall over South China

The present study investigates the influence of South China Sea (SCS) SST and ENSO on winter (January--February--March; JFM) rainfall over South China and its dynamic processes by using station observations for the period 1951--2003, Met Office Hadley Center SST data for the period 1900--2008, and ERA-40 reanalysis data for the period 1958--2002. It is found that JFM rainfall over South China has a significant correlation with Nino-3 and SCS SST. Analyses show that in El Nino or positive SCS SST anomaly years, southwesterly anomalies at 700 hPa dominate over the South China Sea, which in turn transports more moisture into South China and favors increased rainfall. A partial regression analysis indicates that the independent ENSO influence on winter rainfall occurs mainly over South China, whereas SCS SST has a larger independent influence on winter rainfall in northern part of South China. The temperature over South China shows an obvious decrease at 300 hPa and an increase near the surface, with the former induced by Nino-3 and the latter SCS SST anomalies. This enhances the convective instability and weakens the potential vorticity (PV), which explains the strengthening of ascending motion and the increase of JFM rainfall over South China.     

安徽宣城麻姑山——荞麦山地区铜多金属矿地质特征及找矿方向

安徽宣城麻姑山—荞麦山地区是长江中下游成矿带的重要组成部分,在该区已发现茶亭斑岩型铜金矿、荞麦山层控矽卡岩型铜硫钨多金属矿及魏墩热液充填型锌硫矿。通过总结近年来该地区地质勘查成果,结合区域地质背景和铜多金属矿地质特征,探讨该区铜多金属矿的矿化规律和找矿方向。该区重要控矿层位为石炭系黄龙组、船山组;重要控矿构造为次一级倒转背斜的倒转翼及泥盆系五通组与石炭系黄龙组、船山组接触面;与成矿有关的岩浆岩主要为燕山晚期花岗闪长斑岩。这些控矿因素可指明该区下一步找矿方向。