华南留茶坡组与灯影组的地层对比

以硅质岩为特征的留茶坡组广泛地分布于湘、黔、渝等华南地区。在留茶坡组中普遍夹有厚度不一的白云岩层或泥质粉砂岩和其上0～10 cm厚的紫红色黏土岩。在湘西桃源,以宏体藻类为主的"武陵山生物群"产自于此白云岩层之下的硅质岩所夹黑色页岩中。该宏体生物群在化石的形态类型、组合面貌以及埋藏和保存特征等方面与产自于陡山沱组顶部的鄂西"庙河生物群"和黔东北"瓮会生物群"较为相似。但与后两个生物群相比较,"武陵山生物群"中藻体分枝的宏体藻类贫乏,且宏体生物的结构构造相对简单、演化水平相对较低,时代应为伊迪卡拉(震旦)纪陡山沱期晚期。而留茶坡组中所夹的白云岩层或泥质粉砂岩可能系灯影峡期的海平面下降、地壳上升在相对深水相地区的反映。湘黔一带留茶坡组的时代应为伊迪卡拉(震旦)纪至早寒武世早期。     

New approximate solution for time-fractional coupled KdV equations by generalised differential transform method

In this paper, the generalised two-dimensional differential transform method (DTM) of solving the time-fractional coupled KdV equations is proposed. The fractional derivative is described in the Caputo sense. The presented method is a numerical method based on the generalised Taylor series expansion which constructs an analytical solution in the form of a polynomial. An illustrative example shows that the generalised two-dimensional DTM is effective for the coupled equations.     

大火成岩省的类型、成因及其地球系统意义

大火成岩省指的是板块内部在相对短的时间间隔内(通常<3 Ma)巨量的岩浆喷发和侵入形成的火成岩省(面积超过10⁵ km²,体积超过10⁵ km³)。自此概念提出至今,在许多方面都取得了重要进展,但对于其成因以及对大陆裂解、物质循环、环境效应、生物灭绝等方面还存在着诸多争论。本文在回顾大火成岩省定义及其演变的基础上,对上述问题进行了全面的讨论,内容包括：(1)镁铁质大火成岩省(MLIP)成因的地幔柱模型及其存在的问题;(2)水在MLIP形成过程中的作用;(3) MLIP成因的其他替代模型;(4)硅质大火成岩省(SLIP)的成因及其与MLIP之间的关系;(5)大火成岩省和超大陆裂解之间的耦合关系;(6)大火成岩省与碳、硫循环及其对全球环境和生物大规模绝灭的影响;(7)大火成岩省与全球海平面升高、温室效应以及大洋缺氧事件的关系;(8)大火成岩省的地表地形效应。最后提出了大火成岩省研究中有待解决的几个重要问题和可能的解决思路。     

莺歌海盆地LD10气田砂岩储层可动流体特征与天然气充注下限

针对近海盆地低渗砂岩气藏含气量较低,物性下限不明显的难题,本文进行了莺歌海盆地LD10气田低渗砂岩储层流体可动性、天然气充注下限及充注过程的研究。结果表明：研究区发育3种类型储层,分别为：(1)强溶蚀-大孔粗喉可动型Ⅰ类储层,质量最好,大孔喉为优势运移通道;(2)弱溶蚀-中孔细喉部分可动型Ⅱ类储层,较高动力下储层可动流体占比高;(3)致密-微孔管束喉道束缚型Ⅲ类储层,发育极少大孔喉,含气饱和度差异较大。大孔喉分布、储层物性是控制低渗储层流体可动性的主要因素。综合考虑储层流体可动性的微观与宏观因素,认为LD10气田低渗砂岩储层气体可动性的孔喉半径下限为0.1μm,渗透率下限为0.125×10^-3μm²,Ⅲ类储层致密,可作为遮挡层。天然气充注动力较低或充注初期,Ⅰ类储层为气藏聚集的有利区;当天然气充注动力充足时,Ⅰ类储层既是优势运移通道,也是气藏的优势聚集区,Ⅱ类储层为有效储层。研究成果对低渗砂岩储层有效性的判别和气藏有利区的预测具有借鉴意义。     

暴雨预报中潜热能场的应用

利用能量天气学原理,统计了3种天气类型的暴雨过程中潜热能场的水平分布特征。对1999年8月11日出现在山东省的大范围暴雨天气过程(99.8),分别就潜热能场水平分布特征、潜热能场垂直分布特征、能量锋生特征进行了分析。结果表明,潜热能场对暴雨预报有较好的指示作用,仅仅是能量高值区并不一定能产生大降水,当较强的能量锋区(或冷空气)与高能轴交汇、能量锋生函数负值区域移入当地,低层辐合条件较好时,预示强降水将要发生。"99.8"大暴雨主要发生在能量锋区与高能轴线交汇的地方,进而沿高能轴右侧向锋区密度较大地区移动,高能轴顶端的右前方、冷槽的后部也是强降水易发生的地区。     

Simulations of water movement and solute transport through different soil texture configurations under negative‐pressure irrigation

This study examined the effects of different soil texture configurations on water movement and solute transport to provide a reliable scientific basis for the application of negative‐pressure irrigation (NPI) technology. HYDRUS‐2D was used to analyse water movement and solute transport under NPI. The main results are as follows: (a) HYDRUS‐2D can be used to simulate water movement and solute transport under NPI, as there was good agreement between the simulated and measured values for water contents, NaCl concentrations, cumulative water infiltration, and wetting distances in the horizontal and vertical directions; the Nash–Sutcliffe efficiency coefficients were in the range of 0.94–0.97. (b) Layered soils have obvious effects on water movement under NPI. With the emitter position in the loam layer, when a coarse texture of loamy sand was present below the loam layer (namely, L‐LS), irrigation water accumulated in the topsoil, and this led to an increase in evaporation compared with the homogeneous loam profile. However, fine texture silty loam or silty clay loam layers beneath the loam layer (namely, L‐SiL or L‐SiCL, respectively) was more conducive to water infiltration into the lower layer, and this increased the amount of water infiltration and simultaneously reduced the surface evaporation effectively. (c) Layered soils have obvious effects on solute transport under NPI, and salt accumulation will readily occur in the clay‐rich soil layer at the interface. The maximum soil salt accumulation of L‐LS occurred above the soil interface between the two soil layers with a value of 21.80 g/kg; however, for L‐SiCL and L‐SiL, the maximum salt accumulation occurred below the soil interface between the two soil layers, with values of 23.80 g/kg and 20.08 g/kg, respectively. (d) Interlayered soils showed remarkable changes in the water infiltration characteristics and salt‐leaching intensities under NPI, and the properties for the soil profile with a silty loam interlayer were better than those for the soil profile with a silty clay loam interlayer. The soil profile with a loamy sand interlayer had the lowest amount of water infiltration, which resulted in reductions of the salt‐leaching intensities. Thus, NPI is clearly not suitable for loamy sand soil. Overall, the results demonstrated that soil texture configurations affected water movement and solute transport under NPI. Therefore, careful consideration should be given to the use of NPI to achieve target soil water and solution conditions and reduce water loss.     

我国土壤中结合态硒的含量和分布规律

本文提出并建立了Jackson法系统分离土壤中不同形态硒的实验程序,研究了我国几种土壤表层(0—20cm)中硒的结合形态及其地理分布规律,并对植物可利用性作了评价。     

AR6659光球色球的磁场速度场的演化特征及其与大耀斑的关系

ＡＲ６６５９是２２周以来最重要的一个活动区，它爆发了２２周最强大的高能事件。本文用云南天文台的光球、色球精细结构照片和北京天文台怀柔站的磁场速度场资料，分析了该活动区磁场速度场的二维位形和大耀斑期间的演化特征。本文分析的４个大耀斑均爆发在中性线附近的Ｎ极区磁场梯度大的地方及色球速度场的红移区。偏带观测也显示耀斑物质是向红端移动的。耀斑波沿横场传播在离本黑子群几万至十几万公里的地方激起感生耀斑，在原生耀斑与感生耀斑之间往往有耀斑环相连。此外，本文还从演化特征出发分析了耀斑爆发前活动区等离子体的宏观不稳定性。     

应用综合前兆异常月频度判定地震进入中短期的研究

应用震后资料总结和震前所判定的异常资料研究了１９７５－１９９６年的４４个震次,结果表明,地震孕育进入中短期时无论是近场前兆异常、近场前兆异常,还是远、近场均有的前兆异常,其综合前兆异常月频率度一般同时呈现出２个明显特征;（１）月频度累加曲线呈现为非线性加速形态;（２）同时月频度变化速率出现异常,二相结合,一般可以判定了地震孕育是否进入短期阶段。由于研究内容广泛和取得的中短期特征明显,因此所得结果     

Magnetic and mineralogical characteristics of hydrocarbon microseepage above oil/gas reservoirs of Tuoku region, northern Tarim Basin, China

The Tuoku region in northern Tarim Basin of China is a key area for studying oil/gas reservoir rocks. The magnetic and mineralogical parameters of well cuttings from two wells, well S₇, situated on oil/gas field, and well S₆, at an oil/water interface, were measured. The two wells are located in the same structure with similar strata and types of lithology, but well S₆ is a showing well of oil and gas 5 km northwest of well S₇. The purpose of this paper is to evaluate the possibility and distribution of secondary magnetic alteration that may have occurred due to hydrocarbon migration above an oil/gas accumulation. It is concluded that the magnetism of well cuttings from major strata in well S₇, including source rocks, oil reservoir rocks and cap rocks, and in Quaternary (Q) soil is higher than that from well S₆. The Cambrian oil-bearing strata and cap rocks have even higher magnetism in well S₇. The shape and parameters of magnetic hysteresis loops indicate that soft (H _c<20 mT,H _s<0.3 T) ferrimagnetic components dominate the magnetic carriers within the strongly magnetic strata of well S₇, whereas a mixed paramagnetic and ferrimagnetic distribution occurs in well S₆ (for example, low coecivityH _c and nonsaturating magnetized character). Analysis of heavy minerals shows that the contents of iron oxide (magnetite, maghemite and hematite) in well S₇ are often higher than those in well S₆. The magnetite content in samples of cuttings from Cambrian rocks can reach 9.7% in oil-bearing strata in well S₇, and in strata Ekm and N₁j are 1.215% and1.498%, respectively. Typical spherical magnetite grains are found within the main source rocks and the soils in well S₇. By analysis of surface microtexture and of trace element contents, we infer that the spherical magnetite is composed of aggregates of ultrafine particles that are probably authigenic magnetite formed in a hydrocarbon halo background. Project supported by the National Natural Science Foundation of China and the Geological Industry Foundation of China (Grant No. 49374216) and Foundation of the State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation of China (Grant No. 9608).