大气降水对昆明周围地震活动的调制

本文对比分析了昆明周围地区20余年来的大气降水记录和地震资料,指出旱涝变异确实与地震活动存在着一定的统计联系。其中尤以震前一年洪涝的作用较为突出。在此基础上,提出了一个可预测本区中强地震发生的经验性方法。     

福建建宁黄埠地区金矿化基本特征

通过对建宁黄埠地区金矿地质特征、矿化特点、成矿地质规律的研究，认为该区成矿年龄为91Ma，提出了北西西向碎裂带为主要的含矿构造，并指出该区具有较好的找金远景。     

Hydrocarbon Generating Potential of Mineral—Bituminous Matrix in Source Rocks

Mineral-bituminous matrix(MBM) makes up a major part of source rocks,but its potential in hydrocarbon generation is uncertain,Mineral and organic (Maceral and kerogen) compositions,organic maturity and fluorescence of MBM are studied based on source rock samples from eastern Jiuquan(Jiudong)Basin.The results show that MBM is dominated by inorganic minerals and among the small percentage of organic components those of secondary origins are predominant over the primary species.This strongly indicates that the significance of MBM in hydrocarbon generation is limited.     

准噶尔盆地沙湾凹陷二叠系凝析气藏相态识别及成因分析

近年来,我国中西部陆续发现了资源量较大的凝析气藏,准噶尔盆地沙湾凹陷周缘的多个凝析气藏也显示出深层勘探的潜力。针对沙湾凹陷凝析气藏的烃类流体特征和形成机制不清晰的科学问题,笔者等采用原油物性和地球化学分析测试,运用经验统计法来识别油气藏类型,分析油气相态特征及其来源。主要认识如下：① 沙湾凹陷二叠系主要存在带油环凝析气藏,中佳2- H井为典型带油环凝析气藏井,研究区存在风城组为烃源—断层垂向输导—温压控制的原生型和天然气气侵共同作用形成的次生型凝析气藏;② 结合P—V—T相图分析沙湾凹陷二叠系凝析气藏烃类流体C7+占比较小,挥发性油藏地层温度明显低于临界温度,地饱压差较小,黑油油藏地层流体的临界温度与临界凝析温度都较高且临界压力较小;③ 根据新光井区凝析气藏的气油比要高于13000 m3/m3,且新光1井凝析气藏属于无油环凝析气藏可判断新光1井为原生型凝析气藏;中佳2- H井凝析气藏正构烷烃损失率达到90%,且研究区存在混合来源气,证实该凝析气藏曾遭受气侵作用。笔者等提出的凝析气成因可为研究区下一步油气勘探提供参考,同时也可以为准噶尔盆地凝析气成藏的研究和资源评价提供方法支持。     

Gamma-ray bursts: optical afterglows in the deep Newtonian phase

Gamma-ray burst remnants become trans-relativistic typically in days to tens of days, and they enter the deep Newtonian phase in tens of days to months, during which the majority of shock-accelerated electrons will no longer be highly relativistic. However, a small portion of electrons are still accelerated to ultra-relativistic speeds and are capable of emitting synchrotron radiation. The distribution function for electrons is re-derived here so that synchrotron emission from these relativistic electrons can be calculated. Based on the revised model, optical afterglows from both isotropic fireballs and highly collimated jets are studied numerically, and compared to analytical results. In the beamed cases, it is found that, in addition to the steepening due to the edge effect and the lateral expansion effect, the light curves are universally characterized by a flattening during the deep Newtonian phase.     

713天气雷达数字化系统

本文介绍了用IBM-PC/XT(AT)实现的天气雷达数字化系统的众多功能,分析了系统的工作原理。对于几个关键的技术问题——高速数据录取、软件数字视频积分、地物杂波抑制、座标变换及图象传输,分别给出了解决的方法和详尽的程序方框图。     

Dust supply from river floodplains: the case of the lower Huang He (Yellow River) recorded in a loess–palaeosol sequence from the Mangshan Plateau

The Mangshan Plateau is located on the south bank of the Huang He (Yellow River) just west of the city of Zhengzhou, well outside the Loess Plateau in central China. Mixing models of the grain‐size data indicate that the loess deposits are mixtures of three loess components. Comparison of the mixing model with existing models established for a series of loess–palaeosol sequences from the Loess Plateau indicates that the Mangshan loess has been supplied from a proximal dust source, the Huang He floodplain, during major dust outbreaks. The high accumulation rates, the composition of the loess components, and especially the high proportions of a sandy loess component support this. Owing to the exceptionally high accumulation rates, the Mangshan grain size, magnetic susceptibility and carbonate records provide a high‐resolution archive of environmental and climate change. Copyright © 2008 John Wiley & Sons, Ltd.     

土壤质量评价国外研究进展

土壤是人类赖以生存的根本资源。土壤质量涉及到动植物生产力,大气、水的质量和人类的健康,随着人们对自然资源和环境保护意识的增强,越来越多的国家和地区已将土壤质量评价工作作为实现可持续发展的一个重要方面。通过土壤质量评价,了解土壤管理和利用的现状,为土壤质量的改善及可持续利用提供理论依据和技术支撑。根据国外近10年的研究,总结了主要的评价指标体系和评价方法。评价指标主要包括土壤物理、化学和生物性质3个方面的指标。评价方法分为定性和定量评价,定量评价应用较广,包括土壤质量指数、土壤质量模型、多元线性回归、相对土壤质量法等。掌握和了解国外相关研究的动态,对于开展土地质量地球化学评估及土地的分等定级工作有着重要的意义。     

赣北主要内生金矿床的形成条件

赣北地区的金矿床,可分为含金韧性剪切带型、硅化破碎带型、隐爆角砾岩型和微细粒浸染型等4个类型,其原始成矿物质来源于上地幔,通过火山喷发—沉积作用,形成含金沉积建造和含金火山岩建造.钠、钾质两个系列的花岗质岩石都可以形成金矿床.矿化富集主要通过韧、脆性变形和岩浆隐蔽爆破,产生多次破碎,多期蚀变矿化.在中—低温热液阶段,含矿热液体系的HS~-、Cl~-离子减少,还原介质增加的条件下沉淀富集,形成不同类型的金矿床.     

赣南地区石雷石英闪长岩的成因:岩石化学、副矿物微量元素、锆石U-Pb年代学与Sr-Nd-Hf同位素制约

石雷石英闪长岩是赣南崇-余-犹地区比较特殊的闪长质侵入体。锆石的原位U-Pb定年表明,该岩体侵位于433.5±3.4Ma。全岩主量元素特征上显示出中偏酸性(SiO2=56.92%～64.70%),富Al(Al2O3=14.10%～14.83%),富碱(Alk=6.41%～7.40%)特别是富钾(K2O=3.86%～4.85%),镁、铁含量较高,MgO:3.47%～5.95%,FeOT:5.23%～8.14%以及低磷(P2O5=0.27%～0.4%)的特点;微量元素上主要富集K、Rb、Cs等大离子亲石元素和轻稀土元素,亏损Nb、Ta、Ti、P等高场强元素。磷灰石微量元素特征上显示高度富集稀土元素特别是轻稀土元素的特征;具有Eu的负异常(δEu=0.37～0.45)。ISr位于0.7073～0.7132之间,εNd(t)变化于-8.41～-4.97之间,两阶段钕模式年龄介于1.58～1.86Ga之间,Hf同位素组成相对均一,εHf(t)主要集中变化于-8～-2之间,两阶段Hf模式年龄加权平均为1.77±0.09Ga,这些特征都暗示了该石英闪长质岩体的形成是强烈壳幔相互作用的产物,区内加里东晚期可能发生了局部的岩石圈的减薄。