湘、黔下寒武统黑色岩系型Ni、Mo矿床中有机质与PGE成矿作用研究

湘、黔地区张家界、遵义一带分布有黑色岩系型Ni-Mo-PGE矿床,测试分析表明黑色页岩样品铂族元素含量特征参数∑PGE、Ln(Pd/Pt)、(Ru/Ir)×(Pd/Pt)、Ln[(Ru/Ir)×(Pd/Pt)]均与有机质含量特征参数有较好的相关性.趋势分析显示,铂族元素含量特征参数Ln[(Ru/Ir)×(Pd/Pt)]与总有机碳含量特征参数Ln(Corg)有很好的线性相关,线性相关公式为y=0.4762x-1.1316,相关系数R为0.7584,说明该参数为一稳定性参数,主要受有机质总量决定,集中反映了生物制约性.而与湖南张家界样品有机碳含量Ln(Corg)与铂族元素含量∑PGE同步正消长关系不一样,即贵州遵义地区铂族元素总量∑PGE与有机碳含量的相关性表现出的不一致的规律,可以解释为后生期的热事件(印支海西期,Rb-Sr等时线年龄277±37Ma)导致有机质干酪根的高成熟化、大量生过气(C>2%)和石墨化趋势,或者说是芳构化效应改变了源岩有机质而导致了有机质的损耗.     

Geodynamic setting,structure, and composition of continuous trachybasalt-trachyandesite-rhyolite series in the north of Altai-Sayan area: the role of crust-mantle interaction in continental magma formation

The geologic positions and geochemical and isotope parameters of the Ordovician-early Silurian and Early-Middle Devonian continuous volcanic series of the Minusa basin and its mountainous framing are compared. Both series are composed mostly of moderately alkaline rocks with variations in SiO₂ contents from 45 to 77 wt.%. The Ordovician-early Silurian series differs from the Early-Middle Devonian one in lower contents of TiO₂ (< 1.7 wt.%) and Fe₂O_3tot and higher contents of Al₂O₃ in all rock varieties and in the more fractionated REE patterns of trachybasalts. The compositions of both series reflect two simultaneous mechanisms of magma evolution. The main process was fractional crystallization leading to the formation of rocks from trachybasalts to trachyrhyodacites. The accessory mechanism was the contamination of fractionated melts by crustal material, anatectic melting of crust, and mixing of deep-seated magmas with crustal melts. These processes had specifics at each stage and were controlled by the composition of the sources of parental melts. Their geochemical and isotopic parameters (high alkalinity, high contents of lithophile elements, negative anomalies of Nb, Ta, and Ti, and enrichment in radiogenic Sr) point to the interaction of mantle plumes with the lithospheric mantle that was metasomatically transformed during the preceding Vendian-early Cambrian subduction processes.     

Carbon and Noble Gas Isotopes in the Tengchong Volcanic Geothermal Area, Yunnan, Southwestern China

Carbon and noble gas isotope analyses are reported for bubbling gas samples from the Tengchong volcanic geothermal area near the Indo-Eurasian suture zone. All samples contain a resolvable component of mantle-derived 3He. Occurrence of mantle-derived 3He coincides with surface volcanism. However, 3He occurs over a larger geographic areathan do surface volcanics. δ13C values for CO2 and CH4 vary from -33.4‰ to 1.6 ‰ and from -52.8‰ to -2.8‰, respectively. He and C isotope systematics indicate that CO2 and CH4 in the CO2-rich gases originated predominantly from magmatic component mixed with crustal CO2 produced from carbonate. However, breakdown of organic matter and near-surface processes accounts for the CH4 and CO2 in N2-rich gases. 3He/4He ratio distribution pattern suggests that mantle-derived He and heat sources of high-temperature system in central Tengchong originate from a hidden magma reservoir at subsurface. CO2-rich gases with the highest 3He/4He ratio (5.2 Ra) may be representative of the     

地震平点技术与应用进展

利用平点技术进行地震勘探虽然经历了50多年的发展历程,但是国内外尚缺乏对平点技术与应用进展的系统分析。通过对平点技术的基本原理、平点识别方法、平点技术应用进展及应用"陷阱"进行全面的调研与梳理认为,不同流体纵波阻抗的差异是产生平点反射的基本条件;水平反射与AVO振幅异常突变处吻合并且具有统一的深度值,是烃类平点最重要的判别标准;通过地震反射特征,结合共等值线抽道集叠加技术和基于信号强化处理的平点增强技术等,可以提高平点的识别效果;地震资料产生的假象、非储层因素导致的平点假象以及流体界面由于速度和压力的变化都会导致平点"陷阱"的产生。研究指出,加强地质与地球物理综合分析,进一步提高地震资料的保真度、信噪比和分辨率,加强与其他烃类检测方法的综合应用及大力发展多波多分量地震技术在平点勘探中的应用是平点技术的发展趋势,未来其应用必然会更加广泛。     

鄂温克旗干旱、洪涝灾害期评定及预测方法

根据鄂温克旗1959—2008年气象历史资料,统一归类,并采用统计预报方法,简要评定预测出鄂温克旗50年来主要气象灾害之一的干旱、洪涝灾害期,为鄂温克旗防范旱涝灾害做参考。     

新型矿井多波多分量地震反射波观测系统的设计

针对DTC-150防爆地质超前探测仪在工程应用中存在的几个问题,提出了研制新型矿井多波多分量地震反射波观测系统的必要性.通过对大量工程预测预报资料的分析,结合煤岩有效地震波频率特性等4个关键技术的研究,得出了煤岩有效地震波频率范围和观测系统的有效布设方式,研制了高速、高精度、多通道数据采集及处理系统,给出了掌子面绕射回波形成的探测盲区和巷道声波的处理方法,提出了掌子面绕射回波与直达波不重叠的条件.新型矿井多波多分量地震反射波观测系统的研制成功为矿井提供了更为准确、更长距离的超前预测预报手段,同时也为煤矿安全生产提供了有力的保证.     

The environmental planning and management approach towards the development and management of the Osun natural spring project,Ibadan, Nigeria

There is a general shortage of potable water in Nigeria, partly through the lack of natural provision and partly because of rapid urban growth that has largely been unplanned. The paper describes the recent redevelopment of a public water facility in a run-down area of Ibadan which is part of the Sustainable Ibadan Project. Despite funding from national and international bodies, the development is strongly based at community level. The local inhabitants feel they have control over their own water supply through their representatives on the various planning and managing committees. This aims to reduce vandalism and to increase pride and involvement in the community. The project is a pilot for other projects around Ibadan, some of which have begun and others are being planned. This paper describes the administrative structures and management principles that have been employed. It forcefully advocates community-based planning and management which respects both the environment and the water-users, and involves a major “bottom-up” element. This revised version was published online in July 2006 with corrections to the Cover Date.     

新疆比勒提地区断裂构造磁异常信息提取及解释

比勒提地区位于新疆西南天山,以该区1：50000高精度磁测数据为基础,采用解析延拓、方向导数等技术手段提取与断裂构造有关的磁异常信息,对区域内构造进行识别,结合标本物性参数统计,对引起磁异常的原因进行分析。对区域磁异常向上延拓及求一阶导数后进行对比,圈定4个特征异常带A1-A4,结合地质资料,识别出4条断裂构造FW1-FW4,FW1和FW2对应喀拉铁克断裂及其次级断裂,FW3为构造动力作用产生的强片理化带,FW4为隐伏断裂,表明高精度磁法测量在本区能有效识别断裂并反映其分布。     

Nonstationary pearl pulsations as a signature of magnetospheric disturbances

We analyse long-lasting (several hours) Pc1 pearl pulsations with decreasing, increasing or constant central frequencies. We show that nonstationary pearl events (those with either decreasing or increasing central frequency) are observed simultaneously with increasing auroral magnetic activity at the nightside magnetosphere while the stationary events (constant central frequency) correspond to quiet magnetic conditions. Events with decreasing central frequency are observed mostly in the late morning and daytime whereas events with increasing central frequency appear either early in the morning or in the afternoon. We explain the diurnal distribution of the nonstationary pearl pulsations in terms of proton drifts depending on magnetic activity, and evaluate the magnetospheric electric field based on the variation of the central frequency of pearl pulsations.