Response of groundwater chemistry to water deliveries in the lower reaches of Tarim River,Northwest China

In this paper, we analysed the monitored data from nine groundwater-monitoring transects in the lower reaches of Tarim River during the five times of stream water deliveries to the river transect where the stream flow ceased. The results showed that the groundwater depth in the lower reaches of Tarim River rose from −9.30 m before the conveyances to −8.17 and −6.50 m after the first and second conveyances, −5.81 and −6.00 m after the third and fourth the conveyance, and −4.73 m after the fifth. The horizontal extent of groundwater recharge was gradually enlarged along both sides of the channel of conveyance, i.e., from 250 m in width after the first conveyance to 1,050 m away from the channel after the fourth delivery. With the rising groundwater level, the concentrations of major anions Cl⁻, SO₄²⁻ and cations Ca²⁺, Mg²⁺, Na⁺, as well as total dissolved solids (TDS) in groundwater underwent a significant change. The spatial variations in groundwater chemistry indicated that the groundwater chemistry at the transect near Daxihaizi Reservoir changed earlier than that farther from it. In the same transect, the chemical variations were earlier in the monitoring well close to watercourse than that farther away from the stream. In general, the concentration of the major ions and TDS at each monitoring well increased remarkably when the water delivery started, and decreased with the continued water delivery, and then increased once again at the end of the study period. Hence, the whole study period may be divided into three stages: the initial stage, the intermediate stage and the later stage. According to the three stages of groundwater chemistry reaction to water delivery and the relationships between groundwater chemical properties and groundwater depths, we educe that under the situation of water delivery, the optimum groundwater depth in the lower reaches of the Tarim River should be −5 m.     

海洋湍流的测量及相关分析

对海洋湍流速度脉动的一维概率密度作了测量，并把测量结果与高 斯分布进行了比较。比较的结果表明，一个接近于高斯分布而另一个却差别较 大。计算到直至五阶湍流相关函数并与网格湍流进行了比较，结果都表明小时 间间隔中测量结果与网格湍流的结果近似一致，而大时间间隔中却相差很大。 以上结论说明了较长的测量时间的必要性。     

渤海湾沿岸泥炭沼泽形成机制与时空分布

渤海湾沿岸的海陆过渡带，优越的水文地理环境有利于泥炭沼泽的形成与发育。海洋海退导致的海岸线变迁，是控制泥炭沼泽发育时间和空间分布的主导因素。间冰期和冰后期的海面上升期间，自海向陆发育了海侵基底泥炭；中全新世高海面期，在山前扇缘洼地和沟谷有泥炭沼泽发育；晚全新世海面下降期，泥炭沼泽主要发育在沿岸的海湾、泻湖、三角洲汊河间洼地及平原上的河滩、阶地、古河道等地。     

黄河河口演变(Ⅰ) --(一)河口水文特征

本文利用20世纪后半个世纪的完整实测资料，研究了河口径流量与输沙量的变化，自50年代至90年代呈明显递减。对黄河口的水文特征：水情、沙情、断流、离子流量、滨海潮汐、潮流、余流、温、盐度分布、风暴潮、拦门沙与盐水楔等作出定性和定量的论述。对断流的危害、成因及缓解对策作出分析。河口淤积、延伸、改道对黄河下游的影响也作出时空上的定量分析。对1855年以来近代黄河三角洲海岸线变化，作出了定量研究。     

Variability of organic δC and C/N in the Mersey Estuary, U.K. and its implications for sea-level reconstruction studies

Microfossil analysis (e.g. diatoms, foraminifera and pollen) represents the cornerstone of Holocene relative sea-level (RSL) reconstruction because their distribution in the contemporary inter-tidal zone is principally controlled by ground elevation within the tidal frame. A combination of poor microfossil preservation and a limited range in the sediment record may severely restrict the accuracy of resulting RSL reconstructions. Organic δ¹³C and C/N analysis of inter-tidal sediments have shown some potential as coastal palaeoenvironmental proxies. Here we assess their viability for reconstructing RSL change by examining patterns of organic δ¹³C and C/N values in a modern estuarine environment. δ¹³C and C/N analysis of bulk organic inter-tidal sediments and vegetation, as well as suspended and bedload organic sediments of the Mersey Estuary, U.K., demonstrate that the two main sources of organic carbon to surface saltmarsh sediments (terrestrial vegetation and tidal-derived particulate organic matter) have distinctive δ¹³C and C/N signatures. The resulting relationship between ground elevation within the tidal frame and surface sediment δ¹³C and C/N is unaffected by decompositional changes. The potential of this technique for RSL reconstruction is demonstrated by the analysis of part of an early Holocene sediment core from the Mersey Estuary. Organic δ¹³C and C/N analysis is less time consuming than microfossil analysis and is likely to provide continuous records of RSL change.     

叠前时间偏移方法在煤田勘探中的应用

根据克希霍夫积分法的原理,介绍了叠前时间偏移的方法特点,实现过程,以及对地震资料的要求,依托国家重大产业技术专项“西部煤炭资源高精度三维地震勘探”工程,对“青海省鱼卡煤田四井田高精度三维地震勘探”资料进行叠前时间偏移,结果表明其能较好地解决成像质量差、能量聚焦不明显、绕射波收敛不理想等方面的难题。通过与叠后时间偏移对比,对于大倾角地层、断块小且多的破碎带、陡倾角不对称向斜等地质问题,其叠前时间偏移剖面成像质量都有明显的提高,反映的构造关系更加清晰,同相轴连续性增强。总结该方法在多个矿区的推广经验．认为合理的观测系统、较高的资料信噪比,准确的测量资料及较高的中表层速度调查精度是做好叠前时间偏移的前提。     

坡地农林复合系统的结构类型与效益分析─以长江三峡库区坡地农业为例

本义认为现代术语的农林复合系统来源于生产实践,体现了农业与林业的有机结合、品种生态和经济的有机结合、产品多样化以及管理科学化4个方面相统一的特点。文章在分析三峡库区农林复合系统的类型结构基础上,提出了农林复合系统可以进行层次结构划分的观点。最后,以典型案例研究方法入手,对1种农林结构类型进行效益分析,结果表明,采用植物篱农林复合坡地系统,是现阶段生产力水平下实现坡地生态经济协调发展的有效途径,值得广泛推广。     

指示红土型金矿表征的遥感地质特征

红土风化壳中铁、锰质和粘土等矿物的含量高，存在大量的Ｆｅ３＋、Ｆｅ２＋、Ｍｎ２＋、Ｈ２Ｏ、（ＯＨ）１－、ＣＯ２３等离子，而这些离子团的含量决定了红土风化壳的发射波谱性状，应用ＴＭ波段对这些离子团的探测能力，就有可能识别到红土风化壳及与红土型金矿有关的地物目标。湘南地区的ＴＭ数据处理，表明了与已知红土型金矿对应的“ＫＬ特征标志色块”可作为红土型金矿成矿预测的最佳标志。     

北淮阳金寨—苏仙石地区中生代花岗岩类岩石学及地球化学特征

位于大别山北麓的北淮阳金寨—苏仙石地区广泛发育花岗岩类侵入岩，同位素年龄为１４０～９７Ｍａ，时代属Ｊ３—Ｋ１。根据侵入岩的地质、岩石学和岩石地球化学特征，将本区侵入岩划分为３个超单元（包括１０个单元）和３个独立单元，分属中性岩和酸性岩两大类，岩石类型有闪长岩、二长岩和花岗岩等。根据岩石化学的判别结果，侵入岩均属亚碱性系列中的钙碱性岩石，并属于普通型和钾质型