陇县904地区混合岩型铀矿成矿特征的讨论

含铀混合岩大部分位于古陆隆起带边部、ＮＷ向花岗岩外接触带。深大断裂系统在成矿成岩中占有相当重要的地位。燕山期构造和岩浆活化，对原有的构造和矿化进行了强烈改造。在混合岩中发现了两种主要成矿类型，即铀一赤铁矿型和铀一碳酸盐型。     

综合处理办法在城市复杂地段桥桩施工中的应用

在北京市德内大街桥桩施工过程中,不仅遇到交通拥堵．场地狭小．地上地下障碍物等多种不利条件．而且在拟施工的桩位处遇到大量原有河道的加固材料,物品种类之多、数量之大、埋深之厚,实属罕见,施工条件极差、施工难度极高,施工单位最终通过采取多种办法、措施解决了这些难题,圆满的完成了桥桩施工任务。本人认为在旧城复杂地段施工时,综合处理措施具有很大发展空间,值得深入研究发展,在旧城改造的类似工程中具有一定借鉴作用。     

Rare-earth elements in Luochuan loess section,Shaanxi province

TheΣ REE in loesses of different ages in the Luochuan section shows a narrow range of variation, indicating the homogeneity of loessic materials in chemical composition. The REEs in loess are concentrated mainly in silt-sized detrital minerals. Loesses and paleosols of different ages all are relatively enriched in rare-earth elements of the Ce family, and show similar REE distribution patterns. The fractionation among various REEs in the loess is different from that in morainic, marine and lacustrine sediments, but is similar to that in sand samples from deserts in Northwest China. The ratios of Ce/Ce* and Eu/Eu* reflect that the provenance of loessic materials and their accumulating area are all in an oxidation environment with weakly basic mediums under arid or semi-arid climate.     

河北大湾锌矿中硫锰矿与闪锌矿的成因关系

本文研究了产于河北大湾锌矿床中的硫锰矿,探讨了硫锰矿与闪锌矿的成因关系。由实验结果而认为大湾硫锰矿是从深色高锰闪锌矿中出溶而成的。     

Distribution and sequential extraction of some heavy metals in urban soils of Guiyang City,China

Sixty-two soil samples collected from different functional zones of Guiyang were analyzed for total concentrations and sequential extraction of Cr, Cu, Pb, Zn and Cd by ICP spectrometry. The average total concentrations ofCr, Cu, Pb, Zn and Cd in the soils of Guiyang were 92.9, 51.6, 44.1,139.3 and 0.28 mg/kg, respectively. The soils have been polluted by Cr, Cu, Pb, Zn and Cd to some extent in comparison with the background values of Guiyang. Significant differences were recognized in the concentrations of Cr, Cu, Pb, Zn and Cd in different functional zones. As for the sequential extraction, Cr, Cu and Zn were present mainly in the residual fraction, and Pb was present mainly in the oxidizable fraction. The reducible fraction of Cd accounts for 47.5%, and the residual fraction is lowest. The mobility and bioavailability of heavy metals follow the order of Cd〉Pb〉Cu〉Cr〉Zn.     

Sources of dissolved organic carbon in forest soils: evidences from the differences of organic carbon concentration and isotope composition studies

There is considerable discussion and uncertainty in the literature regarding the importance of fresh litter versus older soil organic matter as sources of soil dissolved organic carbon (DOC) in forest floor. In this study, the differences of organic carbon concentration and stable isotope composition were analyzed under different background conditions to identify the origins of DOC in forest soil. The data show that there is no significant difference in SOC content between these collected soil samples (P > 0.05), but the litter-rich surface soils have relatively higher DOC concentration than the litter-lacking (P < 0.01) ones, and the δ ¹³C values of DOC (δ ¹³C_DOC) are closer to δ ¹³C of litter than δ ¹³C values of SOC (δ ¹³C_SOC). In the litter-lacking surface soil samples, the range of δ ¹³C_DOC is between δ ¹³C_SOC and δ ¹³C of dominant plant leaves. These results suggest that DOC mainly derive from litter in the litter-rich surface soil with, and the main path of DOC sources may change with surrounding conditions. In addition, δ ¹³C_SOC and δ ¹³C_DOC become more positive, and the absolute values of Δ (δ ¹³C_DOC − δ ¹³C_SOC) decrease with depth in the soil profiles, which indicate that the percentage of DOC below 5 cm, derived from degradation of humus, may increase with soil depth.     

Dynamic analysis of the infiltration rate of artificial recharge of groundwater: a case study of Wanglong Lake,Pingtung, Taiwan

Although Pingtung plain is an agriculturally developed region, its limited hydrologic conditions have restrained the maximization of its surface water resources. Due to the lack of proper management and sustainable utilization, groundwater has been overdrawn, causing serious land subsidence and seawater intrusion. The present paper presents a pilot study for artificially recharging groundwater using high-infiltration basins. Results of the geometric factor show that the large basin is ca. 6.8 times the size of the small one, with the infiltration volume almost approaching 1 m³/day/m². In the groundwater variation, the MW-2 is located immediately below the infiltration basin; therefore, its water level rises more rapidly than that of MW-3. As for the infiltration volume, results of the experiment used the same basin since 2002, which shows that the volumes gradually decreased from 12,136 to 5,555 m³/day. This is particularly evident in 2005 when volume decrease was at a maximum ca. 2,000 m³/day. Finally, the infiltration rate decreased from 22.76 to 7.15 m/day. The difference in infiltration rate between 2003 and 2005 has a maximum variation from to 15.2 to 10.33 m/day. In 2003, the addition of sand caused the infiltration rate to fall to a minimum ca. 5.3 m/day. By extending the recharge time, the infiltration rate fell gradually similar to those identified from 2005 to 2007.     

新发现的周口店晚更新世洞穴地层及哺乳动物群研究

本文依据新发现的晚更新世洞穴地层剖面，进行了年代学及哺乳动物化石方面的研究。年代学综合测定结果为距今１２～１．９万年，这是周口店地区迄今发现的最为完整的晚更新世洞穴地层剖面，根据堆积物中所含的哺乳动物化石特征，进行了生态、种类方面的研究，建立了一个新的哺乳动物群─—东岭子动物群。     

南沙群岛海区有机碳沉积作用与古生产力估算

根据南沙群岛海区５个沉积柱样和大量表层样的分析资料讨论了有机碳的沉积作用。深海有机碳含量一般为０．２％－１．３％。水柱深度对其分布的控制作用不明显。分析结果发现冰期、间冰期，尤其是本次冰期有机碳含量变化明显，４个柱样晚第四纪的质量堆积速率在末次冰期时最大。有机碳保存的主要控制因素是溶解氧浓度、粘土矿物含量、水柱深度和底栖混合强度，其中溶解氧浓度是最重要因素。底栖有孔虫的相对丰度，如Ｕｖｉｇｅｒｉｎａ和Ｂｕｌｉｍｉ－ｎａ，可用来指示溶解氧和有机碳含量。有机碳含量与海洋生产力关系极为密切，它可用来重建海洋古生产力的长期变化。采用Ｍｌｌｅｒ和Ｓｕｅｓｓ方程以及Ｓａｒｎｔｈｅｉｎ方程的计算结果与目前生产力值结果比较表明，后一种方法因充分考虑了溶解氧浓度和水柱深度而更接近现代值。