Rate and historical change of direct recharge from precipitation constrained by unsaturated zone profiles of chloride and oxygen‐18 in dry river bed of North China Plain

Quantifying of direct recharge derived from precipitation is crucial for assessing sustainability of well‐irrigated agriculture. In the North China Plain, the land use is dominated by groundwater‐irrigated farmland where the direct recharge derived from precipitation and irrigation. To characterize the mean rate and historical variance of direct recharge derived from precipitation, unsaturated zone profiles of chloride and δ¹⁸O in the dry river bed of the Beiyishui River were employed. The results show that archival time scale of the profile covers the duration from 1980 to 2002 (corresponding to depths from 5 to 2 m) which is indicated by matching the δ¹⁸O peaks in the isotope profile with the aridity indexes gained by instrumental records of annual precipitation and annual potential evaporation. Using the chloride mass balance method, the mean rate of the direct recharge corresponding to the archival time scale is estimated to be 3·8 ± 0·8 mm year^?1, which accounts for about 0·7% of the long‐term average annual precipitation. Further, the direct recharge rates vary from 2·1 to 6·8 mm year^?1 since 1980. Despite the subhumid climate, the estimate of recharge rates is in line with other findings in semiarid regions. The low rate of direct recharge is considered as a result of the relative dry climate in recent decades. In dry river bed, unsaturated zone profiles of chloride and δ¹⁸O combined with instrumental records could offer valuable information about the direct recharge derived from precipitation during droughts. Copyright © 2011 John Wiley & Sons, Ltd.     

冀中拗陷古潜山油田水化学研究

冀中拗陷油气田87%的储量产于海相碳酸盐岩古潜山中,在油气生成、运移、集聚和散失的过程中地下水起了重要作用。本文根据50个试样的水化学分析资料,运用对应分析方法对冀中拗陷古潜山油田水进行了分类并初步探讨了水化学成分演化与油气藏形成的关系。     

Oceannographic Chemistry of Calcium Carbonate in the Sea Area at the Pearl River Mouth

Based on the analytical results for 101 samples from 50 survey spots,this paper describes the changes in rations of various components in calcium carbonate from the sea area at the Pearl River mouth with pH.Relations of ∑CO2 with salinity,and Ca concentration with salinity in different parts of the river mouth have been established.The annual throughput of Ca from the Pearl River and the saturation degrees of calcite and aragonite have been calculated.     

Miscellaneous information

Miscellaneous information     

云南新平县双沟蛇绿岩稀土元素地球化学研究

双沟蛇绿岩中,变质橄榄岩的REE分布型式为LREE富集型,可能是富大离子亲石元素(LILE)组分交代造成的。地幔岩部分熔融生成的初始熔体LREE亏损,而辉绿岩和玄武岩则存在LREE亏损和富集两种型式,前者相当于N-MORB,后者相当于E-MORB。推测前者来源于亏损的软流圈地幔,而后者的地幔源区经历过一次富集LREE和LILE的事件。双沟蛇绿岩的REE特征暗示它可能形成于弧后盆地。     

The Partitioning of Tungsten bwtween Aqueous Fluids and Silicate Melts

An experimental study has been carried out to determine the partition coefficients of tungsten between aqueous fluids and granitic melts at 800 °C and 1.5 kb with natural granite as the starting material. The effects of the solutions on the partition coefficients of tungsten show a sequence of P > CO ₃ ²⁻ > B > H₂O. The effects are limited (generallyK _D < 0.3) and the tungsten shows a preferential trend toward the melt over the aqueous fluid. The value ofK _D increases with increasing concentration of phosphorus; theK _D increases first and then reduces with the concentration of CO ₃ ²⁻ when temperature decreases, theK _D between the solution of CO ₃ ²⁻ and the silicate melt increases, and that between the solution of B₄O ₇ ²⁻ and the silicate melt decreases. The partition coefficients of phosphorus and sodium between fluids and silicate melts have been calculated from the concentrations of the elements in the melts. TheK _D value for phosphorus is 0.38 and that for sodium is 0.56. Evidence shows that the elements tend to become richer and richer in the melts.     

当前高压变质作用研究中几个值得注意的动向

高压、超高压变质作用是地学研究的热点，它能很好地反映深部地质作用特征和恢复地质历史演化的过程。当前高压、超高压变质作用研究中有几个值得注意的动向：（１）高压变质作用中流体性状和物理化学特点的研究是解决高压变质作用成因的关键；（２）高压变质矿物流变学研究是揭示变质过程的有效途径；（３）超高压变质岩的发现是８０年代地学领域中的一场“革命”，其动力学模式为探讨大陆动力学开辟了新的思路。文中介绍了产生超高压变质的柯石英榴辉岩亚相组合的六种动力学模式。     

塞北雪（锂—锶—偏硅酸）珍贵天然矿泉水

经勘察评价和国家级评审鉴定，天镇县城关Ｔ＿（６７）井属锂－锶－偏硅酸三项达标的复合型优质饮用天然矿泉水。矿泉水产于近东西向挽近断裂带上，马圈痒地热田边部，地势平坦，环境无污染，交通便利，水质独特，水量丰富，具有综合开发优势，适宜建厂开发。     

大同镇川堡玄武岩区西村锶矿泉水

经省、部两级评审鉴定，大同市镇川堡西村泉为锶－重碳酸－钙镁钠型饮用天然矿泉水。其流量大，允许开采量达３００ｍ￣３／ｄ，水质好，环境美，无污染源，交通便利，具有较大的发展潜力和广阔的开发利用前景。     

大 陆 岩 石 圈 研 究

大陆岩石圈和大洋岩石圈有着深刻的差别，运用板块构造理论和模式研究大陆岩石圈会遇到许多特殊的问题。本文从陆缘演化和多个板块构造旋回叠加两方面做了初步探讨，提出岩浆型被动陆缘是独立的一类古陆缘；在辨认后续板块构造旋回叠加中，新构造成分和格局的确定有重要意义。本文还讨论了汲取大陆地质研究经验，在新的学科水平上重新解释传统大地构造学中一些有用概念的意义。