用镭-226示踪胶州湾的海底地下水排泄

海底地下水排泄（SGD）是全球水循环的一个组成部分,其输送的溶解物质不仅参与海洋的生物地球化学循环,而且影响近岸海域的生态环境。为了评估胶州湾海底地下水排泄状况,通过建立胶州湾内海水中²²⁶Ra的质量平衡模型来计算海底地下水排泄通量。胶州湾海水中²²⁶Ra的源主要有河流的输入、沉积物扩散输入和地下水的输入,海水系统在稳定状态下,这几种源应该与湾内海水和湾外海水的混合损失达到平衡。除了将地下水输入作为未知项外,对其他源和汇逐个进行量化,计算得知：2011年9-10月胶州湾的海底地下水排泄通量为7.85×10⁶ m³·d^-1;2012年4-5月胶州湾的海底地下水排泄通量为4.72×10⁶ m³·d^-1。在此基础上,对地下水输入胶州湾的营养盐进行了评价。     

采用222Rn示踪胶州湾的海底地下水排泄及营养盐输入

为了量化胶州湾东北海岸带的海底地下水排泄量和评价通过海底地下水排泄输入的营养盐数量,分别于2011年10月和2012年5月在胶州湾北岸东大洋码头附近对海水中的222 Rn进行了48h连续测量.通过构建测量点海水中222 Rn质量平衡模型,计算得到海底地下水排泄速率平均值分别为6.38cm/d和8.29cm/d;实际观测到的海底地下水排泄速率变动较大,其主要控制因素是降水量、潮汐和波浪.根据海底地下水排泄速率,获得地下水输入的DIN(溶解无机氮)为47.0×103 mol/d(2011年10月)和48.6×103 mol/d(2012年5月),可溶性SiO2为15.5×103 mol/d(2011年10月)和17.3×103 mol/d(2012年5月),DIP(溶解性磷酸盐)为0.6×103 mol/d(2012年5月),地下水对胶州湾的营养盐输入具有重要贡献.     

用镭同位素评价九龙江河口区的地下水输入

为评价九龙江河口区的地下水输入量及其输送的营养盐数量,建立了天然存在的镭同位素224Ra和226Ra的质量平衡模型。镭的源项考虑了河流的输入、河流悬浮颗粒的解吸、沉积物再悬浮颗粒的解吸、沉积物扩散输入、涨潮时外海的输入和地下水的输入;镭的汇项考虑了镭的放射性衰变,以及退潮时河口水的输出。根据镭的质量平衡计算,地下水输入的镭通量约占河口区镭总输入通量的41.9%~56.9%,转换成地下水输入量为1.65亿1.83亿m3/d,该地下水输入量是河流径流输入量的4倍多。以陆源地下淡水占总的地下水输入量的10%考虑,计算获得营养盐输入通量分别为461万mol/d(DIN)、22万mol/d(DIP)、694万mol/d(DSi),它们分别约是河流输入营养盐通量的23%(DIN)、28%(DIP)、77%(DSi)。结果表明九龙江河口的地下水输入量及其所输送的营养盐相当可观,所输入的营养盐是海域富营养化的潜在影响因素,在未来的河口环境管理中应引起重视。     

基于~(222)Rn的马莲河下游地下水补给河水空间差异特征研究

河水和地下水转化关系的定量评价是流域水资源量管理和合理利用的基础。在西北内陆马莲河流域下游开展氡同位素示踪,利用河水222Rn通量模型评价了地下水沿河排泄强度。结果表明:地下水222Rn活度高于河水1个数量级,潜流带水222Rn活度受河水、地下水混合作用及沉积物氡释放影响。马莲河下游均为白垩系环河组地下水排泄补给河水,累计排泄量4.5 m3/s,占河流流量的73.2%。排泄强度存在空间变异,上段及下段为地下水强排泄区,中段作用强度较低。模型不确定性主要受地下水端元、潜流带输入及气体逸散系数三个因素控制,222Rn示踪方法在地下水补给河水型地区较为适用。     

用镭同位素评价海水滞留时间及海底地下水排泄

海底地下水排泄(submarine groundwater discharge, SGD)难以直接测量, 镭同位素和氡-222等天然示踪剂使得间接评价SGD通量成为可能.为了评价五缘湾的水体滞留时间和SGD通量, 实测了湾内海水、湾外海水和地下水中224Ra和226Ra的活度, 利用224Ra和226Ra半衰期的差异, 采用224Ra与226Ra的活度比值计算湾内水团的年龄和平均滞留时间, 利用224Ra和226Ra的质量平衡模型计算SGD通量.五缘湾13个站位的水团年龄在0.6~2.4 d之间, 湾顶水团年龄相对较大, 平均海水滞留时间1.4 d.地下水输入五缘湾的224Ra和226Ra通量分别为5.17×106 Bq/d和5.28×106 Bq/d, 将该通量用地下水端元的活度转换成为SGD通量分别是0.21 m3/m2/d(224Ra平衡模型)和0.23 m3/m2/d(226Ra平衡模型), 两种模型的结果较接近, 其平均值0.22 m3/m2/d可作为五缘湾的海底地下水排泄通量.      

长江中游荆江段地下水排泄的量化及其空间差异性分析

地下水与河流的相互作用对于维持河流生态系统的健康十分关键,但是目前对于地下水向湿润地区大型河流排泄过程的定量化研究较为薄弱.针对这一问题,以长江中游荆江段为研究区,通过野外采样和水文气象数据收集,利用222Rn质量平衡模型定量估算长江中游荆江段的地下水排泄,并用EC质量平衡模型及水量平衡模型验证222Rn质量平衡的结果 .结果显示：长江中游荆江段的平均地下水排泄速率为133 mm/d,排泄总量为1.06×108 m3/d,对水量平衡的贡献约为10.99%.其中枝城-沙市段地下水排泄速率最大,监利-螺山段地下水排泄速率最低.含水层富水性和地下水位可能是控制地下水排泄速率的关键因素.本研究对于流域水资源管理具有重要意义,也可为今后长江中游地区水资源的合理开发利用以及生态环境保护提供理论依据.     

用氡-222评价五缘湾的地下水输入

海底地下水排泄(SGD)近年来成为陆-海相互作用的研究热点,地球化学示踪方法是其主要研究手段,尝试用天然示踪剂氡-222评价厦门五缘湾的SGD。为了评价五缘湾SGD的入海通量及其变化,对五缘湾海水中²²²Rn和²²⁶Ra活度、大气中²²²Rn活度、风速、水温和水深进行了连续2 d的测量,对沉积物进行了培养实验用以获得其²²²Rn扩散通量和孔隙水中²²²Rn活度。基于海水中²²²Rn通量的质量平衡,对实测的海水中²²²Rn活度实施了母体支持、涨落潮影响、大气逃逸损失、沉积物扩散输入、混合损失的校正,保守估计SGD输入的²²²Rn通量在0~126.7 Bq/(m²·h)范围内变化,对海水中²²²Rn的平均贡献达54%。以井水和孔隙水中²²²Rn的加权平均值作为SGD端元的代表,获得SGD的输入速率为0~29.3 cm/d,平均输入速率9.3 cm/d。SGD输入速率的动态变化基本围绕12 h的周期波动,是对本海域正规半日潮的具体响应。假设SGD以平均速率在五缘湾海底输入,则五缘湾海底的SGD输入量为1.86×10⁵ m³/d。以陆源地下淡水占SGD输入量的10%考虑,五缘湾的陆源地下淡水输入量约为1.86×10⁴ m³/d。     

氡(222Rn)在地下水-地表水相互作用中的应用研究进展

地下水-地表水相互作用是水资源管理和地表水生态系统保护中重要的一个环节,氡同位素(²²²Rn)由于其在地下水与地表水中含量差异显著、性质保守、检测难度低,广泛运用于地下水-地表水相互作用的研究当中。本文通过总结分析²²²Rn在不同地表水体(海水、河水、湖水等)中的应用,指出刻画地下水氡浓度的异质性是估算地下水排泄的重点和难点。在估算海底地下水排泄(SGD)时,氡的混合损失项估算不确定、海水氡浓度时空变异性、SGD的多组分特征等可能给估算结果带来较大不确定性;在估算河流地下水排泄时难以确定氡的大气逃逸量;研究人员对氡在示踪地表水补给地下水方面的研究程度相对不足。本文从科学研究和实际生产方面,对²²²Rn的研究应用提出以下潜在方向:(1)降低地下水氡空间变异性对估算地下水排泄量的影响;(2)针对不同水体、不同水文条件,准确刻画氡的大气逃逸量;(3)拓展²²²Rn示踪能够解决的科学问题;(4)将氡质量平衡模型计算与不确定分析相结合,实现软件化。     

海底地下水排泄对海洋锶储库的影响

海底地下水排泄（submarine groundwater discharge,SGD）不仅是全球水循环的重要组成部分,也是各种溶解化学物质由陆向海输送的重要而隐蔽通道。本文在分析全球海洋锶来源的基础上,综述了多种岩性含水层条件下SGD锶的地球化学行为及其控制因素,并利用已有的SGD通量和高分辨率全球岩性数据,计算出更为保守和精确的SGD锶通量及同位素组成,确认了SGD是海洋贫放射成因锶的重要来源之一,起到平衡河流输入的富放射成因锶的作用。     

海底地下水排泄对海洋锶储库的影响

海底地下水排泄（ submarine groundwater discharge, SGD）不仅是全球水循环的重要组成部分,也是各种溶解化学物质由陆向海输送的重要而隐蔽通道。笔者等在分析全球海洋锶来源的基础上,综述了多种岩性含水层条件下SGD锶的地球化学行为及其控制因素,并利用已有的SGD通量和高分辨率全球岩性数据,计算出更为保守和精确的SGD锶通量及同位素组成,确认了SGD是海洋贫放射成因锶的重要来源之一,起到平衡河流输入的富放射成因锶的作用。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

正~~     

GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)