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应用天然^32Si测定地下水年龄的新方法——切伦科夫计数法 总被引：2，自引：0，他引：2
^32Si是放射性同位素，它衰变时发射低量（≈0.1MeV)的β－－射线（电子）并生成子体^32P。^32P是一个常用的放射性同位素，衰变时发射高能量（1.7MeV）的β－－射线，半衰期为14.3d，容易测量，因此使^32Si的放射性测量变得较为方便。^32Si和^32P在2－3个月内可达到放射性平衡。^32P的放射性通常用切伦科夫计数法测量。应用^32Si作为示踪剂测定地下水年龄范围为50-1000a，大约需要200mg Si。用Fe(OH)3共沉淀法从天然水中提取SiO2回收率可达60％－95％，然后提取^32P。将H3PO4溶液和TritonX-100混合制备计数溶液，用液体闪烁计数法测量^32P的方向性，最后用公式计算^32Si的放射性浓度。 相似文献
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河北山前平原地下水^32Si年龄初探 总被引：6，自引：3，他引：3
＾３２Ｓｉ是放射性同位素,半衰期约１４０ａ可以测定５０～１０００ａ地下水的年龄,本文用Ｆｅ（ＯＨ）３共沉淀法从天然水中提取ＳｉＯ２回收率可达３０％～９８％,然后提取和纯化＾３２Ｐ,将Ｈ３ＰＯ４溶液和Ｐｉｃｏ－ｆｌｏｕｒ＾ＴＭＬＬＴ混合制备计数溶液,用液体闪烁计数法测量中＾３２Ｐ的放射性,本底计数为４．８０ｃｐｈ,仪器效率为４５．３４％,然后用公式计算样品的＾３２Ｓｉ放射性浓度和地下水的＾３２Ｓｉ年 相似文献
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地下水年龄是重要的水文地质学参数,可以指示地下水的循环时间和更新能力。常用环境同位素测定地下水年龄,但不同的环境同位素由于半衰期不同导致定年范围有限,50～1 000 a成为地下水定年的“短板”。然而,50～1 000 a是近代人类活动频繁的时期,地下水资源、水环境和水气候记录档案等研究都需要年龄标尺。32Si可以用来确定50～1 000 a地下水的年龄,但是由于其复杂且费时费力的前处理和测试限制了32Si定年的应用。32Si衰变生成子同位素32P,32Si和32P在3个月内会达到放射性平衡,放射性活度达到一致。天然状态下50～1 000 a地下水中的32Si与32P一直处于放射性平衡状态,所以直接富集地下水中的32P可以用于50～1 000 a地下水的年龄测定。地下水中32P的富集采用氢氧化镁共沉淀法,方便快捷。因此,放射性成因32P有望解决50... 相似文献
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从黑河流域地下水年龄论其资源属性 总被引：16，自引：1，他引：16
地下水资源的可持续性是当前干旱区流域水资源管理的首要问题之一 ,我国西北内陆干旱区地下水的可持续开发必须首先要了解地下水系统的更新能力 ,地下水的放射性同位素测年可以提供系统循环时间和更新能力的重要信息。本文利用地下水中放射性氚 (3H )和碳 (1 4C)测年方法 ,计算黑河流域地下水的年龄 ,进而讨论地下水的更新性。结果表明 :潜水年龄多数小于 5 0 a,具有可再生的资源的属性 ,其中山前戈壁带和张掖盆地细土平原潜水地下水年龄小于 4 0 a,为 196 3年以来补给。酒泉东盆地排泄区承压含水层中地下水的年龄为 2 338～5 5 6 9a,额济纳附近的深层承压含水层中 ,地下水的年龄为 5 4 86～ 86 30 a,地下水资源更新性较差。但是张掖盆地河流附近深层承压地下水年龄小于 5 0 a,具有一定的更新性。上述认识不仅对黑河流域水资源管理和生态环境建设具有重要意义 ,而且对西北类似的内流盆地的地下水系统的研究有着借鉴意义 相似文献
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北京市永定河流域地下水^14C年龄的初步分析 总被引：1，自引：0，他引：1
应用同位素方法初步分析北京郊区永定河流域地下水的演化特点。沿永定河冲洪积扇地下水流动方向布置取样剖面，共有取样点14个，对采集的水样进行^14C和氚含量分析，并确定地下水同位素年龄。浅层孔隙水的^14C年龄的变化范围为730～4900a，深层孔隙水为13420-22480a；^14C年龄在垂直方向上由浅部至深部逐渐增大，最大变化幅度为从3010a增至22480a；浅层孔隙水的氚含量都在14．99～30．56TU之间，深层孔隙水大部分在0．51～4．71TU之间。运用地下水^14C和氚年龄在垂向和水平方向变化的结果，验证了地下水的流向并计算了地下水的流速变化范围为5．02～62．63m／a，从山前至平原浅层地下水径流速度逐渐变小，反映了地下水水平径流强度逐渐减弱，地下水交替逐渐变差，浅层孔隙水以垂向交替为主，深层孔隙水以水平径流为主。 相似文献
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＾３２Ｓｉ是宇宙成因的放射性同位素，其半衰期约为２００ａ，应用＾３２Ｓｉ作为示踪剂测定地下水年龄的范围为５０－１０００ａ。本文介绍了应用Ｆ ｅ（ＯＨ）３共沉法从天然水中提取ＳｉＯ２的制备方法。 相似文献
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用天然水溶液中２３４Ｕ与２３８Ｕ之间的放射性不平衡研究的方法，对鲁南两城地区３０组水样地表水和地下水铀同位素组分进行了实测。结果表明，本区地下水有三个来源：深部喀斯特岩溶水、浅部孔隙水和地表水。水的铀同位素组分稳定，并应用混合比例计算了地下水资源量，其结果与常规方法计算结果完全一致。 相似文献
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利用环境同位素研究地下水年龄对区域地下水资源评价提供可靠依据。本文以陡河流域为例,通过采集大量地下水中的环境同位素样品,测试水中氚、CFCs和14C含量,分别计算地下水年龄,评价地下水的可更新能力。研究结果表明:Q4含水层受井孔利用情况平均滞留时间存在显著差异;Q3含水层地下水年龄最广,从70年以前的老水到新水不等;Q2含水层主要为生活供水和工业开采层,远离河岸带地下水年龄10~70年;远离河岸带Q1含水层地下水为冷湿气候下补给;灌区地下水浇灌过程中与大气接触发生空气-水平衡,使得CFCs不适合于灌区地下水年龄计算。 相似文献
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河北平原第四系深层地下水36Cl同位素年龄的研究 总被引：10，自引：0，他引：10
为研究河北平原第四系深层地下水的年龄，应用加速器质谱计对河北平原深层地下水样品的N(^36Cl)/N(Cl)进行了测定，计算了其年龄，并与地下水动力学年龄进行了对比研究。结果表明，河北冲洪积平原山前地带保定市第四系第三和第四含水组的地下水年龄皆很小，为近期补给的地下水。中部地带保定地区东部和沧州地区西部的第三含水组地下水年龄皆小于5万a，第四含水组地下水的年龄可能大于10万a。边缘地带沧州市和青县第三含水组地下水年龄为8－9万a左右，东光县为26万a左右；沧州市第四含水组地下水年龄为33万a左右，东光县为77万a左右。 相似文献
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Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
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. 相似文献
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Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
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. 相似文献
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The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
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. 相似文献
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Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozac&#x;h Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
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). 相似文献
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正20141520 Bo Ying(Key Laboratory of Metallogeny and Mineral Assessment,MLR,Beijing 100037,China);Liu Chenglin Saline Spring Hydrochemical Characteristics and Indicators for Potassium Exploration in Southwestern and Northern Tarim Basin,Xinjiang(Acta Geoscientica Sinica,ISSN1006-3021,CN11-3474/P,34(5),2013,p.594-602,5 illus.,3 tables,28 refs.) 相似文献
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正20141243Chen Ge(Hangzhou Research Institute of Petroleum Geology,PetroChina,Hangzhou 310023,China);Si Chunsong Study on Sedimentary Numerical Simulation Method of Fan Delta Sand Body(Journal of Geology, 相似文献
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正20142599Chen Sanming(Guangxi Key Laboratory of Concealed Deposits Exploration,Guilin University of Technology,Guilin541004,China);He Yuzhou Block Model and Reserves Estimation of Panzhihua Iron Deposit Based on 3D Geological Modeling(Journal of Guilin University of Technology,ISSN1674-9057,CN45-1375/N,33(4),2013,p.610-615,9illus.,1table,15refs.) 相似文献
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正20140594 Bai Daoyuan(Hunan Institute of Geology Survey,Changsha 410016,China);Zhong Xiang Faults in the Jingzhou Basin and Their Tectonic Settings(Geotectonica et Metallogenia,ISSN1001-1552,CN44-1595/P,37(2),2013,p.173-183,6illus.,59refs.)Key words:basin evolution,tectonic setting,South China In the Upper Paleozoic and Jurassic se- 相似文献
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正20141912Cao Hui(State Key Laboratory for Continental Tectonics and Dynamics,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China)Gravitational Collapse and Folding during Orogenesis:A Comparative Study of FIA Trends and Fold Axial Plane Traces(Geology in China,ISSN1000-3657,CN11-1167/P,40(6),2013,p.1818-1828,9illus.,35refs.,with 相似文献