青河北中深变质岩系时代归属及地质意义

阿尔泰青河地区中深变质岩系时代归属问题一直备受争议,通过1∶5万地质矿产调查,将青河地区中深变质岩系构造演化与同位素资料相结合,首次将青河地区中深变质岩系划为中元古界苏普特岩群,为研究阿尔泰地区中深变质岩系构造演化及时代归属提供依据.     

“井水不犯河水”水文地质学含义初步探讨

利用水化学及同位素水文地质学的方法,对密云水库、潮白河及位于潮白河边的2个地下水分层专门监测井进行取样测试,并结合收集相关资料,从水位、水质及氚、氘、氧-18等同位素方面进行分析研究,对中国古语“井水不犯河水”的水文地质学方面的含义进行了一定的微观层次的分析探讨.得出研究点处潮白河水对50 m外的25 m深的浅井井水有...     

Defining dynamic pelagic habitats in oceanic waters off eastern Australia

Although many species in the pelagic ocean are widespread, they are not randomly distributed. These species may have associations with particular water masses or habitats, but to best understand patterns in the ocean, these habitats must be identified. Previous efforts have produced static or seasonal climatologies, which still represent smearing over habitats. The Eastern Tuna and Billfish Longline Fishery (ETBF) targets a range of high trophic level species in oceanic waters off eastern Australia. In this study, dynamic ocean habitats in the region were identified for each month based on cluster analysis of five oceanographic variables averaged at a monthly time scale and a spatial scale of 0.5° for the period 1995-2006. A total of seven persistent habitats were identified off eastern Australia with intra and interannual variation in size and location, indicating the importance of spatial and temporal variation in the dynamics of the region. The degree to which these dynamic habitats were distinguished was tested using (i) stable isotope analysis of top fish predators caught in the region and (ii) estimates of variation in estimated abundance generated from catch data from the fishery. More precise estimates (measured as lower total CV) of isotopic values from swordfish (Xiphias gladius), yellowfin tuna (Thunnus albacares) and albacore (Thunnus alalunga) were obtained for 4 of 6 isotope comparisons using the dynamic habitat groupings, which indicate that stratifying by pelagic habitat improved precision. Dynamic habitats produced more precise abundance estimates for 7 of 8 large pelagic species examined, with an average reduction in total CV of 19% compared to when abundance was estimated based on static habitat stratification. These findings could be used to guide development of effective monitoring strategies that can distinguish patterns due to environmental variation, and in the longer term, climate change.     

辽吉裂谷区铅锌金矿床S、Pb同位素组成特征及其地质意义

辽吉裂谷区发育有众多大中型铅锌、金等多金属矿床,本文选择该地区的青城子榛子沟铅锌矿、白云金矿、五龙金矿、荒沟山铅锌矿和临江金矿作为研究对象,开展其矿石S、Pb同位素分析及其地质意义研究.数据显示榛子沟脉状铅锌矿δ34SCDT值介于-10.3‰～6.8‰之间,白云金矿δ34SCDT值介于-7.7‰～1.9‰之间,五龙金矿δ34 SCDT值介于0.8‰～3.6‰之间,荒沟山铅锌矿δ34 SCDT值介于6.7‰～17.8‰之间,临江金矿δ34 SCDT值介于0.7‰～1.5‰之间.研究区铅锌金矿床的矿石硫同位素主要有两种来源,其一来自于早期火山喷流沉积而成的地层硫,如青城子榛子沟层状铅矿矿体和荒沟山层状铅锌矿;另一类为后期岩浆硫,如青城子榛子沟脉状铅锌矿、白云金矿、五龙金矿以及临江金矿,此类岩浆硫形成过程中,对早期地层硫进行了混染.辽吉裂谷区典型多金属矿床矿石铅同位素值变化较大,206 pb/204 Pb值介于15.72～24.02,207pb/204 Pb值介于15.32～16.43,208pb/204 Pb值介于34.96～39.79,不同的矿床其比值具有不同特点.研究区铅同位素μ值相对集中且较大,显示铅源具有上地壳物质特征,但均受到了不同铅源的混合.榛子沟铅锌矿脉状矿体矿石铅和岩体铅均为混合铅源,矿石铅为上地壳与地幔的混合源铅,而岩体铅则是造山带铅与上地壳的混合源铅;白云金矿床矿石铅为造山带铅,而其岩体铅为上地壳与地幔的混合源铅;五龙金矿的铅同位素主要来源于元古宙造山带铅,同时又有幔源铅的混合;荒沟山铅锌矿矿石铅一组为正常铅,微偏钍铅,来源于统一矿源层,另外一组铅为放射成因铅,即铀铅,而临江金矿矿石铅属于放射成因铅.     

激光剥蚀等离子质谱微区分析在固体地球科学中的应用进展

当前分析化学技术正向着痕量微区方向发展。这使得我们能够用更小更少的样品直接得到更多的地球化学信息。在诸多微区测试技术中,激光剥蚀等离子质谱（LA-ICPMS）技术发展最快。其地质应用较广,激光探针等离子体质谱能够进行固体样品的微区微量元素和同位素的分析,具有灵敏度高、简便、快速的特点,同样具有在同位素定年上的潜力。近年来又研制出激光剥蚀多道接收等离子质谱（LA-MC-ICPMS）仪,使得微区同位素分析开始了新的革命。而多种微区技术综合应用为近几年分析地球化学新的趋势。     

The application of lead isotope ratios in the Antarctic macroalga Iridaea cordata as a contaminant monitoring tool

Lead (Pb) isotope ratios were measured in the marine macroalga Iridaea cordata collected from four locations in the Windmill Islands, East Antarctica. Based on the masses of thalli collected, samples analysed in this study were likely to be a mixture of one and two year old thalli. For a sample of thalli of various ages (<12 months to 2 years old) from the same site there was no apparent variation in Pb concentration or Pb isotope ratio with thallus mass/age, indicating that contaminant sources had been constant over the lifetime of the thalli sampled. I.cordata samples close to the Thala Valley waste disposal site (Brown Bay Inner) near the Australian Station, Casey, displayed isotopic signatures (²⁰⁸Pb/²⁰⁴Pb 35.99; ²⁰⁶Pb/²⁰⁷Pb 1.066; n = 3; average values shown) trending towards that possessed by major Australian Pb sources (Broken Hill and Mt Isa, ²⁰⁸Pb/²⁰⁴Pb 35.60; ²⁰⁶Pb/²⁰⁷Pb 1.041) suggesting that these samples had been exposed to anthropogenic Pb originating from the Thala Valley waste disposal site. Material collected hundreds of metres from the tip location at Brown Bay Outer had isotopic values (²⁰⁸Pb/²⁰⁴Pb 36.32; ²⁰⁶Pb/²⁰⁷Pb 1.088; n = 10) intermediate between Brown Bay Inner and sites further from the contaminant source at Sparkes Bay and Wilkes (²⁰⁸Pb/²⁰⁴Pb 36.46; ²⁰⁶Pb/²⁰⁷Pb 1.094; n = 4) showing that contaminant transport was predominantly restricted to Brown Bay Inner. This study demonstrates that the isotope ratios of Pb in marine macroalgae can provide valuable information as to the origin and extent of heavy metal flux in a marine environment.     

Noble gas tracers for characterisation of flow dynamics and origin of groundwater: A case study in Switzerland

The Grenchen aquifer system in the Swiss Plateau was extensively investigated in order to determine the extent of groundwater contamination and to assess the natural attenuation capacity. Environmental tracer data were applied to estimate groundwater travel times, mixing ratios, and evaluate groundwater origin. Recharge is basically possible in two distinct topographical areas, the immediate vicinity of the town of Grenchen and the elevated plateau of the first Jura Mountain ridge. Groundwater dating was performed with the ³H/³He dating method and supplemented by ⁸⁵Kr measurements. Stable isotope data (δ¹⁸O, δ²H) and dissolved noble gas concentrations allow the determination of the recharge temperature, which is correlated to the recharge elevation. Noble gas temperatures (NGT) decrease in the direction of groundwater flow and range from 10 to 13 °C in the upstream area of the town to 7–9 °C in the downstream river plain. This trend could suggest the admixture of water from the underlying limestone aquifer recharged under cooler infiltration conditions, e.g. at higher recharge elevations. However, it is shown in this study that the difference in NGT does not require such a recharge. Rather, increasing air temperatures over the last 40 years and the urban heat island effect could possibly explain most of the observed temperature shift. Furthermore, it is concluded that the downstream river plain is hydrologically disconnected from the upstream town area. Consequently most water from the town area is drained by the creek Witibach and recharge in the river plain is higher than previously assumed.     

内蒙桌子山地区凝结水对岩溶地下水补给的探讨

内蒙古桌子山区为西北干旱地区,平均年降水量不足200mm。区内中、下奥陶统碳酸盐岩中岩溶水是当地重要供水水源。该区岩溶地下水氢氧同位素关系图表明,其样点基本分布在当地雨水线左上方,存在明显的反向“氧漂移”现象,这种现象在作者所见到我国北方多数岩溶泉域岩溶地下水的同位素分布是唯一的。通过本区特定的气候、水文地质条件以及自然条件分析认为,本区岩溶地下水中可能存在凝结水的补给,这一观点在2004年8月30日清晨的露水同位素取样分析后得到了进一步支持。      

Determination of the origin of the Helvadere drinking springs by means of hydrochemical and isotopic techniques, Aksaray, Central Anatolia, Turkey

The main aquifer of the Helvadere springs that emerges on the strike-slip of the Hasanda?? fault set alongside the Tuzgölü (salt lake) fault zone, and trends in a NW–SE direction of Aksaray city, in the western part of Central Anatolia, is the exposed rocks of Hasanda?? which are volcanics that have distinct hydrogeological properties. The meteoric origin of the spring waters is deduced from hydrochemical and environmental isotope (¹⁸O, ²H, ³H) studies. The springs have high discharge (Q>100?l/s) and low ion concentrations because of fast circulation along the groundwater flow path in the aquifer. Furthermore, because it has Ca-Na-Mg-HCO₃ hydrochemical facies, it conforms to high standards of drinking and irrigation water.