西昌市尔乌泉域泉水水文地球化学特征及成因

泉和泉群是川西南乡村居民首要的生活水源,对本区泉水水文地球化学特征及成因的研究具有重要的科学价值和指导意义。以尔乌泉域泉水和地表水为研究对象,通过分析泉水和地表水常规水化学组分、氢氧同位素和氚同位素,探讨了该泉域泉水水文地球化学特征及成因。结果显示:尔乌泉域泉水为中偏碱性低矿化水,其水化学类型为HCO3—Ca·Mg和HCO3·SO4—Ca·Mg型水。地表水因受泉水补给影响具有与泉水相似的组分特征。氢氧同位素分析显示尔乌泉水和地表水补给来源为大气降水,且未发生氧同位素漂移。氚同位素进一步确定泉水为非现代水,地下水经历较长的径流时间。受断裂带和褶皱构造的影响,入渗补给的大气降水与碎屑岩中碳酸盐岩、石膏等矿物发生水岩相互作用,后与第四系黏土物质发生阳离子交换反应,致使泉水水化学组分以Ca2+、Mg2+、HCO-3和SO2-4为主。此外,居民生活污水的排放和化学肥料的施用也对泉水中Na+和SO2-4组分产生影响。     

华北平原地下水年龄校正

地下水14C年龄一般指地下水和土壤CO2隔绝至今的年代.地下水测年在地下水水文学中占有特殊的位置,地下水测年可以用来确定补给区,估算地下水流速度、流量、补给速率、水力传导系数和有效孔L隙度,而且年龄数据还可以用来完善地下水流模型.本研究选择华北平原为重点研究区,利用地下水中的同位素和化学组分的测试结果,应用水文地球化学及同位素水文学等相关知识,通过六种传统模型和反向质量平衡模型(NETPATH)对华北平原地下水年龄进行校正.根据年龄校正结果,分析了深层地下水的年龄变化特点,确定了水流路径上发生的水文地球化     

黔西北裸露岩溶地区水文地球化学特征对土地利用方式的响应研究

为了探讨不同土地利用方式下的水文地球化学特征与地下水循环演化的关系,文章选取贵州省毕节市典型农业区的农田、林地、草地灌木和建筑用地等四类土地利用方式,通过区域地质调查、遥感解译、水化学分析和图解方法,研究裸露岩溶地区其对地下水水化学组分的影响。结果表明:这四类土地利用区域地下水主要组分的浓度和主要矿物的饱和指数都呈差异性。此外,土壤易溶盐组分也随土地利用类型发生改变。并且发现,绝大多数样品中,土壤易溶盐组分浓度高于地下水中相同的组分。因此,降雨入渗补给条件下淋滤作用可导致土壤中易溶盐组分进入地下水中,进而影响地下水化学组分浓度的演化趋势。研究区域地下水均以HCO3-Ca型,HCO3-Ca-Mg型和HCO3-SO4-Ca型水为主,但是,受自然地理因素和人类活动的影响,地下水组分和水化学类型在不同土地利用类型区域中存在差异性。基于本研究建立了地下水演化的两种概念模型。      

四川鲜水河-安宁河断裂带温泉氢氧稳定同位素特征

温泉地下水同位素特征对确定断裂带地下水来源、循环过程和断裂带活动性至关重要。为了确定青藏高原东缘温泉的地下水同位素特征和流体来源本研究采集了鲜水河-安宁河断裂带上温泉水、冷泉水、河流和积雪融水等样品,进行了氢氧稳定同位素和水化学组分测定,并进行了同位素特征的对比研究。分析结果表明,温泉水体δ¹⁸O变化范围为-19.04%~-12.71‰,平均值为-16.42‰;δ²H变化范围为-144.07‰~-88.63‰,平均值为-122.37‰。河水的δ¹⁸O变化范围为-15.90‰~-10.85‰,平均值为-13.86‰;δ²H变化范围为-118.21‰~-71.12‰,平均值为-98.99‰。康定冷泉δ¹⁸O和δ²H分别为-13.66‰和-106.74‰。道孚积雪融水的δ¹⁸O和δ²H分别为-10.27‰和-65.41‰。不同类型水体样品氢氧稳定同位素组成主要分布在全球和区域大气降水线上表明了大气降水成因,缺少明显的氧同位素漂移特征。不同类型水体同位素值差异较大显示出温泉与河水、积雪融水之间补给来源的不一致性。温泉同位素值具有明显的同位素高程效应,鲜水河-安宁河断裂带上氧同位素高程效应为-0.23‰/100m,氢同位素高程效应为-1.95‰/100m。温泉氧同位素漂移与相关离子比值、Na-K-Mg三角图、Li和Sr元素等指标表明研究区域大部分温泉的水岩作用强度弱。氢氧稳定同位素特征、水岩作用特征和循环深度揭示出温泉的成因为远距离大气降水运移补给地下水,地下水在地下热储层加热后通过断裂上升到地表形成温泉,这为认识青藏高原东缘地热水循环、断裂带活动性与演化特征提供了依据。     

江汉平原地下水化学特征及水流系统分析

江汉平原水质性缺水问题日益突出,识别江汉平原地下水流系统分布模式,对地下水资源的合理利用与保护具有重要意义。选取江汉平原典型区域,综合水文地质条件、水动力场及水化学同位素指标深入分析地下水补给过程、水岩作用及滞留时间。得出由于碳酸盐岩的溶解,研究区的地下水化学类型属于HCO_3-Ca·(Mg)型。地下水中典型离子随深度增加逐渐降低,同位素随深度增加逐渐偏负,表现出地下水流系统呈局部与区域水流系统的特点,系统深度界限在10～20 m。独立而复杂的局部水流系统在平枯水期地下水向河渠地表水排泄。根据~3H的含量,局部水流为现代水,水循环交替迅速。受地形控制,中深层地下水总体由西和西北向东和东南径流,汇入汉江和长江,为区域水流系统。由于补给源的高程效应,区域水流的~(18)O值存在明显分区,指示不同的补给来源与水流路径。山前丘陵区基本为现代水,向平原腹地纵深至汉江和长江排泄区,地下水年龄在几百年至6 000 a不等,水循环交替缓慢。研究发现江汉平原低洼排泄区存在区域水流的顶托补给,可为原生劣质水的分布与聚集研究提供依据。     

银川盆地水体氢氧稳定同位素特征分析

中国西北部银川盆地干旱少雨,大量的黄河水用于灌溉,灌溉入渗水对地下水循环的参与程度、参与深度研究是进一步解决灌区水环境问题和确定地下水污染来源的关键,需要深入研究。笔者通过氢氧稳定同位素特征分析和氚同位素年龄分析,构建了银川盆地不同水体同位素特征分布关系。结果表明:银川盆地降水和流经的黄河水的氢氧稳定同位素丰度均值都分布在全球雨水线上,降水和黄河水符合全球大气降水来源;深层地下水、浅层地下水及由地下水排泄汇集的排水沟水的氢氧稳定同位素都分布在地下水拟合线上(δD=8.24δ18O+1.08)。这条地下水拟合线与全球雨水线近似平行分布。两线之间的差异指向2种不同水循环的主导过程,即蒸发-混合主导过程和水岩交互-混合主导过程。两种解释对应的灌溉循环量分别占地下水排泄量的44.07%和89.76%,初步认为水岩交互-混合是地下水拟合线分布于全球雨水线下方的主导过程。     

海河流域平原地下水同位素年龄及其水化学区域分布特征

本文从海河流域平原区第四系地下淡水同位素年龄和水化学的区域分布特征的相似性入手 ,初步探讨了地下水形成年龄与其化学组分通过水循环演化过程而建立的关联机制 ,得出地下水1 4 C校正年龄或其水化学组分的区域分布特征中蕴涵着量化描述一个地区地下水循环演化进程和水动学条件信息的新认识。     

锂同位素地球化学在地热流体水岩反应中的应用——以川西现代富锂热泉研究为例

高温流体的化学组成及同位素特征是深部环境信息的重要载体.本文基于锂同位素地球化学方法系统分析了川西现代热泉地热流体的水化学特征、水岩反应过程、补给来源、水岩反应温度及循环深度.研究结果显示,茶洛热泉水化学相类型为HCO3-Na型,与地表水和冷地下水的HCO3-Ca型存在明显区别.利用锂同位素温标估算茶洛热泉的水岩反应体...     

内蒙古鄂尔多斯西北土壤水流动示踪实验及自流井群补给源讨论

降水模拟实验证明,鄂尔多斯北部沙土层单次降水入渗最大深度小于1 m,降水在土壤中受到蒸发后排泄到大气中。实验证实,只有当土壤含水率达到最大田间持水率,吸附在土颗粒表面的薄膜水才能克服电磁引力转化为重力水,在重力的作用下继续下渗。鄂尔多斯北部的年降水量小而蒸发量大,降水入渗土壤不能形成累积效应,无法形成连续下渗的重力水流。同位素示踪分析表明,土壤水主要来源于地下潜水,结合土壤含水率与TDS分析证实,地下水是通过薄膜水与蒸发-凝结方式补给到土壤水中,薄膜水从高温区向低温区流动,对于等温的薄膜水而言,薄膜水从厚层向薄层流动。同位素分析表明,都思兔河流域的河水、泉水、井水、湖泊、土壤水接受相同的外源水补给。鄂尔多斯盆地降水比地表水与地下水明显富集重同位素,不符合补给区降水同位素特征。鄂尔多斯盆地地下水分水岭与基底断裂带重合,据此推断,外源水以深循环方式通过基底断裂带补给鄂尔多斯盆地,在干旱地区形成自流井群。     

基于环境同位素法对衡水湖区域地下水循环演化特征研究

衡水湖位于河北省冀枣衡漏斗区西部。为客观认识该地区地下水的循环模式及人类开发利用对地下水循环的影响,根据环境同位素标记性和计时性特点对其进行分析研究,利用D、18O、T环境同位素方法对冀州市衡水湖一带第四系地下水的循环模式进行研究,初步判定该区域地下水补给运移及地下水的循环演化特征。研究结果表明:该区域地下水划分为两种地下水类型,第Ⅰ含水组为"新水",主要接受降水和地表水的补给;第Ⅱ、Ⅲ含水组为"老水",除接受侧向补给外,还接受上层浅水的越流补给;人工超采地下水改变了地下水循环演化特征以及地下水中D、18O、T的同位素组成,增大了地下水遭受污染的风险。     

基于典型钻孔的江汉平原地下水成因分析

江汉平原地下水需求量日益增加、水质持续恶化,深入探究地下水的成因,对于地下水的合理利用与评价具有重要意义.选取江汉平原腹地YLW01钻孔和汉江附近HJ007钻孔为研究对象,钻探采集原状土柱,提取孔隙水,分析其水化学和氘氧同位素特征.研究表明:YLW01孔中深层砂性土孔隙水为咸水,TDS为1 131~4 013 mg/L,粘性土孔隙水为淡水;HJ007孔孔隙水均为淡水.YLW01孔中深层砂性土孔隙水的高SO₄2-含量（459~2 124 mg/L）,由石膏溶解形成;HJ007孔中深层孔隙水的高NO₃-含量（22~315 mg/L）,由土壤中硝化作用形成.孔隙水化学成分主要受矿物溶解和阳离子交替吸附作用影响,在长江和汉江带作用程度不同.氘氧同位素特征表明孔隙水来源于大气降水,且汉江带浅层地下水受到明显的地表水混合.江汉平原两个钻孔水化学与同位素的差异受长江和汉江影响带河湖相沉积环境、沉积物粒度及矿物组成所控制.      

Correlations between soil gas and seismic activity in the Generalized Haiyuan Fault Zone,north-central China

Radon and mercury concentrations were measured in 10 fault gas profiles in Generalized Haiyuan Fault. This paper aims to predetermine the potential seismic risk in different segments of the fault zone from the perspective of geochemistry. The background value and anomaly threshold were adopted and synthesized using the maximum value method and average method to calculate concentration intensity values of radon and mercury. Fault soil gas mercury and radon concentrations show a decreasing gradient from NW to SE indicating evident segmentation. Higher values are mostly distributed in the Maomao Mountain–Tiger Mountain fault and Jingtai area. Combined with the seismotectonic background of historical and recent earthquakes and the spatial distribution characteristics of b-values, the fault soil gas concentration intensity shows a close correlation with earthquake activity within the fault zone. Concentrations of fault gas are higher and the b-value lower in areas of strong seismic activity, and regions with weak seismic activity correspond to lower fault gas concentrations and higher b-values. It is thus considered that the Jingtai area may be more dangerous than the other areas. This paper could provide vital background information for earthquake prediction in the Generalized Haiyuan Fault Zone.     

Deuterium composition and flow path analysis as additional calibration targets to calibrate groundwater flow simulation in a coastal wetlands system

A conceptual model of the Lake Warden coastal wetlands system, Western Australia, was developed using hydraulic, chemical and stable isotopic data, and formed the basis for a groundwater flow model using the finite element numerical code (FEFLOW). The system to be modeled is complex. The surface water and groundwater within the wetlands system show varying salinity and isotopic composition over short distances and time frames. As a first step, the flow model was calibrated to observed groundwater levels measured since 2001 for both steady state and transient stresses. Particle tracking analysis was conducted to test the source areas of water discharging to the lakes within the wetlands system. The analysis was able to delineate the connectivity between the lakes in the wetland and the flow path. Enrichment of isotopic concentration is evident along a NE–SW transect and the data set provides a means for calibrating a detailed transport model. The study incorporates the varying deuterium composition of the water bodies directly into a transport model and a good match between observed and simulated temporal variations along the transect indicates that the model closely simulated the dynamics of water exchange between the lakes and groundwater within the system.     

Mobility and Transport of Nd Isotopes in the Vadose Zone During Weathering of Granitic Till in a Boreal Forest

There is a broad correlation between the ε_Nd values for rivers (including both the water and the particulate material it carries) and the age of the source terrain. This paper presents Nd isotope distribution data for soil, soil water, groundwater, and stream water samples gathered in a small catchment in northern Sweden. The results show that the release of Nd and Sm from boreal forests into streams and, eventually, into the oceans is more complicated than previously realized. The weathering of till causes changes in both the Nd isotopic composition and Sm/Nd ratios. Both the Sm/Nd ratio and ε_Nd were higher in strongly weathered soils horizons than in less weathered till, since minerals with high Sm/Nd ratios were, on average, more resistant to weathering than those with low Sm/Nd ratios. In contrast to the situation for the main minerals and the major elements, the weathering of rare earth elements (REE) was not restricted to the E-horizon: the measured REE concentrations continued to increase with depth in the C-horizon. In addition, REE released by weathering in the upper parts of the soil profile were partly secondarily retained at deeper levels. Therefore, the dissolved Nd released by weathering in the upper soil horizons was trapped and did not enter the groundwater directly. Rather, the Nd in the groundwater largely originated from weathering within the groundwater zone. However, this was not the only source of Nd in the stream water. The Nd isotope composition and Sm/Nd ratio were determined by the mixing between of Nd and Sm in the groundwater and REE-carrying organic material washed out of the soil profile. The groundwater close to the stream reaches the upper soil horizons during high discharge events such as snowmelts, and organic matter carrying Nd and Sm is washed out of the soils and thus released into the stream. Therefore, the Nd exported from catchment is derived from both the weathering within the groundwater zone, and the organic matter washed out from the soil. If longer timescales with more advanced weathering stages in the groundwater zone are considered, it cannot be ruled out that there will be a shift towards more radiogenic values in the exported Nd. Recorded shifts in the Nd isotopic composition in the ocean may thus not only reflect changed source regions, but also the weathering history of the same source region.     

珠江口盆地HA地区古近系文昌组沉积特征

综合岩心、钻井、测井及地震资料,对珠江口盆地HA古近系文昌组的沉积特征及沉积演化进行了研究。结果表 明：HA古近系文昌组可以识别出5个层序界面,划分为4个三级层序,自下而上分别为SQ1、SQ2、SQ3和SQ4。其中SQ1 主要分布在南部,SQ2和SQ3全区分布,SQ4由于南部构造抬升遭受剥蚀,主要分布在北部H4地区。HA文昌组主要发育辫 状河三角洲相、扇三角洲相、近岸水下扇相及滩坝相。文四段时期,惠州凹陷开始裂陷,物源供给较少,靠近XJ30断裂和 HZ26断裂主要发育扇三角洲沉积,HA转换带主要发育辫状河三角洲;文三段发育时期,盆地快速断陷,水体加深。HA转 换带以大规模的辫状河三角洲沉积为特征,靠近XJ30断裂和HZ26断裂发育扇三角洲沉积,规模相对较小,受波浪不断淘 洗,惠州H4地区发育滩坝沉积;文二段发育时期,南部断裂活动进一步加强,处于强烈活动状态,湖平面继续上升,HA 转换带辫状河三角洲规模变小,陡坡近岸水下扇、扇三角洲连片发育,规模变大;文昌组文一段时期断裂活动减弱,湖水 变浅,物源供应充足,靠近HZ26断裂发育大套扇三角洲,靠近XJ30断裂发育大型浅水三角洲,但后期构造抬升遭受剥 蚀,残留的地层厚度较薄。     

宁夏海原盆地地下水水化学特征及其演化规律

结合宁夏海原盆地已有的地质、水文地质资料,基于水化学、同位素数据分析了研究区的水文地球化学特征。总体上当地的地下水化学场从补给区到径流区到排泄区具有明显的分带性,符合干旱区盆地的水质演化规律;地球化学模拟表明当地水岩相互作用从补给区的以溶滤-混合作用为主逐渐演变成排泄区的以溶滤-蒸发为主。水中的溶解性总固体含量升高主要由岩盐和石膏的溶解引起,第三系岩性及径流条件对地下水水质有很大的影响。同位素特征表明西华山-南华山断裂控制着当地地下水的补给,地下水开采对深层地下水水质的影响尚不明显;在有些地区,由于地下水开采加速了地下水径流,水质有变好的趋势。      

珠江口盆地HA地区古近系文昌组沉积特征

综合岩心、钻井、测井及地震资料，对珠江口盆地HA古近系文昌组的沉积特征及沉积演化进行了研究。结果表 明：HA古近系文昌组可以识别出5个层序界面，划分为4个三级层序，自下而上分别为SQ1、SQ2、SQ3和SQ4。其中SQ1 主要分布在南部，SQ2和SQ3全区分布，SQ4由于南部构造抬升遭受剥蚀，主要分布在北部H4地区。HA文昌组主要发育辫 状河三角洲相、扇三角洲相、近岸水下扇相及滩坝相。文四段时期，惠州凹陷开始裂陷，物源供给较少，靠近XJ30断裂和 HZ26断裂主要发育扇三角洲沉积，HA转换带主要发育辫状河三角洲；文三段发育时期，盆地快速断陷，水体加深。HA转 换带以大规模的辫状河三角洲沉积为特征，靠近XJ30断裂和HZ26断裂发育扇三角洲沉积，规模相对较小，受波浪不断淘 洗，惠州H4地区发育滩坝沉积；文二段发育时期，南部断裂活动进一步加强，处于强烈活动状态，湖平面继续上升，HA 转换带辫状河三角洲规模变小，陡坡近岸水下扇、扇三角洲连片发育，规模变大；文昌组文一段时期断裂活动减弱，湖水 变浅，物源供应充足，靠近HZ26断裂发育大套扇三角洲，靠近XJ30断裂发育大型浅水三角洲，但后期构造抬升遭受剥 蚀，残留的地层厚度较薄。     

Nitrogen as the carrier gas for helium emission along an active fault in NW Taiwan

Variations of He gas concentration are widely applied in studies devoted to the location of faults and to monitor seismic activities. Up to now, its migration mechanism in soil is not fully understood. A systematic soil gas survey across an active fault in NW Taiwan provides the opportunity to closely examine the mechanism of He migration in the fault zone. Significant spatial and temporal correlations observed between soil N₂ and He gas support the hypothesis that N₂ is the probable carrier gas for He emission in the studied area. Based on N₂/Ar ratios and N₂ isotopic results, the excess soil N₂ in this study is considered to be largely derived from ancient atmospheric air which was dissolved in groundwater. Furthermore, observations rule out the possibility of CO₂ being the dominant carrier gas for He in the studied area based on the C and He isotopic compositions and the relationship between concentrations of these gases. At least two soil gas sources, A and B, can be identified in the studied area. Source A is an abiogenic gas source characterized by excess N₂ and He, and very low O₂ and CO₂ content. Source B, on the other hand, is a mixture of biogenic gas and atmospheric air. The development of the fault system is an important factor affecting the degree of mixture between sources A and B. Therefore, variations of soil gas composition, in particular those derived from source A, could be a useful proxy for tracing faults in the area.     

Recharge in northern clime calcareous sandy soils: soil water chemical and carbon-14 evolution

Chemical analyses were performed on soil water extracted from two cores taken from a sandy calcareous soil near Delhi, Ontario. Calcite saturation is attained within the unsaturated zone over short distances and short periods of time, whereas dolomite undersaturation persists to the groundwater table. The progressive dissolution of dolomite by soil water, within the unsaturated zone, after calcite saturation is reached results in calcite supersaturation.Deposition of iron and manganese oxyhydroxide phases occurs at the carbonate leached/unleached zone boundary. This is a result of soil water neutralization due to carbonate dissolution during infiltration but may also reflect the increased rate of oxidation of dissolved ferrous and manganous ions at higher pH's. The role of bacteria in this process has not been investigated.The depth of the carbonate leached/unleached zone boundary in a calcareous soil has important implications for ¹⁴C groundwater dating. The depth of this interface at the study site (?2 m) does not appear to limit ¹⁴C diffusion from the root zone to the depth at which carbonate dissolution occurs. Thus, soil water achieves open system isotopic equilibrium with the soil CO₂ gas phase. It is calculated that in soils with similar physical properties to the study soil but with depths of leaching of 5 m or more, complete ¹⁴C isotopic equilibration of soil water with soil gas would not occur. Soil water, under these conditions would recharge to the groundwater exhibiting some degree of closed system ¹⁴C isotopic evolution.     

Isotopic composition of precipitation and groundwater in Sicily,Italy

The isotopic composition of meteoric water in Sicily, Italy was investigated from May 2004 until June 2006. Samples were sampled monthly from a network of 50 rain gauges. During the same period 580 groundwater samples were collected from springs and wells to obtain insight into the isotopic composition of the water circulating in the main aquifers of the area. The mean weighted precipitation values were used to define the weighted local meteoric water line for five different sectors of Sicily. The use of Geographical Information System tools, coupled with isotopic vertical gradients, allowed designing an isotopic contour map of precipitation in Sicily. The defined meteoric compositions were highly consistent with most of the groundwater samples in each sector. However, in some areas fractionation processes occurring during and after rainfall slightly modify the isotopic composition of the groundwater. The obtained data set defines the present day isotopic composition of meteoric water in the central Mediterranean area and provides baseline values for future climatic and/or isotope-based hydrology studies.