江西花岗岩地区氡水异常的找矿意义

氡水异常(水中铀和镭含量不够异常值的单氡型水异常)在花岗岩地区非常发育,因而研究氡水异常与铀矿化的关系具有重要意义。其一是可以使我们正确确定水化找矿标志,提高水化找矿效果,其二是为氡水异常的解释和揭露评价提供理论依据。本文根据江西地区5个岩体13个矿床的水化找矿资料,对氡水异常的形成条件及其与铀矿化的关系进行了探讨,提出几点认识和看法。     

“赣-杭铀成矿带”中的放射性水化异常及对铀成矿的指示

在收集和分析大量水化异常点元素含量数据基础上,总结了水化异常区域分布规律,将放射性水化异常划分为铀水异常、氟水异常和铀.氧水异常三种类型,认为铀.氡型水异常与铀矿化关系最密切,其见矿率最高,铀水异常次之,而氡水异常是三类水异常中见矿率最低的.同时探讨了甄别真假放射性水异常的方法,提出水中铀同位素比值与水中铀总量关系分布曲线呈负相关收敛趋势,是寻找内生热液型铀矿化的标志;水中铀同位素比值与水中铀总量关系分布曲线正相关呈离散趋势,是寻找外生沉积铀矿化的标志.     

模拟水氡异常判识

本文阐述了模拟水氡测值的影响因素,并以乌鸦咀泉为例阐述了模拟水氡异常的判识方法,指出要对模拟水氡异常进行判识,必须充分了解水点的基本情况及所有影响因素,并充分了解这些影响因素对水氡的影响规律,在此基础上对干扰因素加以排除,同时用同一水点其它测项的同步变化特征来佐证该异常不是观测过程中人为及仪器因素造成,最后进行区域背景场对比分析,用同一区域其它水点测值的同步变化情况加以佐证,以判断是否是区域应力场所致,从而为分析预报提供可靠的判定依据。本文为模拟水氡的异常判识提供了实例。     

砂岩型铀矿床上氡及其子体异常分析

本文分析了砂岩型铀矿床上氡及其子体异常特征及其形成的机理，分析了砂岩型铀矿床的地质特点、U-Ra平衡、粒子反冲、团簇效应和自然电场等，对砂岩型铀矿床上氡及其子体异常的分布规律进行了探讨。     

砂岩铀矿床上氡及其子体异常成因

分析了砂岩型铀矿床上氡及其子体异常特征及其形成的机理,介绍了砂岩型铀矿床上氡及其子体经α衰变后产生的α粒子的反冲现象、团簇理论和自然电场,分析了砂岩铀矿床的地质特点、U-Ra平衡、磁化率、自然电位的变化等,对砂岩铀矿勘查的氡及其子体异常解释有一定的指导意义。     

~(222)Rn的吸附性及其对水异常评价的意义

本文依据活性炭、粘土、砂对水中氡进行吸附的试验资料及204地区的野外实际资料,探讨了氡的吸附性。含氡地下水在径流过程中除衰变,逸出会使其氡浓度降低外,岩土对其吸附亦是重要因素。因此,在进行放射性水异常评价时,应充分注意这一点。     

氡及其子体测量在东胜砂岩铀矿勘查中的应用

通过对砂岩型铀矿地区氡及其子体的测量及对异常形成机理的分析, 进一步研究数据处理和解释方法。东胜地区实测资料表明了氡及其子体低值异常对应成矿相对有利的地段, 说明了解释方法的有效性, 为充分发挥攻深能力强的氡及其子体方法在铀矿找矿中的作用奠定基础。     

活性炭吸附测氡法在北秦岭柳树湾铀矿床勘查中的应用

在北秦岭东段柳树湾地区开展的活性炭吸附法测氡实验结果表明,该地区氡浓度异常峰值高、连续性好,总体呈北西走向,主要沿岩体与地层接触带中的伟晶岩走向分布,其分布范围及规模明显受伟晶岩控制。通过对发现的氡浓度异常点进行钻探验证表明,氡浓度异常均为矿致异常,与深部含矿伟晶岩密切相关,能够很好的反映出隐伏伟晶岩的铀矿化信息。该方法为确定铀矿找矿有利地段提供了重要依据,对本区花岗伟晶岩型铀矿深部找矿具有重要的指导意义。     

砂岩型铀矿氡及其子体测量异常特征

氡及其子体测量用于寻找砂岩型铀矿床上能够形成清晰的异常,但氡及其子体测量方法较多且各具有不同的特点。总结几种常用的氡及其子体测量方法在砂岩型铀矿上的异常特征,并进行比较分析,结果表明铀矿体所在部位大都具有明显的负异常特征,而矿体的头、尾部多呈正异常,其中累积测量比瞬时测量的异常特征更加明显,对应钻孔的位置更好。     

氡、氦等气体地球化学在地震科学研究中的进展

系统回顾了氡、氦的气体地球化学特征及其在地震科学研究中的应用情况。在分析氡、氦等地下气体在地壳中浓度变化的影响因素基础上,总结出氡、氦等地下气体浓度变化具年变（或日变）规律,且受多种因素诸如其自身的地球化学行为、气候条件、地质构造及区域应力场等的综合影响。归纳了近30年来在氡、氦的理论和实验研究以及氡异常的形成机理研究方面所取得的进展。氡、氦等地下气体在地震监测预报及基础研究方面日益发挥出越来越重要的作用,但对其自身的认识还远远不够,提出了今后应在氡、氦等地下气体的异常迁移、实验研究、资料处理过程中对干扰因素的排除以及开展深部气体运移与地震活动的关系等方面开展研究的建议。     

福建水氡对闽台地震的映震分析

利用福建水氡台网 1 990年以来的水氡资料 ,针对 6次福建及其东南沿海大于 4 5级地震 ,7次台湾及其近海大于 6 8级地震进行分析研究 ,认为地震前异常存在加速性、同步性 ,形态的多样性 ,空间分布的不确定性。运用“九五”攻关软件 ,给出上述两区域地震异常特征的共性和个性 ,并对映震效能进行R值评分     

使用水力屏障控制单一倾斜储层中CO2羽的迁移

摘要:在单一倾斜含水层中封存CO₂时,在浮力作用下,CO₂会向地层上升一侧快速运移,不利于封存安全.可在倾斜地层的上升一侧,距离CO₂注入井一定位置设置注水井,创造水力屏障,以阻止CO₂向上移动.建立了数值模型来探讨这一方法的有效性,分析注水位置、距离、速度等因素的影响.结果表明注水形成的水力屏障能有效阻挡CO₂羽的向上迁移,且能促进CO₂溶解,抽水能显著降低地层压力.为了确保能完全阻挡CO₂运移,需要注水长度大于CO₂羽的厚度,甚至是在全部储层注水.注水速度是影响水力屏障效果的关键因素.注水距离越近阻挡效果越好.可以在CO₂羽即将到达之前注水,以减少注水量和能源消耗.      

Radon in groundwater in Tumkur district of Karnataka with special reference to sampling sensitivity

Radon is a naturally occurring colourless and odourless radioactive gas that is soluble in water and is the main source of radioactivity of groundwater. Use of radon contaminated groundwater increased the radon levels in the air, especially in poorly ventilated houses, which is hazardous to health. Ingestion of such water for quite long period may lead to stomach cancer. The drinking water standards proposed by the Bureau of Indian Standards (BIS) exclude the permissible concentration of radon in drinking water. The US Environmental Protection Agency (USEPA) in 1991 proposed a Maximum Concentration Level (MCL) of 11.1 Bq/l for public water supply. The water samples from the bore wells in Tumkur district of Karnataka show radon concentrations in the range of 5 to 250 Bq/l. Ninety percentages of the samples show radon levels above the permissible limit as per USEPA. The spatial variation and geological control over radon concentration in groundwater in the area and sampling sensitivity are discussed here. The study was conducted during March 2012.     

Study of the radon concentrations in drinking water from three main cities of Shaanxi Province,China

This paper presents the results of radon concentration measurements in the drinking water from the municipal water supply system and private wells of Xian, Xianyang and Baoji city of Shaanxi province of China. The measurements were carried out on 38 samples. Radon levels in drinking water in Xian, Xianyang and Baoji were found to be 5.78, 13.04 and 15.01 k Bq m^–3, respectively. The AM radon concentration of private well water from Xianyang and Baoji is 28.84 k Bq m^–3 and 38.85 k Bq m^–3, respectively, which is 2.56 times and 3.14 times as high as that of tap water radon, respectively. The radiation risk of radon in water would be due to degassing and not due to drinking water. The domestic use of showers, humidifiers, and cooking, washing up, laundering, etc. may lead to an additional increase of the radon concentration in the indoor air. The observed radon concentration in drinking water from three main cities of Shaanxi Province can contribute to a 4.86 to 32.63% increase in indoor radon concentration and can cause 0.068±0.016 mSv y^–1 to 0.177±0.045 mSv y^–1 extra annual effective dose to males, 0.060±0.014 mSv y^–1 to 0.155±0.039 mSv y^–1 to females. The mean annual effective dose equivalents to males and females of Xianyang and Baoji from well water account for 25.94 to 39.75% of environmental radon and radon daughters annual effective dose equivalents. The radon concentrations in the well water from Xianyang and Baoji will bring a definite additional risk to the population.     

浅覆盖区陆相盆地高频层序划分与岩石化学的对比——以大兴安岭北段上黑龙江盆地绣峰组为例

利用岩石化学中各种氧化物及相关比值在陆相盆地沉积作用中的不同表现性质, 讨论了上黑龙江盆地绣峰组Ⅳ级层序形成的气候、水体、沉积体系及基准面变化特征.绣峰组Ⅳ级层序自下部向中部Fe₂O₃、Fe3+/Fe2+、K₂O、Na₂O等值逐渐减小; MnO、FeO、MgO、LOS等含量逐渐增高; 层序中部向上部Fe₂O₃、K₂O、Na₂O等值逐渐增大, MnO、FeO等含量逐渐减少, 显示了绣峰组Ⅳ级层序在气候旋回控制下由水体加深、气候潮湿向水体变浅、气候干旱演变的中期基准面对称旋回特征.这一研究成果为陆相盆地高频层序划分提供了新思路.      

鄂尔多斯盆地山西组地下咸水CO2溶解能力

实施CO₂的地质储存是目前公认的减缓全球变暖的有效途径之一.潜在的储存场所包括衰竭的油气藏、深部不可开采煤层及深部咸水层.其中, 深部咸水层储存潜力最大.在发挥作用的诸多机理中, 溶解埋存具有埋存量大、作用时间较长以及安全性高的特点.在评价深部咸水含水层CO₂溶解储存潜力时, 溶解度是一个关键参数.提出了测定咸水含水层地层水CO₂溶解度的方法, 并将其实际应用于鄂尔多斯盆地山西组地层水.鄂尔多斯盆地是我国重要的能源基地, CO₂排放量大, 排放浓度高.采集了野外实地水样, 进行了化学成分分析, 并人工合成该水样; 测定了40~80 ℃、8~12 MPa条件下CO₂在该水样中的溶解度, 其结果可为评价鄂尔多斯盆地深部咸水含水层埋存能力提供依据.      

我国斜发沸石、丝光沸石的阳离子类型和硅铝比

本文根据大量样品数据,提出划分沸石离子类型的主、次阳离子原则和单离子类型原则。进而对我国几十个矿点的大量随机样品进行分类,结果形成Ca、K、Na三个系列,K-Ca.Ca-K等12种离子类型。同时弄清了我国沸石的特点是以各种Ca型为主,以各种K型居其次。     

Response changes of some wells in the mainland subsurface fluid monitoring network of China, due to the September 21, 1999, Ms7.6 Chi-Chi Earthquake

About 60 hydrologic changes in response to the Chi-Chi earthquake with Ms7.6 on September 21, 1999, occurred in 52 wells, including groundwater level, temperature, discharge rate, well pressure and radon, etc., in the subsurface fluid monitoring network. These response changes were mainly co-seismic, but some pre- and post-earthquake changes occurred mainly within 5 days before and after the Chi-Chi earthquake. The response changes of different wells clustering in different tectonic areas showed different features. These changes are distributed in five areas named as A, B, C, D and E. The response changes in A area with short hypo-central distance (less than 550 km) were mainly pre-earthquake changes occurring more than 5 days before the event. Those in area B (in Huanan tectonic block) and C (in Huabei tectonic block) were mainly co-seismic changes. The hypo-central distance is about 1100–1280 and 800–1160 km, respectively. These changes were high-frequency water-level oscillations induced by seismic waves and accompanied by prominent and permanent water-level jumps and drops. There are also some post-seismic changes including discharge rate and water radon and well pressure changes in area C. Those in area D in the Yanshan tectonic block were mainly co-seismic and post-seismic changes including water level, water temperature, and water radon concentration, etc., showing prominent and permanent water-level jumps and drops and rising concentrations of water radon. The hypo-central distance is about 1750–2060 km. Those in Area E were mainly co-seismic changes showing prominent and permanent water-level jump. The hypo-central distance is about 1810–2120 km. Three moderate earthquakes occurred in area D and one strong earthquake occurred in area E 4 months after the Chi-Chi earthquake. The different features of the response changes might be caused by the changes of local hydrologic conditions (like permeability) induced by seismic waves. On the other hand, these response changes might indicate the near-critical conditions in the area where the response changes clustered. Such changes might be understood by the crustal buckling hypothesis. It is thought that the response changes might be a kind of precursor that implies elevated earthquake risk in the region.     

岩溶洞穴系统SO42-、NO3-来源及其对水岩作用的影响

为揭示洞穴系统中SO₄2-和NO₃-离子来源及其对洞穴碳酸盐溶解的影响,通过对麻黄洞6个水点自2018年8月至2019年7月进行为期一个完整水文年的系统监测,对于监测结果进行综合分析.结果表明:（1）麻黄洞洞穴水水化学类型为HCO₃-Ca·Mg以及HCO₃·SO₄-Ca·Mg型;（2）通过实地调查与元素比值法综合分析可知,麻黄洞NO₃-与SO₄2-各水点来源存在一定差异,其中麻黄洞NO₃-主要源于农业活动和大气N沉降,而SO₄2-主要以农业活动、石膏溶解为主要来源,SO₄2-和NO₃-均参与了岩溶作用,加速了基岩的溶蚀,这一过程主要受离子浓度、径流大小以及补给模式影响;（3）基于水化学计量法和稳定同位素技术估算可知,SO₄2-和NO₃-洞穴水DIC的贡献为0.05~0.61,释放DIC的同时改变了水中离子浓度,对于岩溶作用形成扰动,总体呈现出旱季>雨季、滴水>裂隙水的特征.同样,由于岩溶区的复杂和不可知,在对其进行系统研究时应当注重多种方法的结合与比较,提高研究精度与可信度.      

The Use of Multiple Reference Samples for the Monitoring of Ion Microprobe Performance During Zircon 207Pb/206Pb Age Determinations

Data from a series of extended analytical sessions using a range of different zircon reference samples have been used to investigate the periodic derivation of abnormal ²⁰⁷Pb/²⁰⁶Pb ages during microbeam analysis%For the Canberra SHRIMP II, this phenomenon probably results from the presence of a signal at mass 204 that is alien to the Pb spectrum; isotopic fractionation is unlikely to be a significant contributor. In contrast, abnormal ²⁰⁷Pb/²⁰⁶Pb ages obtained from SHRIMP I at the same research centre require a different, but as yet unknown explanation. Assessment of the reasons for atypical ^207Pb/²⁰⁶Pb measurements and the means of correcting for them should therefore be independently assessed for individual analytical instruments. The use of reference samples with very different ages is an effective way of doing this, because older reference samples are more useful for documenting isotopic fractionation, whereas younger ones are more sensitive indicators of isobaric interference.