1:25万毕节县幅、遵义市幅地质调查成果与进展

在毕节青场桐梓组顶部至石炭系中发现有大量的暴露构造现象;发现毕节地区中二叠世茅口期存在两条走向北北东、宽10~50km的“黑区带”;在威信县城第四系中发现大量象牙、牙齿及骨骼化石;在凤冈琊川、遵义茅坡及威信鱼井等新发现多个志留纪植物化石;对黔中隆起进行了研究。     

The role of hydrothermal fluids in sedimentation in saline alkaline lakes: Evidence from Nasikie Engida,Kenya Rift Valley

Saline alkaline lakes that precipitate sodium carbonate evaporites are most common in volcanic terrains in semi‐arid environments. Processes that lead to trona precipitation are poorly understood compared to those in sulphate‐dominated and chloride‐dominated lake brines. Nasikie Engida (Little Magadi) in the southern Kenya Rift shows the initial stages of soda evaporite formation. This small shallow (<2 m deep; 7 km long) lake is recharged by alkaline hot springs and seasonal runoff but unlike neighbouring Lake Magadi is perennial. This study aims to understand modern sedimentary and geochemical processes in Nasikie Engida and to assess the importance of geothermal fluids in evaporite formation. Perennial hot‐spring inflow waters along the northern shoreline evaporate and become saturated with respect to nahcolite and trona, which precipitate in the southern part of the lake, up to 6 km from the hot springs. Nahcolite (NaHCO₃) forms bladed crystals that nucleate on the lake floor. Trona (Na₂CO₃·NaHCO₃·2H₂O) precipitates from more concentrated brines as rafts and as bottom‐nucleated shrubs of acicular crystals that coalesce laterally to form bedded trona. Many processes modify the fluid composition as it evolves. Silica is removed as gels and by early diagenetic reactions and diatoms. Sulphate is depleted by bacterial reduction. Potassium and chloride, of moderate concentration, remain conservative in the brine. Clastic sedimentation is relatively minor because of the predominant hydrothermal inflow. Nahcolite precipitates when and where pCO₂ is high, notably near sublacustrine spring discharge. Results from Nasikie Engida show that hot spring discharge has maintained the lake for at least 2 kyr, and that the evaporite formation is strongly influenced by local discharge of carbon dioxide. Brine evolution and evaporite deposition at Nasikie Engida help to explain conditions under which ancient sodium carbonate evaporites formed, including those in other East African rift basins, the Eocene Green River Formation (western USA), and elsewhere.     

运用H、O同位素分析石阡地区地热水来源

通过对贵州省石阡地区地热水、冷泉及河流的地热地质条件、水化学成分及氢氧同位素分析,对该地区的地热水、冷泉及河流的水化学特征、来源及石阡地区的补给模式进行了研究.温泉水属于低中矿化度的弱碱性水;温泉群中阳离子以Ca2+、Mg2+为主,阴离子以SO42-和HCO3-为主,研究区水化学类型主要为HCO3-Ca和SO4.HCO...     

Genesis of Geothermal Fluid in Typical Geothermal Fields in Western Sichuan,China

The hydrogeochemical characteristics of geothermal fluids can reveal the genesis of geothermal systems and act as important references for developing and using geothermal resources.This study presents hydrogeochemical processes and thermal cycle mechanisms of typical geothermal fields in Western Sichuan.Based on the geological conditions in Western Sichuan,29 hot springs in three geothermal fields in the Batang and Litang areas were selected for hydrochemical and isotopic (δD andδ~(18)O) analyses.Furthermore,the temperature of the thermal reservoir was calculated and the upflow cooling process of the hot springs was analyzed.Most of the subterranean hot waters in Batang and Litang are of the HCO_3-Na hydrochemical type.The ion variation in Batang is primarily affected by water-rock interactions.There is a strong positive correlation between Na~+,B~-,and Cl~-in Litang,suggesting that they have the same material source.The Na~+and metaboric acid content is relatively high,which indicates that the groundwater runoff in both areas is relatively long-lasting,with reduced flow velocity;moreover,the metasilicic acid content is relatively high,which supports this conclusion.Both hydrogen and oxygen isotopes plot near the atmospheric precipitation line,indicating that groundwater recharge is functionally obtained from precipitation.The calculated thermal storage temperatures in Batang and Litang were 88–199°C and 96–154°C,respectively.The proportion of cold water mixing in Batang was 64%–67%,while that in Litang was 60%–68%.According to the calculated results,the initial thermal cycle depth of the Batang area (4540–4780 m) was greater than that of the Litang area (3150–3960 m).The enthalpy of the deep parental geothermal fluid in Batang was 1550 J/g with a Cl~-concentration of 37 mg/L,while that in Litang was 2100 J/g with a Cl~-concentration of 48 mg/L.     

箱形基础上浮病害整治技术

结合箱形基础不均匀上浮工程病害实例，综合分析了病害原因，提出了应用高压灌浆和抗浮锚杆工艺进行处治的方案。     

微动技术在堤坝渗漏探测中的应用

堤坝是重要的水利工程,其安全性至关重要。坝体渗漏是常见的安全隐患之一,对坝体渗漏位置、程度以及坝体结构变化的探测一直是重要的物探课题。微动勘探作为一种新兴的物探手段,应用范围正逐步拓展,通过某水库大坝渗漏检测实例,展示频率-波数法微动线性点阵剖面测量进行大坝渗漏检测的效果,该技术通过提取频散曲线及视S波速度成像,刻画地层速度结构并圈定异常,可实现对大坝渗漏快速精确的无损探测,具有一定的方法优势和广泛的应用前景。     

电感耦合等离子体质谱-X射线衍射法研究云南玉溪和美国内华达地区黏土型锂资源矿物学特征

中国云南玉溪和美国内华达均已发现大量黏土型锂资源,目前关于两地区样品矿物学特征的研究相对不足,而对黏土型锂资源进行充分的矿物学特征研究是锂提取工作开展的重要前提.本文采用X射线荧光光谱、电感耦合等离子体质谱、X射线粉晶衍射、扫描电镜等分析技术,从化学组成、矿物组成、微观形貌等角度对云南玉溪的两个黏土型锂资源样品(YM-...     

基于Origin的渗透系数衰减方程在地热水回灌中的应用

孔隙型热储层的回灌过程中,由于物理堵塞、生物化学堵塞、悬浮物堵塞和气体堵塞,热储层的渗透性下降,回灌能力变弱.为了定量查明渗透系数的衰减,以辽南地区某回灌试验为例,使用Origin软件计算出研究区渗透系数衰减方程,在此基础上计算了回灌井灌压-时间关系曲线和回扬周期.研究表明,利用Origin软件求取渗透系数衰减方程具有...     

冲-洪积平原1:5万区域地质调查技术方法探索

首都地区规划建设工作主要分布于平原松散地层之上,第四纪地质研究显得尤为重要。依托近几年来在北京地区开展的平原覆盖区1:5万区域地质调查和活动断裂专项调查项目成果,系统总结了平原区第四纪区域地质调查与评价的主要工作手段和技术方法,及其在解决第四纪基础地质问题及生态环境中所起的作用。通过平原区区域地质调查工作,可查明第四纪精细地质结构、含水层分布特征,精确厘定活动断裂位置及其活动时限,探讨自然环境演化序列与人类活动关系等,为城市规划、重大工程建设和应急水源地水资源合理开采提供基础地学数据。研究成果对首都城市减灾防灾、生态环境演变研究具有重要地学支撑作用。