A preliminary study on the spatial distribution characteristics and causes of strontium-rich mineral water in the Dushan complex

The mountain rocks in the Dushan Complex are Sr-rich granite with a much higher Sr level than those in other crustal lithospheres in eastern China. That presents a high potential for developing Sr-rich mineral water. In this study, 6 groups of rock samples, together with 30 groups of water samples, were collected. Combining with the existing data, the Sr contents in three different types of underground water were obtained, which are the Quaternary pore water, the meshed bedrock fissure water in weathered zones and the tectonic bedrock fissure water. On the basis of preliminary understanding for the distribution characteristics of Sr-rich mineral water in the Dushan Mountain region, the causes for the Sr-rich mineral water were investigated. Our results showed that the Sr content of the rocks in the studied area ranges from 988 to 1 950 μg/g. In the horizontal direction, those in both the pore water and the meshed bedrock fissure water in weathered zones show high values in the west but low ones in the east, and high ones in the south but low ones in the north. Furthermore, both types of water meet the standard for Sr-rich mineral water in the western areas. In the vertical direction, the Sr content shows the lowest value in pore water(the average value is 0.707 mg/L), middle value in the meshed bedrock fissure water in weathered zones(the average value is 1.415 mg/L) and the highest value in the tectonic bedrock fissure water(the average value is 8.331 mg/L). It was thought that the widely-developed Sr-rich granite in this region provides physical sources for the formation of Sr-rich mineral water. The continuous dissolution of Sr during underground water runoff is the internal mechanism. In addition, the hydraulic interrelations may exist between the three vertical aquifers, leading a continuous accumulation of the Sr level during infiltration.     

北淮阳东段卢镇关群和佛子岭群地层含矿性地球化学评价

卢镇关群和佛子岭群广泛分布于北淮阳成矿带内,但是对其含矿性研究一直较为薄弱。文章通过对卢镇关群和佛子岭群成矿元素的地球化学特征研究,评价地层含矿性。成矿元素富集系数(K)分析表明卢镇关群和佛子岭群各组中Mo元素均富集,W、Pb、Ag、Cu元素也存在不同程度的富集,存在潜在成矿可能;成矿元素后期叠加强度(D)分析表明本区的Mo、Ag、Cu等元素存在不同程度的后期叠加作用;成矿元素变异系数(CV)分析表明本区成矿元素具有一定的成矿潜力。对卢镇关群和佛子岭群成矿能力评序得出最优势矿种为Mo元素,并且卢镇关群和佛子岭群是北淮阳钼矿的理想矿源层,为区内钼矿提供了成矿物质。成矿元素与主微量元素的相关性分析表明Cu、W、Ag、Pb、Zn等元素受碎屑岩特征和氧化还原环境控制。     

长春地区粉质黏土导热系数与其物性参数相关性研究

为研究导热系数与影响因素之间的相关关系,建立导热系数的推算公式,以长春地区粉质黏土为研究对象,对原状土样的导热系数与其物理参数之间的相关性进行回归分析。制作9个重塑土样,测其相关的参数值,以验证回归方程的适用性。结果表明,回归分析建立导热系数与2个物理参数之间的关系式不成立;考虑天然密度、含水率和孔隙度为自变量,其分别对应的相关性系数T检验显著值(Sig)都0. 05,复决定系数为0. 886,建立的回归方程成立,自变量能准确解释因变量的变化,且含水率与导热系数呈负相关,天然密度和孔隙度呈正相关。重塑土样相关参数代入回归方程得到的导热系数值与实验实测值之间相对误差低于4%,验证了该回归方程的普遍性和适用性。     

土壤入渗对阜新市北部浅层地下水总硬度影响的淋滤实验

本次室内土柱淋滤实验通过改变Na~+、H~+、NH_4~+浓度来模拟现实生活中不同浓度的生活污水、酸雨及农业施肥灌溉对浅层地下水总硬度的影响过程。实验结果表明淋滤液浓度越高,所对应的淋出液的总硬度峰值就越高。相同浓度的Na~+、H~+、NH_4~+进行土柱淋滤实验时,NH_4~+所对应的淋出液总硬度的峰值最大,H~+次之,Na~+最小且NH_4~+所对应的整个实验用时最短,在相同浓度单一离子作用下NH_4~+对浅层地下水硬度的影响更加明显。     

中国历史极端干旱研究进展

中国现有抗旱相关法规、规划、标准和制度等均是按常态干旱考虑的,几乎没有考虑大范围、长历时极端干旱的问题。一旦发生类似崇祯大旱和光绪大旱等极端干旱,将对中国经济社会产生深刻影响。从历史旱涝序列重建、极端干旱事件复原和重演3个方面论述了相关研究进展,发现重建方面缺乏重建方法对比研究、重建序列时空分辨率较低等,复原方面缺乏干旱灾害双重属性的考虑等,重演方面缺乏对抗旱减灾能力以及全球气候变化的考虑等。对未来研究重点和实践需求进行了展望,指出需在不同重建方法交叉检验、高时空分辨率旱涝序列重建、基于自然灾害双重属性的历史极端干旱事件复原、历史极端干旱事件定量化重演和干旱巨灾风险应对战略等方面取得突破性进展。     

沟岸侧蚀对泥石流不稳定动力过程的影响

泥石流作为非牛顿体,屈服应力大,运动过程通常不稳定。前人建立了许多模型来研究沟床揭底和堰塞体溃决对泥石流不稳定动力过程的影响,沟岸侧蚀对泥石流不稳定动力过程的影响研究较少。通过侧蚀为主的模型和完全底蚀的模型两种水槽实验的对比,针对泥石流的动力过程展开研究。实验发现两种工况条件下泥石流正应力和孔隙水压力随着龙头高度沿程波动性的增长而相应地波动性增大,但侧蚀作用使得这种波动特征更加明显。通过力学分析,证明侧蚀作用导致泥石流龙头的阻力更大,但是龙身颗粒和龙头颗粒的速度差更大,使得龙头附加坡降更大,因此,侧蚀作用使得泥石流龙头的平均速度更快。泥石流龙头浓度和容重的不断增大,使得阻力不断增大,阻力和动力的动态平衡关系是泥石流不稳定运动的原因之一。     

综合物探方法在广西妙皇隐伏多金属矿勘查中的应用

妙皇多金属矿区位于来宾凹陷东缘与大瑶山隆起西侧交接部位,广西大瑶山及其西侧铅锌成矿带中部成矿条件优越,历年来开展过多种研究和找矿方法,但找矿效果不佳。通过研究妙皇铜铅锌银矿区的地质条件和成矿背景,运用综合物探方法,对区内部分地质问题及矿产特征进行了推断和预测。2012年,依据地质物探综合成果布置了ZK22701号验证孔,取得了突破性的进展。同时,依据物探成果推测了矿区成矿机理和成矿模式,在找矿方向和找矿潜力方面进行了分析探讨,对中深部找矿具有很好的指导意义。     

香溪河流域岩溶洞穴发育与分布特征

结合1∶5万水文地质调查,对香溪河岩溶流域溶洞特征进行了探究,统计其溶洞的规模、形态、发育地层、发育方向及分布高程,结果表明:该区洞穴规模中等,受岩性的控制,溶洞的发育表现出对碳酸盐岩岩组类型的选择性,其中寒武-奥陶系地层溶洞发育程度最高;溶洞的发育方向多为北北东和北北西向,与区域构造线一致,同时受本区构造运动间歇性抬升的影响,溶洞集中发育于4个高程区;从溶洞发育的构造部位来看,溶洞主要分布在宽缓向斜的东南翼及向斜核部,平面分布表现出分带性;该区溶洞多发育至早期就停止进一步发育,其规模、类型、分布特征等与鄂西南地区溶洞均存在差异。      

基于均一化资料的广州近百年气温变化特征研究

利用RHtest软件结合台站元数据对广州1908—2019年平均气温进行非均一性检验和订正,结果显示在1912、1928、1942、1988、1995、2004和2010年有7个显著的非均一间断点,订正后升温速率为1.39℃/(100 a),较订正前显著增加,具有准50 a和准3 a的显著周期。运用DB16正交小波分析其多时间尺度变化特征,结果显示方差贡献最大的是趋势分量,其次是准3 a和准6 a周期分量。趋势分量从20世纪40年代开始呈现持续的升温趋势;20世纪80年代中期至20世纪末的快速增暖是准50 a和准20 a周期分量的上升期叠加于趋势分量的结果;1998—2014年增暖停滞特征是准50 a、准20 a和准10 a这3个年代际周期分量的降温位相叠加在趋势分量上引起的。     

Spatiotemporal change patterns of urban lakes in China’s major cities between 1990 and 2015

China has experienced unprecedented urbanization in the past decades, resulting in dramatic changes in the physical, limnological, and hydrological characteristics of lakes in urban landscapes. However, the spatiotemporal dynamics in distribution and abundance of urban lakes in China remain poorly understood. Here, we characterized the spatiotemporal change patterns of urban lakes in China’s major cities between 1990 and 2015 using remote-sensing data and landscape metrics. The results showed that the urban lake landscape patterns have experienced drastic changes over the past 25 years. The total surface area of the urban lakes has decreased by 17,620.02?ha, a decrease of 24.22%, with a significant increase in the landscape fragmentation and a reduction in shape complexity. We defined three lake-shrinkage types and found that vanishment was the most common lake-shrinkage pattern, followed by edge-shrinkage and tunneling in terms of lake area. Moreover, we also found that urban sprawl was the dominant driver of the lake shrinkage, accounting for 67.89% of the total area loss, and the transition from lakes to cropland was also an important factor (19.86%). This study has potential for providing critical baseline information for government decision-making in lake resources management and urban landscape design.