一种大地电磁成像技术

文中将层析成像技术中广泛采用的广义脉冲谱技术应用了解大地电磁 维反演成像问题,实现了电阻率剖面成像.由于在做有限元二维止演的同时,就完成了Frechet导函数的计算,从而提高了反演的速度。文中给出了模型、实例的计算,均取得了较好的效果.     

Potentially harmful metals,and health risk evaluation in groundwater of Mardan,Pakistan: Application of geostatistical approach and geographic information system

This study investigates the values of pH, total dissolved solids (TDS), elevation, oxidative reduction potential (ORP), temperature, and depth, while the concentrations of Br, and potentially harmful metals (PHMs) such as Cr, Ni, Cd, Mn, Cu, Pb, Co, Zn, and Fe in the groundwater samples. Moreover, geographic information system (GIS), XLSTAT, and IBM SPSS Statistics 20 software were used for spatial distribution modeling, principal component analysis (PCA), cluster analysis (CA), and Quantile-Quantile (Q-Q) plotting to determine groundwater pollution sources, similarity index, and normal distribution reference line for the selected parameters. The mean values of pH, TDS, elevation, ORP, temperature, depth, and Br were 7.2, 322 mg/L, 364 m, 188 mV, 29.6 °C, 70 m, 0.20 mg/L, and PHMs like Cr, Ni, Cd, Mn, Cu, Pb, Co, Zn, and Fe were 0.38, 0.26, 0.08, 0.27, 0.36, 0.22, 0.04, 0.43 and 0.86 mg/L, respectively. PHMs including Cr (89%), Cd (43%), Mn (23%), Pb (79%), Co (20%), and Fe (91%) exceeded the guideline values set by the world health organization (WHO). The significant R² values of PCA for selected parameters were also determined (0.62, 0.67, 0.78, 0.73, 0.60, 0.87, ?0.50, 0.69, 0.70, 0.74, ?0.50, 0.70, 0.67, 0.79, 0.59, and ?0.55, respectively). PCA revealed three geochemical processes such as geogenic, anthropogenic, and reducing conditions. The mineral phases of Cd(OH)_2, Fe(OH)_3, FeOOH, Mn₃O_4, Fe₂O_3, MnOOH, Pb(OH)_2, Mn(OH)_2, MnO_2, and Zn(OH)₂ (?3.7, 3.75, 9.7, ?5.8, 8.9, ?3.6, 2.2, ?4.6, ?7.7, ?0.9, and 0.003, respectively) showed super-saturation and under-saturation conditions. Health risk assessment (HRA) values for PHMs were also calculated and the values of hazard quotient (HQ), and hazard indices (HI) for the entire study area were increased in the following order: Cd>Ni>Cu>Pb>Mn>Zn>Cr. Relatively higher HQ and HI values of Ni, Cd, Pb, and Cu were greater than one showing unsuitability of groundwater for domestic, agriculture, and drinking purposes. The long-term ingestion of groundwater could also cause severe health concerns such as kidney, brain dysfunction, liver, stomach problems, and even cancer.     

机载LiDAR技术在公路建设中的应用——以喀喇昆仑公路为例

以喀喇昆仑公路为研究对象,规划机载Li DAR地形测绘流程,并对该过程中的数据采集、数据处理进行了分析。积累和掌握机载激光雷达在公路建设中的经验,证明该技术可以提高我国公路建设的质量和效率,对拓展机载激光雷达技术的应用具有重要意义。     

鄂尔多斯盆地盐池-定边地区长7段烃源岩芳烃地球化学特征

基于鄂尔多斯盆地盐池-定边地区13口井16块长7烃源岩样品的GC-MS分析资料,研究了源岩的芳烃地球化学特征,进行了生源和沉积环境的分析,并探讨了芳烃系列成熟度评价参数在该地区的有效性。研究结果显示:研究区源岩主要以二环和三环芳烃类化合物为主,而四环和五环芳烃类化合物较低,芴含量较高,普遍含有1,2,5-TMN和1,2,5,6-TeMN且部分样品含量偏高,并检测出一定含量的惹烯、苝、和芘等陆源高等植物生物标志化合物,表明研究区源岩形成于滨浅湖弱氧化-弱还原的环境中,高等植物的输入对该地区源岩的形成占有一定贡献。芳烃中烷基萘、烷基菲和烷基二苯并噻吩等成熟度参数表明源岩样品现今正处于成熟阶段。虽然利用不同系列芳烃类化合物求取的等效镜质体反射率存在一定差异,但能定性地反映出源岩的热演化程度。     

连云港徐圩地面沉降BOTDR监测与评价

连云港市位于苏北沿海地区,地面沉降灾害面积较大,多地沉降速率超过20 mm/a,徐圩的沉降现状尤为严重。为了能够对徐圩地区的地面沉降进行精细化观测,文章采用BOTDR分布式光纤感测技术,对徐圩镇127 m深的钻孔地层进行了两年多的全断面精细化监测。结果表明:徐圩镇共有四个承压含水层组,I-1隔水层和I-2隔水层土体沉降量分别占总沉降量的70.29 %、24.59 %,抽水层的土体最大沉降量仅占比1.38 %。I-1隔水层和I-2隔水层的地层岩性包括淤泥质黏土（L2）、亚黏土（L3）、亚砂土夹粉砂（L4）,总厚度为44 m,由于抽水过程中隔水层向含水层失水,导致该隔水层土体固结压缩。同时,工程建设附加荷载对地面沉降的影响也不可忽视。徐圩地区现阶段的沉降仍在继续发生,但沉降速率有减小的趋势。BOTDR技术可有效获取地面沉降钻孔全断面的土层变形分布信息,为地面沉降评价提供了一种精细化的分布式监测手段。     

Lacustrine fan delta deposition alongside intrabasinal structural highs in rift basins: an example from the Early Cretaceous Jiuquan Basin,Northwestern China

International Journal of Earth Sciences - Development of fan deltas alongside intrabasinal structural highs has been overlooked compared to those forming on basin margins. However, these fan deltas...     

病险水库理论分析研究进展

中国病险水库数量庞大,目前国内正有计划分步开展水库除险加固工作,除险加固的理论方法研究已成为当前研究的重要课题。在总结相关研究成果的基础上,将病险水库除险加固的研究分为理论分析方法和加固技术措施两方面,进而从风险分析与安全评价、结构分析方法以及除险加固效果量化研究三方面阐述了当前研究进展与不足。同时指出,考虑中国病险坝特点和机理的风险分析与安全评价、结构正反分析方法及除险加固效果的量化评价研究是未来病险水库除险加固理论分析研究的重点。     

豫西济源盆地侏罗系泥质岩地球化学特征及其 环境和物源示踪

本文通过对济源盆地侏罗系泥质岩样品的微量元素及稀土元素测试,探讨了其形成的环境和物源。稀土元素球粒陨石标准化后表现为轻稀土元素富集的右倾式,δEu均值0.64,中度负异常,δCe均值0.90,轻微亏损,LREE/HREE、(La/Yb)N均值分别为9.1和9.5,轻重稀土分异明显。利用地球化学方法分析了该盆地侏罗纪沉积环境及物源特征,结果表明:济源盆地侏罗纪总体处于弱氧化—还原环境,且还原性自下而上依次减弱,水体逐渐变浅;早侏罗世鞍腰组和中侏罗世早期杨树庄组沉积时期,济源盆地处于鄂尔多斯大型盆地开放体系中,气候逐渐干旱并未影响水体盐度,总体为淡水沉积;中侏罗世晚期马凹组沉积时期,太行山复背斜隆升使济源盆地完全封闭,气候干旱造成水体盐度增大,总体为半咸水沉积;济源盆地侏罗系沉积物源自下而上有长英质物质逐步减少、基性火成物质逐步增加的趋势,说明济源盆地在侏罗纪受到太行山复背斜隆升和剥蚀的控制,其早期大量物源来自复背斜上被剥蚀的复旋回长英质盖层,到晚期,随着复背斜的隆升和剥蚀的加强,其核部古元古—太古界基性物质成为盆地重要的沉积物源之一。与此同时,秦岭造山带也向济源盆地侏罗系贡献了部分物源。因此,济源盆地的侏罗系揭示了太行山复背斜逐步隆升-剥蚀的过程,成为我们理解华北克拉通破坏的一个重要窗口。     

近30年来长江口水下三角洲地形演变与受控因素分析

利用长江口1982-2010年间4个年份的高精度实测地形数据、大通站输沙量数据以及河口工程建设信息等,分3个阶段研究了长江口整体冲淤规律、不同分区冲淤变化时空差异、重点断面垂向冲淤特征、水下三角洲重要区域 (崇明东滩、横沙浅滩、九段沙以及南汇东滩) 的演变趋势与受控因素。结果表明：(1) 近30年长江口整体上表现为略微冲刷,冲刷面积占51.83%,在3个阶段中呈现出“冲刷—淤积—再冲刷”的冲淤演化态势,且冲淤变化时空差异显著,仅长江北港区为持续冲刷。(2) 崇明东滩和横沙浅滩东侧和北侧、九段沙北侧以及南汇东滩的5 m以浅区域以垂向淤积为主,而崇明东滩和横沙浅滩南侧、九段沙东侧和南侧的5 m以浅区域则以垂向冲刷为主。(3) 长江口重要区域2 m和5 m等深线包络面积整体上是不断增加的,1982-2010年时段内年均增加量分别为10.42 km²/a和7.99 km²/a,但各分区则表现不一致;10 m等深线包络面积在整体上及各个分区内均表现为明显减小;15 m等深线包络面积变幅较小,基本保持稳定状态;(4) 受河口工程建设影响,仅崇明东滩水下三角洲等深线包络面积减小的趋势与大通站输沙量减少趋势相同。主要结论：从长江口水下三角洲等深线包络面积和分布形态的变化看,基于目前上游输沙量持续减少的宏观自然背景下,大规模的河口工程建设对近年来长江口水下三角洲演变的控制作用日益明显。     

Grassland coverage inter-annual variation and its coupling relation with hydrothermal factors in China during 1982–2010

GIMMS (Global Inventory Modeling and Mapping Studies) NDVI (Normalised Difference Vegetation Index) from 1982 to 2006 and MODIS (Moderate Resolution Imaging Spectroradiometer) NDVI from 2001 to 2010 were blended to extract the grass coverage and analyze its spatial pattern. The response of grass coverage to climatic variations at annual and monthly time scales was analyzed. Grass coverage distribution had increased from northwest to southeast across China. During 1982–2010, the mean nationwide grass coverage was 34% but exhibited apparent spatial heterogeneity, being the highest (61.4%) in slope grasslands and the lowest (17.1%) in desert grasslands. There was a slight increase of the grass coverage with a rate of 0.17% per year. Increase in slope grasslands coverage was as high as 0.27% per year, while in the plain grasslands and meadows the grass coverage increase was the lowest (being 0.11% per year and 0.1% per year, respectively). Across China, the grass coverage with extremely significant increase (P<0.01) and significant increase (P<0.05) accounted for 46.03% and 11% of the total grassland area, respectively, while those with extremely significant and significant decrease accounted for only 4.1% and 3.24%, respectively. At the annual time scale, there are no significant correlations between grass coverage and annual mean temperature and precipitation. However, the grass coverage was somewhat affected by temperature in alpine and sub-alpine grassland, alpine and sub-alpine meadow, slope grassland and meadow, while grass coverage in desert grassland and plain grassland was more affected by precipitation. At the monthly time-scale, there are significant correlations between grass coverage with both temperature and precipitation, indicating that the grass coverage is more affected by seasonal fluctuations of hydrothermal conditions. Additionally, there is one-month time lag-effect between grass coverage and climate factors for each grassland types.