首页> 外文OA文献 >Mapping localised freshwater anomalies in the brackish paleo-lake sediments of the Machile–Zambezi Basin with transient electromagnetic sounding, geoelectrical imaging and induced polarisation
【2h】

Mapping localised freshwater anomalies in the brackish paleo-lake sediments of the Machile–Zambezi Basin with transient electromagnetic sounding, geoelectrical imaging and induced polarisation

机译:利用瞬态电磁探测,地电成像和激发极化,绘制machile-Zambezi盆地咸水古湖沉积物中的局部淡水异常

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务,本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文,但由于OA文献来源多样且变更频繁,仍可能出现获取不到、文献不完整或与标题不符等情况,如果获取不到我们将提供退款服务。请知悉。

摘要

A recent airborne TEM survey in the Machile–Zambezi Basin of south western Zambia revealed high electrical resistivity anomalies (around 100 Ωm) in a low electrical resistivity (below 13 Ωm) background. The near surface (0–40 m depth range) electrical resistivity distribution of these anomalies appeared to be coincident with superficial features related to surface water such as alluvial fans and flood plains. This paper describes the application of transient electromagnetic soundings (TEM) and continuous vertical electrical sounding (CVES) using geo-electrics and time domain induced polarisation to evaluate a freshwater lens across a flood plain on the northern bank of the Zambezi River at Kasaya in south western Zambia. Coincident TEM and CVES measurements were conducted across the Simalaha Plain from the edge of the Zambezi River up to 6.6 km inland. The resulting TEM, direct current and induced polarisation data sets were inverted using a new mutually and laterally constrained joint inversion scheme. The resulting inverse model sections depict a freshwater lens sitting on top of a regional saline aquifer. The fresh water lens is about 60 m thick at the boundary with the Zambezi River and gradually thins out and deteriorates in water quality further inland. It is postulated that the freshwater lens originated as a result of interaction between the Zambezi River and the salty aquifer in a setting in which evapotranspiration is the net climatic stress. Similar high electrical resistivity bodies were also associated with other surface water features located in the airborne surveyed area.
机译:最近在赞比亚西南部马赫勒-赞比西盆地的机载TEM调查显示,在低电阻率(低于13Ωm)的背景下,高电阻率异常(约100Ωm)。这些异常的近地表(0-40 m深度范围)电阻率分布似乎与与地表水有关的表层特征(如冲积扇和洪泛区)相吻合。本文介绍了利用地电和时域感应极化的瞬变电磁测深(TEM)和连续垂直电测深(CVES)在评估南部Kasaya赞比西河北岸泛洪平原上的淡水透镜的应用赞比亚西部。从赞比西河边缘直至内陆6.6公里的整个Simalaha平原进行了TEM和CVES的同时测量。使用新的相互和横向约束的联合反演方案对得到的TEM,直流电和感应极化数据集进行反演。生成的逆模型部分描述了一个淡水透镜,该透镜位于区域盐水层的顶部。在与赞比西河交界处,淡水镜厚约60 m,逐渐变薄,内陆水质恶化。据推测,淡水晶状体是由于赞比西河与咸水层之间相互作用而产生的,在该环境中,蒸散量是净气候应力。类似的高电阻率体也与位于机载测量区域的其他地表水特征有关。

著录项

相似文献

  • 外文文献
  • 中文文献
代理获取

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号