MAPPING GROUNDWATER RECHARGE ZONES AND LITHOLOGY WITHIN A MOUNTAINOUS HEADWATER CATCHMENT AREA OF THE SNOWY RANGE NEAR LARAMIE, WY WITH AIRBORNE ELECTROMAGNETIC AND MAGNETIC DATA

2014 ◽  
Author(s):  
Bradley Carr ◽  
Ryan Armstrong ◽  
W. Steven Holbrook ◽  
Jesper Pedersen ◽  
Esben Auken
Keyword(s):  
Groundwater Recharge ◽  
Catchment Area ◽  
Magnetic Data ◽  
Airborne Electromagnetic ◽  
Snowy Range ◽  
Headwater Catchment

scholarly journals Simplicity versus complexity in modelling groundwater recharge in Chalk catchments

2002 ◽  
Vol 6 (5) ◽  
pp. 927-937 ◽  
Author(s):  
R. B. Bradford ◽  
R. Ragab ◽  
S. M. Crooks ◽  
F. Bouraoui ◽  
E. Peters
Keyword(s):  
Groundwater Recharge ◽  
Input Data ◽  
River Flow ◽  
Climatic Conditions ◽  
Soil Types ◽  
Flow Data ◽  
Catchment Scale ◽  
Distributed Models ◽  
Headwater Catchment ◽  
Simple Models

Abstract. Models of varying complexity are available to provide estimates of recharge in headwater Chalk catchments. Some measure of how estimates vary between different models can help guide the choice of model for a particular application. This paper compares recharge estimates derived from four models employing input data at varying spatial resolutions for a Chalk headwater catchment (River Pang, UK) over a four-year period (1992-1995) that includes a range of climatic conditions. One model was validated against river flow data to provide a measure of their relative performance. Each model gave similar total recharge for the crucial winter recharge period when evaporation is low. However, the simple models produced relatively lower estimates of the summer and early autumn recharge due to the way in which processes governing recharge especially evaporation and infiltration are represented. The relative uniformity of land use, soil types and rainfall across headwater, drift-free Chalk catchments suggests that complex, distributed models offer limited benefits for recharge estimates at the catchment scale compared to simple models. Nonetheless, distributed models would be justified for studies where the pattern and amount of recharge need to be known in greater detail and to provide more reliable estimates of recharge during years with low rainfall. Keywords: Chalk, modelling, groundwater recharge

Interpolation and gridding of aliased geophysical data using constrained anisotropic diffusion to enhance trends

Geophysics ◽  
2005 ◽  
Vol 70 (5) ◽  
pp. V121-V127 ◽  
Author(s):  
Richard S. Smith ◽  
Michael D. O'Connell
Keyword(s):  
Diffusion Process ◽  
Anisotropic Diffusion ◽  
Data Grid ◽  
Geophysical Data ◽  
Magnetic Data ◽  
Electromagnetic Data ◽  
Sampling Intervals ◽  
Airborne Electromagnetic ◽  
Sample Interval ◽  
Airborne Electromagnetic Data

Geophysical data are frequently collected with a fine sample interval along traverse lines but with a coarser sampling in the direction perpendicular to the traverses. This disparity in sampling intervals is particularly evident when magnetic data are collected simultaneously with airborne electromagnetic data. Interpolating this traverse data onto an evenly spaced 2D grid can result in aliasing artifacts. For example, narrow linear structures that trend at acute angles to the traverse lines are imaged as a thick/thin/thick feature, looking like a boudinage or string of beads. Applying the anisotropic diffusion process to the resulting grids of data removes the artifacts, but the grid values close to the traverses are altered significantly from their initial values. The altered values are therefore not faithful to the original traverse data. The anisotropic diffusion algorithm can be modified to constrain values close to the original traverses. This modification removes the aliasing artifacts and produces a data grid faithful to the original traverse data. Some small artifacts along the traverse lines in the final data grid become more evident when grids containing derivative data (such as the analytic signal) are generated from the new data grid. However, these small traverse-line artifacts can be removed with standard microleveling procedures. The constrained anisotropic diffusion process is iterative, and some experimentation is required to determine the appropriate number of iterations.

Quantifying aggregation and change in runoff source in accordance with catchment area increase in a forested headwater catchment

2016 ◽  
Vol 30 (22) ◽  
pp. 4125-4138 ◽  
Author(s):  
Tomohiro Egusa ◽  
Nobuhito Ohte ◽  
Tomoki Oda ◽  
Masakazu Suzuki
Keyword(s):  
Catchment Area ◽  
Area Increase ◽  
Headwater Catchment

scholarly journals Application of Airborne Electromagnetics and Magnetics for Mineral Exploration in the Baishiquan–Hongliujing Area, Northwest China

2021 ◽  
Vol 13 (5) ◽  
pp. 903
Author(s):  
Shengjun Liang ◽  
Siyuan Sun ◽  
Hongfei Lu
Keyword(s):  
High Efficiency ◽  
Mineral Exploration ◽  
Northwest China ◽  
Ore Deposits ◽  
Gansu Province ◽  
Integrated System ◽  
Magnetic Data ◽  
Airborne Electromagnetic ◽  
Airborne Electromagnetics ◽  
Airborne Magnetic

Airborne electromagnetics is an effective and efficient exploration tool in shallow mineral exploration for its high efficiency and low cost. In 2016, airborne electromagnetic and airborne magnetic surveys have been carried out at the border of Xinjiang Uygur Autonomous Region and Gansu Province, the Northwest China. With an integrated system, the airborne electromagnetics and airborne magnetic data were collected simultaneously by AreoTEM-IV system from Aeroquest International Limited in Vancouver, BC, Canada, and the CS3 Cesium Vapor magnetometer from Scintrex in Concord, ON, Canada. About 3149 line-km of both data with 250 m line space were acquired. After data processing, the comprehensive analysis and interpretation of resistivity and magnetic anomalies has been carried out to infer lithological structure and outline the potential ore deposits. Verified by the ground surveys, seven outlined anomalies are consistent with the known ore sites, and one new gold deposit and several mineralization clues were found. The prospective reserves of gold are expected to exceed 10 tons. Besides, some prospecting target areas were outlined as the possible locations of copper–nickel deposits. The successful case shows the airborne magnetic data accords with geological structures, and the airborne electromagnetic method is effective in finding metal mineral resources, which can help to quickly identify potential ore targets with no surface outcrop.

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