Topographic and subterranean structural mapping utilizing aerial magnetic and remote sensing data

Abstract

The current investigation focuses on conducting surface and subsurface structural mapping of Warana River basin’s Rafin Rewa’s warm spring area and its surroundings utilizing airborne magnetic and topographic datasets. To fulfill this objective, the residual magnetic data underwent reduction to the magnetic pole, and two methods of source edge detection were implemented: the first vertical derivative (FVD) and 3D Euler deconvolution. SRTM data was transformed into hillshade maps employing four distinct solar elevations and a constant azimuth of 450. From the FVD map, discernible structures traversing the study area were delineated, with one significant structure intersecting Rafin Rewa’s warm spring. These delineated FVD structures were superimposed on the Euler solution map with a structural index of one for further structural delineation. The Euler solutions unveiled most major structures trending in the NE-SW and NW-SE directions, with Rafin Ruwa Warm Spring located within an Euler solution cluster, suggesting its shallow-seated structural origin at depths ranging from 200 m to 400 m. Moreover, a surface structure trending NW-SE was observed to intersect Rafin Rewa’s warm spring, potentially representing a subsurface structure reflection. The magnetic structure intersecting with the topographic structure was hypothesized to be responsible for upward fluid migration, leading to the warm spring’s evolution during the Mesozoic era coinciding with the emplacement of Nigeria’s younger granite series. Statistical trend analysis revealed that 38.76% of magnetic structures trended in the NE-SW direction, followed by NNW-SSE at 33.72%, NNE-SSW at 18.22%, and NW-SE at 7.75%. Similarly, surface topographic structural trend analysis indicated that the most predominant trend was NNW-SSE at 38.57%, followed by NW-SE at 34.38%, NNE-SSW at 19.71%, WNW-ESE at 6.38%, and NE-SW at 1.05%.

Keywords

• fluid migration
• warm spring
• structural index
• warm spring and edge detection