Deciphering aeromagnetic data for sustainable sedimentary and structural insights in Obudu Plateau, Ikom Mamfe embayment and Oban Massif, southeastern Nigeria

Abstract

Aeromagnetic data acquired over the Obudu Plateau, Ikom Mamfe embayment, and Oban Massif was analyzed to evaluate the study area's structural pattern and sedimentary thickness. Data filtering and other enhancement methods with 2-D forward modeling were applied to total magnetic intensity (TMI) data to evaluate the structural pattern, possible mineralization potential, sedimentary thickness, and basement framework disparity. To achieve this aim, several data enhancement techniques such as first vertical derivative (FVD), second vertical derivative (SVD), total horizontal derivative (THD), tilt angle derivative (TAD), analytic signal (AS), upward continuation (UC), low pass filter (LPF), high pass filter (HPF), Centre for Exploration Targeting (CET) and 2-D forward modeling were performed on the TMI data from which the buried subsurface structural lineaments and trends were unraveled. The structural lineaments delineated from the various enhancement operations revealed the major structural orientations of NE-SW. In contrast, the minor geologic structures trend in NNE-SSW, NW-SE, N-S, and E-W directions. These high frequency magnetic anomalies (geologic structures) are caused by post-depositional magmatic intrusions occurring at shallow depth and they have significant control over mineralization. They serve as migration pathways for hydrothermal fluids and accumulation zones for minerals. The depth estimation techniques like source parameter imaging (SPI), standard Euler deconvolution (SED) and 2D forward modelling employed in this study, revealed predominantly shallow depths (< 1400 m). These thin sedimentations are attributed to the widespread presence of Precambrian basement rocks in the Oban Massif and Obudu Plateau as well as the significant basaltic intrusions of Ikom-Mamfe Embayment. Furthermore, the 2-D forward model along the SW-NE profile revealed sediment thickness of 0-700 m overlying intruded metamorphic basement with magnetic susceptibility values ranging from 0.00001 to 0.00625 SI. The model which is highly undulant, revealed two sub-basins separated by the magmatic intrusion.