Basement Configuration and Tectonic Evolution Beneath Zallah Trough, Western Sirt Basin, Libya, Obtained from Integrated Gravity, and Aeromagnetic Data

Abstract

In this study, gravity and aeromagnetic datasets are analysed to map fault systems and the depth of the basement, which has hitherto been unknown. The gravity and magnetic data were provided by the Libyan Petroleum Institute. Low-pass filters separated local and regional components of gravity and aeromagnetic datasets, as well as the CET grid analysis filter, Euler deconvolution, Source Parameter Imaging (SPI) estimate of crystalline basement depth, Werner deconvolution, and 2D forward modelling. The results show the fault patterns, primarily trends, are NE-SW, N-S, and NW-SE, which define and constrain the trough. Some structural characteristics in the centre and southern trough have an NNE-SSW orientation with estimated depth ranging from (400 to 5350) m as resulted by Euler deconvolution. The SPI technique estimates the crystalline basement at about 5200 m. The Werner solution showed volcanic bodies in the form of sills; in addition, it approved that these volcanic bodies have depths of 4366m and 5067 m, respectively. Thle observed sill bodies may have been the result of the Sirt Basin rifting, causing a weakening of the crust to allow mantle flow. The 2D modelling showed that the depth of the basement ranges between (5100 and 5400) m beneath the depocenter of the study area.