IMAGING THE MOHO AND CONRAD CRUSTAL DISCONTINUITY USING THE SPECTRAL ANALYSIS WITH PIECEWISE REGRESSION OF GRAVITY DATA

This study explored the satellite gravity data mapping the lithospheric structure beneath the Okavango Rift Zone (ORZ) in northwest Botswana and Kafue Rift Zone (KRZ) in Zambia. The tectonic extent and subsurface lithospheric structures are well known for the ORZ in Botswana; however, less study has been found on the KRZ in Zambia, and lithospheric control is poorly constrained. This study addresses the relationship between these rift systems to image the details of the topography of the Moho and the Precambrian crystalline basement. Determining the depth of Moho within this region will bridge the knowledge of subsurface lithospheric control between the Okavango and Kafue rift zone. We use Spectral Analysis with Piecewise Regression (SAPR) of the World Gravity Model 2012 (WGM 2012) to estimate the depth of the Moho and the Precambrian crystalline basement beneath the Okavango and Kafue rift. The Moho depth estimates of the SAPRA analysis showing the crustal thickness varies between 26 km to 36 km for the Kafue rift zone, whereas the crustal thickness of the Okavango rift zone varies between 20 km to 32 km. In addition, we compare the result with two-dimensional (2D) forward modeling of the same gravity data to identify lithospheric structures beneath the rift systems. This study enables us to compare the newly studied Kafue rift system with the other more evolved branches of the EARS to develop a more comprehensive model for the East African Rift System.