The limitation of the gravity inversion method based on the Parker-Oldenburg algorithm in determination of the basement topography

By: Chikondi Chisenga, Emmanuel Chinkaka,

Abstract

This short communication discusses a 2013 publication by Oruç et al., (2013) who presented a structural interpretation map of the Erzurum Basin in eastern Turkey using curvature gradient tensor, and inferred the basement topography using gravity inversion method. In our comment, we show the limitation of the gravity data they used and the flawed approach in determining the basement topography. The gravity data were not filtered to remove deeper sources, which subsequently resulted in two interfaces, the Moho and the interface between crystalline basement and sedimentary sequences. Multi- interface gravity data are not ideal for a single interface determination in the inversion, as shown from our discussion. Finally, we applied the approach used by Oruç et al., (2013) in the Lower Shire Basin, Southern Malawi to determine the effect of the inversion in a similar environment. The results showed that even in areas where basement is exposed, deeper basement values of greater than 3 km are resolved. Thus, the limitation of this approach is not specific to Erzurum Basin in Turkey, but also true to other sedimentary basinsThis short communication discusses a 2013 publication by Oruç et al. (2013) who presented a structural interpretation map of the Erzurum Basin in eastern Turkey using curvature gradient tensor, and inferred the basement topography using gravity inversion method. In our comment, we show the limitation of the gravity data they used and the flawed approach in determining the basement topography. The gravity data were not filtered to remove deeper sources, which subsequently resulted in two interfaces, the Moho and the interface between crystalline basement and sedimentary sequences. Multi- interface gravity data are not ideal for a single interface determination in the inversion, as shown from our discussion. Finally, we applied the approach used by Oruç et al. (2013) in the Lower Shire Basin, Southern Malawi to determine the effect of the inversion in a similar environment. The results showed that even in areas where basement is exposed, deeper basement values of greater than 3 km are resolved. Thus, the limitation of this approach is not specific to Erzurum Basin in Turkey, but also true to other sedimentary basins