Sequence stratigraphy petrography and age of Chilga sediments: Paleoenvironmental reconstruction of continental rift basin sediments in northwestern Ethiopia

This research presents results of an integrated approach including geochronology, paleomagnetism, petrography, x-ray diffraction analysis, depositional environment and sequence stratigraphic interpretation of Oligocene-age continental rift basin sediments. It provides a convincing analysis of the sedimentary and structural processes involved in the evolution of an Oligocene rift basin and offers inferences for both modern and ancient rift basins. The Chilga rift basin is located in northwestern Ethiopia, and it is a continental rift basin with isolated outcrops of sedimentary and volcanic basin fill separated by faults related to rift processes. Continental rift basins, such as the Chilga basin that contain outcrops which can be correlated with marker beds and that can be dated with a suitable dating method provide a unique opportunity in understanding the tectonic and stratigraphic evolution of rift basins. Paleoenvironmental reconstruction of this continental rift basin was made using correlation of marker ash beds, radioisotopic and paleomagnetic age dating, depositional environment interpretation, sequence stratigraphic interpretation, and structural analysis.