Stratigraphic framework of the northeastern part of the Ethiopian flood basalt province

We present a first stratigraphy of the flood basalt succession in eastern Wollo province, northern Ethiopian plateau, based on detailed field logging. This study was initiated to resolve outstanding issues in the region regarding the timing and extent of flood volcanism, assisting a wider correlation of stratigraphic sequences across the Ethiopian plateau. Our approach involved construction of stratigraphic sections from six selected gorge localities having ~ 100% exposure. Individual flow thickness, lithology, and sequence were recorded at each locality. Features common to all localities indicate a single magmatic plumbing system for the mapped area. Three formations are identified and named, and linked to published Oligocene radiometric ages from neighboring areas. These formations are from base to top: Teri Basalt, the main phase of flood basalt emission, is conformably overlain by the Wegeltena Rhyolite, composed of silicic ignimbrites dated at ~ 30.2 Ma. Upon this rests a thin bed of conglomerate, sandstone, and mudstone representing a ~ 3 Ma episode of volcanic quiescence. At the top of the sequence lies the Kon Basalt, dated at 27.8–26.7 Ma. Comparison of this new stratigraphy with other Oligocene sequences on the northern plateau reveals significant variations in lithology and age range, with implications for how the Ethiopian flood basalt province was constructed. More work is required in seeking the fissure vents and their geometry.