Paleomagnetic directions recorded by basalts from the Khartoum Basin in Sudan of the West and Central African Rift System

Abstract We present new paleomagnetic data from basalts at Jebel Et Toriya and Jebel Fiteihab in the Omdurman area of central Sudan. These units form rare surface exposures within the Khartoum Basin, part of the eastern branch of the West and Central African Rift System, characterized by limited surface expressions of volcanism. Rock magnetic analyses indicate that the remanence is primarily carried by magnetite or titanomagnetite. Oriented block samples were collected from six sites at Jebel Et Toriya and four sites at Jebel Fiteihab, and characteristic remanent magnetization (ChRM) directions were isolated through stepwise alternating field and thermal demagnetization. The mean ChRM directions for Jebel Et Toriya ( D g = 329.1°, I g = −12.5°, k = 539.1, α 95 = 2.9°, N = 6) and Jebel Fiteihab ( D s = 347.5°, I s = −28.2°, k = 147.3, α 95 = 7.6°, N = 4, after tilt correction) yield virtual geomagnetic poles (VGPs) at 52.4°N/269.0°E ( K = 613.3, A 95 = 2.7°, N = 6) and 56.9°N/235.0°E ( K = 170.2, A 95 = 7.1°, N = 6), respectively. Neither basalt body adequately averages paleosecular variation (PSV), representing snapshots of the geomagnetic field. Nevertheless, the Jebel Et Toriya VGP lies near the Late Jurassic–Early Cretaceous cusp of the African apparent polar wander path (APWP), a similarity that may be coincidental but broadly aligns with radiometric ages (~ 145–120 Ma) reported from subsurface basalts in the Khartoum Basin. In contrast, the Jebel Fiteihab VGP aligns more closely with Late Triassic poles, possibly reflecting vertical-axis rotation associated with regional deformation linked to the Central African Shear Zone. Although the obtained VGPs are unsuitable for precise paleogeographic or APWP reconstructions due to inadequate averaging of PSV and uncertainties in age and tectonic rotations, the new data expand the sparse paleomagnetic record of the Northeast African Plate. Radiometric dating and further paleomagnetic sampling of other suitable units across the Khartoum Basin and the WCARS are essential for establishing reliable ages, assessing vertical-axis rotations, and improving the temporal and spatial resolution of the regional paleomagnetic record. Graphical Abstract