Active concomitant counterclockwise rotation and northwards translation of Africa during the Albian–Campanian time: A paleomagnetic study on the Wadi Natash alkaline volcanic province (104–78 Ma), South Eastern Desert, Egypt

Africa was a key tectonic unit in the geologic evolution of the Tethyan realm in the Middle–Late Cretaceous during the rifting of the South-Equatorial Atlantic Ocean. This research sheds light on the tectonic evolution of Africa during the Albian–Campanian time. The two end members of the Wadi Natash alkaline volcanic province [WNAVP] (104–78 Ma) in the South Eastern Desert of Egypt were studied paleomagnetically. The WNAVP (24.5° N–34.25° E) is made up of a thick succession of differentiated lava flows grading from alkali olivine basalt [AOB] followed by hawaiite–mugearite and benmoreite flows with abundant sandstone interbeds, all intruded by a large number of trachyte/phonolite [Tr/Ph] circular lava domes and ring dykes forming conspicuous landmarks in the province. The oldest flows of the AOB (104 ± 7 Ma) and the youngest Tr/Ph plugs and ring dykes (86–78 Ma) as well as the interbedded Turonian “Taref” sandstone formation [previously known as “Nubian” sandstone] were sampled all over the province which covers more than 500 km2.The isothermal remanent magnetization [IRM] study pointed to magnetite family as the major remanence in Wadi Natash volcanics, with little contribution from goethite/hematite minerals. On the other hand, goethite and/or hematite are the dominant remanence carriers in the interbedded “Taref” sandstone. After the progressive stepwise thermal demagnetization of all samples, the characteristic remanence [ChRM] direction for each rock type was visually isolated and its best-fit line was calculated, followed by the site-means, rock-unit means and the paleomagnetic poles. This paleomagnetic study revealed that:1-In the tilt-corrected coordinates, the mean ChRM of the oldest AOB flows [N = 12 sites] was Dec./Inc. = 340°/−10° [K = 54, α95 = 6º] yielding a north pole at 55° N/250° E. The ChRM of the youngest Tr/Ph ring dykes and plugs [N = 10 sites] was Dec./Inc. = 354°/3.5° [K = 60, α95 = 6.3º] yielding a north pole at 66.5° N/229° E.2-On the other hand, the site-mean ChRMs of the “Taref” sandstone interbeds [N = 8 sites], in the present-day in-situ coordinates, are clustered around the present-day geomagnetic field with a mean Dec./Inc. = 3°/33° [K = 37, α95 = 9.3°] yielding a north pole at 83° N/191° E.The two paleomagnetic poles of the AOB and the Tr/Ph are in accordance with Albian–Campanian poles from Africa [including Madagascar] and those rotated from the main Cratons such as the North American Craton, Europe [including Greenland and Iberia], South America and India using the published Plate Kinematics and Paleomagnetic Euler Pole [PEP] rotation parameters.Paleogeographically, the two obtained poles of Wadi Natash volcanics place the African Plate at two different azimuths and paleolatitudes during Albian–Cenomaniam and Santonian– Middle Campanian. Tectonically, these two paleomagnetic poles point to an active synchronous northwards translation associated with a counterclockwise rotational convergence of Africa towards Eurasia during the Albian–Campanian time. Between the time of the AOB eruption [104 ± 7 Ma] and the intrusion of the TR/Ph [86–78 Ma] Africa concomitantly rotated counterclockwise about 14° and translated northwards towards Eurasia about 6° of latitude.

► This research provides two paleotectonic positions for Africa at 104 and 86–78 Ma.
► Proves an equatorial paleotectonic position of NE Africa during Late Cretaceous.
► Reveals concurrent northward translation and CCW rotation during Late Cretaceous.
► Reveals CCW rotation convergence of Africa toward Europe in the Late Cretaceous.
► Hints the rotation of compression stress while Africa is moving toward Europe.