Proterozoic magmatic events recorded in 40Ar/39Ar data from the northern part of the Kedougou Kenieba Inlier (eastern Senegal)

Abstract We present a thermal history of the Kedougou Kenieba Inlier (eastern Senegal), western-central outcropping part West African Craton, based on 40Ar/39Ar analyses performed hornblende, biotite, and K-feldspar minerals from Paleoproterozoic plutonic rocks. age spectra obtained for hornblendes biotites range between 2055 ± 26 2028 ± 28 Ma, in very good consistency. They suggest that magmatism happened at end Eburnean Orogeny (2.25–2.00 Ga). Taking into account previous zircon U–Pb ages, these new results imply initial cooling magmatic temperature to about 300 °C (biotite closure temperature) occurred rapidly, rocks did not experience any subsequent re-heating event above 300 °C. On other hand, K-feldspars display strongly disturbed patterns revealing experienced argon loss due events. Altogether, data constrain studied area involving two events with temperatures around 275 225 °C, 1750 1500 Ma, respectively. These events, previously inferred ages intruding mafic dykes, can be related aborted attempts continental breakup, as Craton remained attached Baltica Amazonia cratons during 1.8–1.3 Ga interval.