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

我们基于对古元古生界深成岩中角闪石，黑云母和钾长石矿物进行的⁴⁰ Ar / ³⁹ Ar分析，介绍了西非克拉通西中部露头部分Kedougou Kenieba Inlier（塞内加尔东部）的热史。。⁴⁰氩/ ³⁹角混合和黑云母获得的Ar年龄光谱在2055±26和2028±28 Ma之间，具有非常好的一致性。他们认为，克杜古克尼巴（Kieieba Inlier）岩浆作用发生在欧本期造山运动（2.25-2.00 Ga）的末期。考虑到以前的锆石U–Pb年龄，这些新结果表明从岩浆温度到300°C（黑云母封闭温度）的初始冷却迅速发生，并且这些岩石在300°C以上没有经历任何后续的再加热事件。 。另一方面，⁴⁰ Ar / ³⁹在钾长石上获得的Ar年龄光谱显示出强烈的扰动模式，表明这些矿物由于再加热事件而经历了氩气损失。总而言之，这些数据限制了所研究区域的热历史，涉及两个热事件，温度分别在275和225°C左右，分别在1750和1500 Ma左右。这些热事件以前是根据侵入性铁镁质岩的U–Pb年龄推断的，可能与中止大陆破裂的尝试有关，因为西非克拉通在1.8–1.3 Ga间隔内仍依附于波罗的海和亚马逊克拉通。