Fluvial sediments of the middle Atbara River Valley, eastern Sudan, contain abundant vertebrate fossils and stone tools. Previous work described two sedimentary units, the Butana Bridge Synthem (BBS) and the Khashm El Girba Synthem (KGS), with three divisions each (BBS1-3 and KGS1-3, from bottom to top, respectively). ²³⁰Th/U dating on bivalve shells suggested an age of ∼126 and ∼92 ka for the basal KGS2 and basal KGS3, respectively, and mammalian biochronology in combination with magnetostratigraphy suggested an age of late Early to early Middle Pleistocene for the underlying BBS. To establish a detailed chronology of this fluvial sedimentary sequence, we collected 17 luminescence samples from both sides of the Atbara River close to the Butana Bridge. Quartz OSL dating was applied to samples from the upper part of the profile (upper KGS2 and KGS3), but the signal reached saturation within the upper ∼10 m of the sequence. To select a suitable feldspar signal to date older samples beyond the limit of the quartz OSL, a comparison of the quartz OSL, feldspar post-IR IRSL at 225 and 290 °C, and pulsed IRSL signal at 50 °C was conducted for a sample from KGS3. The result showed that only the fading corrected pulsed IRSL yielded an age consistent with the quartz OSL, and the post-IR IRSL signals (both at 225 and 290 °C) overestimated the quartz age significantly. We therefore selected the pulsed IRSL signal to date the older deposits. The luminescence ages indicate that the entire BBS - KGS sequence was deposited between 224 ± 23 ka and <17 ± 1 ka, corresponding to marine isotope stages (MIS) 7–2, significantly revising previous conclusions.

苏丹东部阿特巴拉河谷中部的河流沉积物中含有丰富的脊椎动物化石和石器。以前的工作描述了两个沉积单元，即 Butana Bridge Synthem (BBS) 和 Khashm El Girba Synthem (KGS)，每个单元分为三个部分（BBS1-3 和 KGS1-3，分别从下到上）。²³⁰双壳贝壳上的 Th/U 测年表明基底 KGS2 和基底 KGS3 的年龄分别为~126 和~92 ka，哺乳动物生物年代学与磁地层学相结合表明底层 BBS 的年龄为早早至早中更新世。为了建立这一河流沉积序列的详细年代学，我们从靠近布塔纳桥的阿特巴拉河两岸收集了 17 个发光样本。石英 OSL 测年应用于剖面上部（上部 KGS2 和 KGS3）的样品，但信号在序列上部~10 m 内达到饱和。为了选择合适的长石信号来确定超出石英 OSL 限制的较旧样品，对样品进行了石英 OSL、225 和 290 °C 的长石后 IR IRSL 和 50 °C 的脉冲 IRSL 信号的比较来自 KGS3。结果表明，只有经过衰落校正的脉冲 IRSL 产生了与石英 OSL 一致的年龄，而后 IR IRSL 信号（在 225 和 290 °C 下）显着高估了石英年龄。因此，我们选择脉冲 IRSL 信号来确定较老矿床的日期。发光年龄表明整个 BBS - KGS 序列沉积在 224 ± 23 ka 和 <17 ± 1 ka 之间，对应于海洋同位素阶段 (MIS) 7-2，显着修改了之前的结论。