Several attempts at reconstructing geological settings and palaeoclimatic changes of the siliciclastic deposits of the Dahomey Basin, SW Nigeria, using relative age dating and correlation methods, have resulted in serious discrepancies on the ages. Therefore, a chronology framework established by an absolute age dating method is requisite to constrain the geological interpretation. This research focuses on quartz optically stimulated luminescence (OSL) dating of the upper siliciclastic sediments to help bridge the lacuna that arose from previous relative geologic dating. Ten sub-surface sediment samples were collected from the eastern part of the basin, and quartz OSL dating using single-aliquot regenerative-dose protocol was conducted for all the samples. The OSL signals appear well bleached prior to deposition and the OSL ages are reliable and robust. Through the application of OSL, the age framework of the uppermost part of sediments in the study area was established. The OSL dating results revealed that these depositional periods fall within the Holocene and are concentrated during two groups: 3.52 ka–1.55 ka, and 0.64 ka–0.05 ka. The samples with ages of 3.52 ka–1.55 ka distribute in the belt-like inland zone approximately parallel to the coastline. This deposition episode appears to be caused by the decrease in relative sea level during late Holocene. Thus, this study sheds light on the understanding past coast dynamics in the region.

使用相对年龄和相关方法重建尼日利亚西南部达荷美盆地硅质碎屑沉积物的地质背景和古气候变化的几次尝试导致了严重的年龄差异。因此，通过绝对年代学方法建立的年代学框架是约束地质解释的必要条件。这项研究的重点是对上层硅质碎屑沉积物进行石英光学受激发光 (OSL) 测年，以帮助弥合先前相对地质测年产生的空隙。从盆地东部收集了 10 个地下沉积物样品，并对所有样品进行了使用单等分再生剂量方案的石英 OSL 测年。OSL 信号在沉积之前看起来很好地漂白，并且 OSL 年龄是可靠和稳健的。通过OSL的应用，建立了研究区沉积物最上部的年龄框架。OSL 测年结果显示，这些沉积时期属于全新世，集中在两组：3.52 ka–1.55 ka 和 0.64 ka–0.05 ka。年龄为3.52 ka～1.55 ka的样品分布于与海岸线大致平行的带状内陆带。这种沉积事件似乎是由全新世晚期相对海平面下降引起的。因此，这项研究阐明了对该地区过去海岸动态的理解。OSL 测年结果显示，这些沉积时期属于全新世，集中在两组：3.52 ka–1.55 ka 和 0.64 ka–0.05 ka。年龄为3.52 ka～1.55 ka的样品分布于与海岸线大致平行的带状内陆带。这种沉积事件似乎是由全新世晚期相对海平面下降引起的。因此，这项研究阐明了对该地区过去海岸动态的理解。OSL 测年结果显示，这些沉积时期属于全新世，集中在两组：3.52 ka–1.55 ka 和 0.64 ka–0.05 ka。年龄为3.52 ka～1.55 ka的样品分布于与海岸线大致平行的带状内陆带。这种沉积事件似乎是由全新世晚期相对海平面下降引起的。因此，这项研究阐明了对该地区过去海岸动态的理解。