Sedimentological and palynostratigraphy studies were used to evaluate sediment-stacking patterns in a depth range between 400 and 50 m in the Kemar-1 well section, Bornu (Chad) Basin, Nigeria. The greyish-sandy claystone, rich micaceous, lithified, and unlithified greyish claystone, dark well sorted micaceous sandstone, and poorly sorted and heterolithic clayey sandstones are the major facies components recognised in the well sections. The lithofacies characteristics were used to delineate and assign depositional environments ranging from lacustrine to fluvial settings. Paleoecological results revealed that the dominant palynofloral associations are angiosperm pollen and pteridophytic spores and they were tentatively grouped under three ecological groups which include freshwater, mangrove/brackish and savannah depositional environments in wet to dry climatic conditions during sediment formation. The presence of Echitricolporites spinosus was used to define the Echitricolporites spinosus palynological zone. The basal section at 390–385 m interval in the well shows the dominance of Psilatricolporites crassus, Verrucastosporites usmensis, and Monoporites annulatus, which marked the Eocene boundary from the overlying Miocene marker bed species of Echitricolporites spinosus, Grimsdalea magnaclavata, Anthocerus sp., Nymphaea lotus, and Retistephanocolpites gracilis. The palynomorph data and lithological characteristics from the studied well section have been used to establish that the Chad Formation is of late Eocene to early Miocene age, and that it unconformably overlies the Kerri–Kerri Formation that was deposited in varying lacustrine, fluvial and prograding shoreface and deltaic settings. This study has resolved the controversy surrounding the age of the Chad Formation, the challenge in depositional environment reconstruction. Finally, the stratigraphic framework of the Chad Formation in the study area is presented.

沉积学和孢粉地层学研究用于评估尼日利亚博尔努（乍得）盆地 Kemar-1 井段 400 至 50 m 深度范围内的沉积物堆积模式。灰砂粘土岩、富云母、岩化、未岩化灰色粘土岩、深色分选好的云母砂岩、差分选的异石质粘土砂岩是井段中识别的主要相成分。岩相特征用于描绘和分配从湖泊到河流环境的沉积环境。古生态学结果表明，主要的孢粉植物群落是被子植物花粉和蕨类植物孢子，它们暂时分为三个生态群，包括沉积物形成过程中湿到干气候条件下的淡水、红树林/咸水和稀树草原沉积环境。Echitricolporites spinosus的存在用于定义Echitricolporites spinosus孢粉学区。井内390~385 m间隔的基底剖面显示Psilatricolporites crassus、Verrucastosporites usmensis和Monoporites annulatus的优势，这标志着上新世与上新世Echitricolporites spinosus、Grimsdalea magnaclavata、Anthocerus sp.、Nymphaea等标记床种的界线。莲花和Retisstephanocolpites gracilis。研究井段的孢粉形态数据和岩性特征已被用来确定乍得组属于始新世晚期至中新世早期，并且它不整合地覆盖在不同湖泊、河流和进积岸面沉积的克里-克里组之上和三角洲设置。这项研究解决了围绕乍得组年龄的争议，即沉积环境重建的挑战。最后给出了研究区乍得组的地层格架。