Abstract Investigations were carried out on the Tertiary sedimentary sequences from west Cameroon, namely the Mamiwater well (from 268 to 828 m), the Pungo well (from 731 to 1338 m) and the Yatou well (from 700 to 1402 m). These intervals correspond to the Souellaba Formation (SFm) of the Douala sub-basin according to the well final report produced by the National Hydrocarbons Corporation of Cameroon (NHC). The aim of this study was to characterize the lithofacies, the palynological zones, and characterize the depositional environments based on palynomorphs and palynofacies. The studied intervals are dominated by shale interbedded with limestone and siltstone; a few beds of claystone, fine to medium and coarse-grained sandstone (limited to the Pungo well) and rare marl layers are also observed. Three main palynozones were identified in each well and each zone is named. The palynological composition of the assemblages is marked by the abundance of spores and pollen grains and several stratigraphic markers in the three wells such as Cicatricosisporites dorogensis, Perigrinipollis nigericus, Proteacidites cooksonii, Zonocostites ramonae, Magnastriatites howardi, Loranthacidites nataliae, Brevicolporites molinae, Triporotetradites hookenii, Marginipollis concinnus and Adhenantheridites simplex. The dominance of the latter over dinoflagellate cysts in the Souellaba Fm indicates a high continental influence. The high percentage of angiosperms pollens grains, which are dominant in the assemblages, indicates the proximity of terrestrial sources associated with oxygenated environments. Moreover, the dominance of terrestrial palynomorphs and the relative abundance of marine palynomorphs are interpreted as indicating shallow marine environments of deposition close to terrestrial source. This marine condition is confirmed by the presence of foraminiferal test linings. The abundance of plant debris within the palynofacies indicates a climatic control on the parent vegetation and suggests the proximity to fluvial inputs. The organic matter analysis reveals type III kerogen. The relatively high number of opaque phytoclasts suggests combustion events.

中文翻译：

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Douala 子盆地的孢粉学和孢粉相分析：对 Souellaba 组/喀麦隆西部古环境演化的影响。

摘要 对喀麦隆西部第三纪沉积层序Mamiwater井（268～828 m）、Pungo井（731～1338 m）和Yatou井（700～1402 m）进行了调查。根据喀麦隆国家碳氢化合物公司 (NHC) 编制的井最终报告，这些层段对应于杜阿拉子盆地的 Souellaba 地层 (SFm)。本研究的目的是表征岩相、孢粉带，并根据孢粉体和孢粉相表征沉积环境。研究层段以灰岩、粉砂岩互层页岩为主；还观察到几层粘土岩、细粒至中粒和粗粒砂岩（仅限于 Pungo 井）和罕见的泥灰岩层。在每口井中确定了三个主要的孢粉带，并命名了每个区域。孢粉组合的孢粉组成以3口井中孢子和花粉粒丰富以及若干地层标志为特征，如Cicatricosisporites dorogensis、Perigrinipollis nigericus、Proteacidites cooksonii、Zonocostites ramonae、Magnastriatites howardi、hook Loranthacidites、Brary poranthacidites、Triple Marginipollis concinnus 和 Adhenantheridites simplex。后者在 Souellaba Fm 中的甲藻囊肿上的优势表明大陆影响很大。在组合中占主导地位的被子植物花粉粒的高百分比表明与含氧环境相关的陆地来源的接近。而且，陆地孢粉型的优势和海洋孢粉型的相对丰度被解释为表明靠近陆地源的浅海沉积环境。有孔虫测试衬里的存在证实了这种海洋条件。孢粉相内植物碎片的丰富程度表明对母本植被的气候控制，并表明接近河流输入。有机质分析揭示了 III 型干酪根。相对大量的不透明植物碎屑表明燃烧事件。孢粉相内植物碎片的丰富程度表明对亲本植被的气候控制，并表明与河流输入的接近程度。有机质分析揭示了 III 型干酪根。相对大量的不透明植物碎屑表明燃烧事件。孢粉相内植物碎片的丰富程度表明对亲本植被的气候控制，并表明与河流输入的接近程度。有机质分析揭示了 III 型干酪根。相对大量的不透明植物碎屑表明燃烧事件。