Geochemical characterisation of Early Cretaceous lacustrine sediments of Bima Formation, Yola Sub-basin, Northern Benue Trough, NE Nigeria: Organic matter input, preservation, paleoenvironment and palaeoclimatic conditions
Geochemical characterisation of Early Cretaceous lacustrine sediments of Bima Formation, Yola Sub-basin, Northern Benue Trough, NE Nigeria: Organic matter input, preservation, paleoenvironment and palaeoclimatic conditions
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DOI：
10.1016/j.marpetgeo.2014.12.010
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发表时间：
2015-03
影响因子：
4.2
通讯作者：
B. Yandoka;W. Abdullah;M. Abubakar;M. Hakimi;A. Adegoke
中科院分区：
文献类型：
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作者：
B. Yandoka;W. Abdullah;M. Abubakar;M. Hakimi;A. Adegoke
碧马组是贝努埃海槽北部约拉凹陷白垩纪层序底部最古老的成岩单元。它分为下(B1)、中(B2)和上(B3)BIMA成员。对碧马组湖相沉积进行了有机和无机综合地球化学研究，旨在恢复古沉积环境和有机质输入，以响应气候和构造作用。所分析的沉积物是在淡水湖泊环境中沉积的，具有低盐度分层水柱和亚缺氧至相对缺氧的条件，如主体地球化学参数所示。生物标志物为水生藻类和微生物的贡献提供了证据，并提供了大量陆源有机质输入。有机质的保存可能是由于低盐度的分层水柱和相对缺氧的亚缺氧条件所致。根据常量元素和微量元素的地球化学特征，沉积物形成于半干旱气候条件下的被动大陆边缘环境。这与早白垩世西非和中非裂谷系统(WCARS)的构造事件相吻合。
The Bima Formation is the oldest lithogenetic unit occupying the base of the Cretaceous successions in the Yola Sub-basin of the Northern Benue Trough. It is differentiated into Lower (B1), Middle (B2) and Upper (B3) Bima Members. Integrated organic and inorganic geochemical studies were applied on the lacustrine sediments of the Bima Formation with the aim of reconstructing the palaeodepositional environment and organic matter input in response to climate and tectonism. The analysed sediments were deposited in a freshwater lacustrine environment with a low-salinity stratified water column and suboxic to relatively anoxic conditions, as indicated by the bulk geochemical parameters. The biomarkers provide evidence for a contribution of aquatic algae and microorganisms, with a significant amount of terrigenous organic matter input. The preservation of the organic matter is possibly attributed to the stratified water column with low salinity and suboxic to relatively anoxic conditions. Based on the geochemistry of major and trace elements, the sediments were deposited during semi-arid climatic conditions within passive continental margin setting. This agrees with the tectonic events in the West and Central African Rift System (WCARS) during the Early Cretaceous period.