Petrology and geochemistry of sandstones in the southern Benue Trough of Nigeria： Implications for provenance and tectonic setting

三个白垩纪岩石层位学的沙岩单位的 Petrographic 和 geochemical 分析被承担抑制他们的起源和构造背景。Petrographic 分析证明在在三沙岩身体之间的作文有差别，它能在起源地势，运输距离和地面的地质学被归因于差别。在古地台内部领域以内的三岩石层位学的沙岩身体下降的作文。框架模式和化学特征从玄武岩的 volcanics 显示了他们的推导，源岩在早 rifting 期间火的源岩在东南地下室建筑群地面定位了的舞台，和 felsic，中介和 mafic，与次要的沉积部件从高举并且合拢了更旧的白垩纪阶层。沙岩的化学成分主要与源岩，化学捱过条件和运输代理人有关。源岩主要从尼日利亚的东南的前寒武纪的地下室被导出。通过沙岩的检查，构造背景被建模。Benue 马槽属于被动边缘的沉积的盆打的一个大陆人。到马槽的 Maastrichtain 的从 Albian 的构造进化被贡献在框架模式和沙岩的化学成分的差别。盆的进化以沙岩岩石学和地球化学被重建。构造进化能从岩石学和地球化学数据被细分进三个阶段。第一个阶段盖住 Albian；第二上演 Turonian-Coniacian，并且第三上演 Campanian-Maastrichtain。这些是在在这三个阶段之中的沙岩作文的三大断绝。这三断绝意味着 tectonism 的影响。

Petrographic and geochemical analyses of three Cretaceous lithostratigraphic sandstone units were undertaken to constrain their provenance and tectonic setting. Petrographic analysis showed that there are differences in composition between the three sandstone bodies, which can be attributed to differences in provenance relief, transport distance and geology of the terrain. Composition of the three lithostratigraphic sandstone bodies fall within the craton interior field. Framework mode and chemical features indicated their derivation from basaltic volcanics, source rocks during the early rifting stage, and felsic, intermediate and mafic igneous source rocks located at the southeast basement complex terrain, with minor sedimentary components from the uplifted and folded older Cretaceous strata. The chemical composition of the sandstones is mainly related to source rocks, chemical weathering conditions and transport agents. The source rocks were derived mainly from the southeastern Precambrian basement of Nigeria. Through examination of the sandstones, the tectonic setting was modeled. The Benue Trough belongs to a continental sedimentary basin of the passive margin type. The tectonic evolution from Albian to Maastrichtain of the trough is contributed to the difference in framework mode and chemical composition of the sandstones. The evolution of the basin was reconstructed in terms of sandstone petrology and geochemistry. The tectonic evolution can be subdivided into three stages from the petrology and geochemistry data. The first stage covers Albian; the second stage the Turonian-Coniacian, and the third stage the Campanian-Maastrichtain. These are the three mega discontinuities in the sandstone composition among these three stages. These three discontinuities signify the influence of tectonism.