ABSTRACT The influence of lithology on morphological variability across space presents a unique approach to understand how morphological variables and domain units respond to lithological variations. This study examines variation existing in channel morphological variables across domain units within a basement complex. Eighty-three reaches were surveyed across six third-order basins within the Upper Ogun River basin, Nigeria. Each of the six third-order basins is heterogeneously underlain by various lithological formations. Fourteen morphological variables (bankfull; depth, width, cross-sectional area, width-depth ratio, wetted perimeter, hydraulic radius, discharge, total stream power, specific stream power, shear stress, velocity, dimensionless stream power, Darcy-Weisbach friction factor and channel gradient) were measured and estimated across the 83 reaches. Analysis of Variance revealed that significant variation occurs in channel morphological properties between schist and granite and between granite and migmatite. Also, bankfull width showed exponent values of wbf ~ Qbf 0.21 for migmatite; wbf ~ Qbf 0.11 for granites; and wbf ~ Qbf 0.34 for schists. Channel unit sequence using Markov chain presents two transitions identified as bedrock to plane-bed and step-pools to plane-bed. The absence of transitions as observed is closely tied to the occurrence of non-cyclic patterns.

中文翻译：

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尼日利亚西南部上奥贡河流域与岩性控制相关的小型基岩和冲积河道的形态和水力变化

摘要 岩性对跨空间形态变异的影响提供了一种独特的方法来了解形态变量和域单元如何响应岩性变化。这项研究检查了地下室复合体中跨域单元的通道形态变量中存在的变化。在尼日利亚上奥贡河流域的六个三阶流域中对 83 个河段进行了调查。六个三级盆地中的每一个都被各种岩性地层不均匀地下伏。十四个形态变量（满岸；深度、宽度、横截面积、宽深比、湿周、水力半径、流量、总流功率、比流功率、剪切应力、速度、无量纲流功率、Darcy-Weisbach 摩擦系数和渠道梯度）在 83 个河段中进行了测量和估计。方差分析表明，片岩和花岗岩之间以及花岗岩和混合岩之间的通道形态特征发生了显着变化。此外，bankfull width 显示混合岩的 wbf ~ Qbf 0.21 的指数值；wbf ~ Qbf 0.11 花岗岩；片岩的 wbf ~ Qbf 为 0.34。使用马尔可夫链的河道单元序列呈现了两个被确定为基岩到平面床和阶梯池到平面床的过渡。观察到的过渡的缺失与非循环模式的发生密切相关。bankfull width 显示混合岩 wbf ~ Qbf 0.21 的指数值；wbf ~ Qbf 0.11 花岗岩；片岩的 wbf ~ Qbf 为 0.34。使用马尔可夫链的河道单元序列呈现了两个被确定为基岩到平面床和阶梯池到平面床的过渡。观察到的过渡的缺失与非循环模式的发生密切相关。bankfull width 显示混合岩 wbf ~ Qbf 0.21 的指数值；wbf ~ Qbf 0.11 花岗岩；片岩的 wbf ~ Qbf 为 0.34。使用马尔可夫链的河道单元序列呈现了两个被确定为基岩到平面床和阶梯池到平面床的过渡。观察到的过渡的缺失与非循环模式的发生密切相关。