Abstract This paper documents the detailed sedimentology and stratigraphic evolution of the Sandy members of the Pindiga Formation. Good understanding of this succession is relevant to resource exploration and exploitation in the frontier Gongola Sub-basin of the Northern Benue Trough and similar Cretaceous strata in general. Detailed facies analysis based on examination of twelve well exposed outcrops revealed four facies successions. Field relations show that the deposits are stratigraphically partitioned by a disconformity surface into two parts. The lower part consists of regressive wave-storm dominated deltaic and wave-storm dominated offshore to nearshore facies successions, while the upper part comprises of transgressive wave dominated estuary and tide dominated estuary successions. Fourteen facies were identified and organized into nine facies associations. Field observations show that the upper boundary of the Sandy members is an angular unconformity represented by the development of a thick paleosol unit below the Fika Shale. Conversely, the lower boundary is transitional. Contrary to earlier fluvial and coastal to littoral interpretation of the Sandy members, this work demonstrates that marine processes were important for facies development. It is shown that an integration of detailed facies and ichnological analyses is valuable in determining robust paleoenvironmental interpretations of sedimentary successions.

中文翻译：

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尼日利亚贝努埃海槽北部 GONGOLA 子盆地 Pindiga 组沙质成员的沉积学和地层发育：混合波、潮汐和河流影响的海岸系统

摘要 本文记录了 Pindiga 组 Sandy 段的详细沉积学和地层演化。对这一层序的深入了解，对于贝努埃海槽北部贡戈拉次盆地和一般白垩纪类似地层的资源勘探开发具有重要意义。基于对十二个出露良好的露头的检查的详细相分析揭示了四个相序列。现场关系表明，沉积物在地层上被一个不整合面分成两部分。下部为海退波浪为主的三角洲和波浪为主的近岸相系列，上部为海进波浪主导的河口和潮汐主导的河口系列。确定了 14 种相并将其组织成 9 种相协会。野外观测表明，桑迪段上界是一个角不整合面，以菲卡页岩下方厚层古土壤单元发育为代表。相反，下边界是过渡性的。与早期对桑迪成员的河流和沿海到沿海的解释相反，这项工作表明海洋过程对相发展很重要。结果表明，详细的相和地质学分析的整合对于确定沉积层序的稳健古环境解释是有价值的。下边界是过渡性的。与早期对桑迪成员的河流和沿海到沿海的解释相反，这项工作表明海洋过程对相发展很重要。结果表明，详细的相和地质学分析的整合对于确定沉积层序的稳健古环境解释是有价值的。下边界是过渡性的。与早期对桑迪成员的河流和沿海到沿海的解释相反，这项工作表明海洋过程对相发展很重要。结果表明，详细的相和地质学分析的整合对于确定沉积层序的稳健古环境解释是有价值的。