69-8 Holocene Climate Variability and Hydrological Shifts Inferred from C/N Ratios in Wadi El-Natrun Lakes, Western Nile Delta

Session: Joint SGD-SEPM-IAS Focus on the Sedimentary Record of Climate Change (Posters)

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Examining Holocene environmental and climatic shifts in the Nile Delta region—and their relationship to patterns of human settlement—offers critical insights into natural climate variability, contemporary environmental processes, and potential future climate scenarios. Despite the Nile’s long-standing role as a dynamic interface between civilizations, desert landscapes, and fluvial systems, high-resolution studies of its surrounding desert areas remain scarce. In this study, two sediment cores were extracted near lakes in the Wadi El-Natrun region, located in the western Nile Delta of Egypt. These cores were analyzed at 5 cm intervals for total organic carbon (TOC) and carbon-to-nitrogen (C/N) ratios. 

Nitrogen concentrations in the sediments of both cores were consistently low (below 1 wt%), often falling beneath the instrument’s detection limit. Organic carbon levels were similarly low in one core (below 1 wt%, with a single exception), while the other core exhibited a broader range, from 0.10 to 2.97 wt%, aside from one anomalous sample at 18.79 wt%. Variations in C/N ratios across both cores suggest shifts in the type of organic matter, likely driven by episodic fluctuations in rainfall and corresponding changes in water levels. Elevated water levels would have supported microplankton blooms, resulting in lower C/N ratios, whereas higher ratios point to drier conditions. These sedimentary changes reflect the interplay between climatic variability and evolving depositional environments. Forthcoming carbon-14 dating will help pinpoint the timing of these transitions and potentially correlate them with established global paleoclimate events. Collectively, these findings contribute to a more integrated understanding of Holocene climate dynamics and environmental evolution in the Nile Delta. 

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-11176

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