Implications of Geochemical Variables and Magnetic Susceptibility on Carbonate Levels in El-Guettiate Sebkha, Tunisia—Insights into Climate Cycles

The research aims to determine climatic cycles and the evolution of the Sebkha El-Guettiate during the last two millenniums of the Holocene by examining the regularity of chemical elements (Na, Ca and K) variables, magnetic susceptibility, Spectral analysis and carbonate percentage on a 100 cm core (SG) from the Sebkha El-Guettiate in the Skhira region of south-eastern Tunisia. The variation in the percentage of calcium carbonates in the various samples analysed along the length of the core sample shows that CaCO₃ contents are low, suggesting a chemical origin through precipitation of these carbonates. The sediments studied contained detrital, carbonate and evaporitic minerals, with a high percentage of quartz (56–98%). The chemical element results (Na, K and Ca) were mainly from halite, carbonates and gypsum, in addition to high magnetic susceptibility (MS) values. The variation in CaCO₃ concentration along the core shows significant variability. This variability is due to a radical change in the geochemistry and composition of the sediments as a result of changing climatic conditions. Spectral analysis results in this work can be performed by magnetic susceptibility and sodium shows a cycle of 1000 years and 1300 years. Significant cycles were not identified through spectral analysis of the potassium data. In addition, carbonate and calcium showed double cycles of 1600 to 860 years and 1700 to 889 years. Climate cycle factors are related to solar activity, the ocean and atmosphere.