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Reconstructing 2000-Year, Oceanic Temperature Changes off Southwest Morocco Using G. bulloides Foraminifera Mg/Ca Ratios

This study was conducted on the GeoB8601-3 core, collected off the southwest coast of Morocco, to reconstruct the variations in oceanic temperatures over the past 2000 years. Geochemical analyses of planktonic foraminifera G. bulloides in the core provided Mg/Ca ratios, as well as stable carbon (δ13C) and oxygen (δ18O) isotopes. The distribution of Mg/Ca ratios with respect to core depth exhibited significant variations, with the lowest values recorded at a depth of 90-91.5 cm and the highest values observed at depths of 110-111.5 cm and 135-136.5 cm. Through specific calibrations, Mg/Ca values were converted to temperatures, allowing for the reconstruction of oceanic temperatures off southwest Morocco over the 2000-year period. The results indicated a significant temperature increase during certain periods, particularly between ±2112 and ±1681 years BP, as well as between ±1191 and 233 years BP. Relatively cooler temperatures were observed from approximately 165 years BP to the present, with a notable cooling event around 1351 years BP. Comparative analysis of the records obtained, through the two calibration methods, revealed a general trend of decreasing sea surface temperatures over the past 2000 years. It is important to note that these findings are based on the specific study of the GeoB8601-3 core and G. bulloides foraminifera. Further research and additional data are necessary to confirm these observations and gain a better understanding of oceanic temperature variations in this region during the studied period.

Southwest Morocco, Oceanic Temperatures, Mg/Ca Ratios, G. bulloides Foraminifera, Reconstruction, Last 2000 Years

Jawad El Hawari, Mohamed El Ghachi. (2023). Reconstructing 2000-Year, Oceanic Temperature Changes off Southwest Morocco Using G. bulloides Foraminifera Mg/Ca Ratios. Advances, 4(4), 116-123.

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