The Continental Intercalaire (CI) aquifer, spanning Algeria, Tunisia, and Libya, is analyzed using piezometry, major ions, and stable isotopes (delta H-2, delta O-18) to track flow paths from recharge to discharge areas. A new piezometric map was generated for the CI from the interpolation of extensive datasets from the three countries (measured in 2008). A hydrochemical study was conducted on data compiled from previous investigations (n = 248 samples) and compared to new samples from this study (n = 10 samples). Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were applied to hydrochemical data transformed using the centered log ratio method. The piezometric map, created using a nested model (spherical and Gaussian variograms), achieved high accuracy (ME = 0.09 m; RMSE = 26.62 m). Variography revealed the lateral continuity of the CI aquifer over similar to 600 km, in agreement with previous studies on flow paths and recharge characteristics. Depth to groundwater is shallowest in coastal areas (similar to 20 m) and deepest in the Sahara (440 m). The hydrochemistry data show that there is a progression towards the NaCl-SO4 water type along flow paths. Compositional data analysis (CoDA) successfully differentiates similar water types, providing additional insights into CI aquifer geochemistry. Isotopes proved essential in interpreting both paleo-recharge and modern-recharge compositions, considering depletion and enrichment in delta H-2 and delta O-18 compared to the global meteoric water line (GMWL) and the paleowater line (PWL). These results are vital for sustainable water management and environmental planning.
Compositional data analysis and hydrogeochemistry of the Continental Intercalaire aquifer (northwestern Africa): A regional synthesis|非洲西北部大陆间含水层的成分数据分析和水文地球化学：区域综合研究|Données analytiques compositionnelles et hydrogéochimie de l’aquifère du Continental Intercalaire (Afrique du Nord Ouest) : une synthèse régionale|Análisis de datos composicionales e hidrogeoquímicos del acuífero Continental Intercalaire (noroeste de África): Una síntesis regional|Analisi dei dati composizionali e idrogeochimici dell’acquifero continentale intercalato (Africa nord-occidentale): una sintesi regionale|Análise de dados de composição e hidrogeoquímica do aquífero Continental Intercalaire (noroeste da África): Uma síntese regional
Pondrelli M.Penultimo
;Cavalazzi B.
2025-01-01
Abstract
The Continental Intercalaire (CI) aquifer, spanning Algeria, Tunisia, and Libya, is analyzed using piezometry, major ions, and stable isotopes (delta H-2, delta O-18) to track flow paths from recharge to discharge areas. A new piezometric map was generated for the CI from the interpolation of extensive datasets from the three countries (measured in 2008). A hydrochemical study was conducted on data compiled from previous investigations (n = 248 samples) and compared to new samples from this study (n = 10 samples). Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were applied to hydrochemical data transformed using the centered log ratio method. The piezometric map, created using a nested model (spherical and Gaussian variograms), achieved high accuracy (ME = 0.09 m; RMSE = 26.62 m). Variography revealed the lateral continuity of the CI aquifer over similar to 600 km, in agreement with previous studies on flow paths and recharge characteristics. Depth to groundwater is shallowest in coastal areas (similar to 20 m) and deepest in the Sahara (440 m). The hydrochemistry data show that there is a progression towards the NaCl-SO4 water type along flow paths. Compositional data analysis (CoDA) successfully differentiates similar water types, providing additional insights into CI aquifer geochemistry. Isotopes proved essential in interpreting both paleo-recharge and modern-recharge compositions, considering depletion and enrichment in delta H-2 and delta O-18 compared to the global meteoric water line (GMWL) and the paleowater line (PWL). These results are vital for sustainable water management and environmental planning.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
