The groundwater quality of Tadjenanet- Chelghoum Laid Semi-arid region was assessed for irrigation suitability; where the intensity of salinization process depends on soil characteristics, water quality, irrigation practices and in particular the inefficiency of the drainage system. The drought of the last decade has created an agricultural deficit due to high evapotranspiration, influencing the water salinity. To achieve this assessment, thirty groundwater samples were collected at identical locations from deeper wells. The physicochemical parameters such as, pH, electrical conductivity (EC), total hardness (TH), Ca²^+$, Mg²^+$, Na^+$, K^+$, HCO3^-$, SO4²^-$, Cl^-$ and NO3^-$ have been studied. Obtained results were measured and interpreted with different irrigation indexes like EC, sodium percentage (SP), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), permeability index (PI) and Kelly’s ratio (KR). These parameters combined allowed to conclude that the quality of groundwater was roughly suitable for irrigation.

The Algero-Tunisian confines (Tebessa region) is partially composed of Cenomano- Turonian carbonate outcrops; therefore, it presents a good example to highlight the black shale levels reported over a short period, around the Cenomanian-Turonian boundary. The lithostratigraphic study made it possible to specify the paleoenvironment during the Cenomano-Turonian in the Tebessa region. At that time, the depositional environment emphasized a relatively deep, calm and often confined ocean environment that was significantly shalloweron the north part of the study area. The lithology and the distribution of the facies in the Constantine domain allow us to underline the pelagic influences during the Upper Cretaceous and neritic during the lower Cretaceous period. We note a maximum thickness of the Cenomano- Turonian in the southern zones and a minimum (100m) appears further north. This Palaeogeographic organization continue laterally in Tunisia on the extension of the Constantine mole.

The Algero-Tunisian confines (Tebessa region) is partially composed of Cenomano- Turonian carbonate outcrops; therefore, it presents a good example to highlight the black shale levels reported over a short period, around the Cenomanian-Turonian boundary. The lithostratigraphic study made it possible to specify the paleoenvironment during the Cenomano-Turonian in the Tebessa region. At that time, the depositional environment emphasized a relatively deep, calm and often confined ocean environment that was significantly shalloweron the north part of the study area. The lithology and the distribution of the facies in the Constantine domain allow us to underline the pelagic influences during the Upper Cretaceous and neritic during the lower Cretaceous period. We note a maximum thickness of the Cenomano- Turonian in the southern zones and a minimum (100m) appears further north. This Palaeogeographic organization continue laterally in Tunisia on the extension of the Constantine mole.

The Algero-Tunisian confines (Tebessa region) is partially composed of Cenomano- Turonian carbonate outcrops; therefore, it presents a good example to highlight the black shale levels reported over a short period, around the Cenomanian-Turonian boundary. The lithostratigraphic study made it possible to specify the paleoenvironment during the Cenomano-Turonian in the Tebessa region. At that time, the depositional environment emphasized a relatively deep, calm and often confined ocean environment that was significantly shalloweron the north part of the study area. The lithology and the distribution of the facies in the Constantine domain allow us to underline the pelagic influences during the Upper Cretaceous and neritic during the lower Cretaceous period. We note a maximum thickness of the Cenomano- Turonian in the southern zones and a minimum (100m) appears further north. This Palaeogeographic organization continue laterally in Tunisia on the extension of the Constantine mole.