The diagenetic evolution of sand injectite outcrops in the mixing groundwater–seawater zone of Bahrah coastal plains, northern Kuwait Bay

This qualitative and quantitative study describes the evolution of water–rock interaction processes in the groundwater–seawater mixing zone diagenetic environment associated with the development of sand injectite outcrops of the Bahrah coastal plain, northern Kuwait Bay. Fourteen rock samples were collected from the field area for petrographic analyses, X-ray diffractometry (XRD), transmitted-light microscopy (TLM), tungsten scanning electron microscopy (SEM), and cold cathodoluminescence (CL). Two groundwater samples were used for geochemical studies of bulk water chemistry properties (12 ions and salinities) and water isotope data (δ34S, δ37Cl, δ81Br, and δ13C of dissolved inorganic carbon, DIC). We found that in the mixing zone, 70% groundwater mixes with 30% seawater at shallow depths, which controls the diagenetic processes highlighted by the variability of petrographic characteristics of sand injectites in the study area.