Abstract Ashalim maze cave, and neighbouring caves in the NW Negev Desert, Israel demonstrate hypogene karst features. These features are shown to have developed as a result of the mixing of two types of groundwater flowing in opposite directions within two tiers of Cretaceous rock aquifers. The stable isotope composition indicates that the lower Kurnub sandstone aquifer was recharged over far-field Nubian Sandstone outcrops in the vicinity of the Precambrian basement outcrops of the Sinai Desert, which belongs to the Afro-Arabian dome. The water flows northward and rises into the Judea carbonate aquifer through deep faults. A similar hydrogeological system is inferred for the speleogenetic period of Ashalim Cave. Dewatering of the cave occurred in the Pliocene due to regional uplift. This is indicated by the first vadose speleothems, dated to the late Pliocene (3.1 Ma). This was followed by surface denudation, which breached the cave and formed the present entrance.

Abstract Speleothems from Ashalim Cave, located in the arid central Negev Desert, Israel, were used in a reconstruction of the palaeoclimate of the northern Saharan–Arabian desert margin. The sequence of speleothems is composed of three stratigraphic members: the yellow Pliocene Basal Member, the brown Early Pleistocene Intermediate Member and the thin Middle–Late Pleistocene Young Member. The age of the Basal Member is c. 3.1 Ma and the base of the Intermediate Member is 1.272 ± 0.018 Ma. Two last deposition periods of the Young Member occurred at 221–190 ka (Negev Humid Period (NHP) 2) and 134–114 ka (NHP-1), associated with interglacial marine isotopic stages 7.3–7.1 and 5.5, respectively. NHP-1 and -2 occurred when the African monsoon index was highest in the last 221 ka. The δ 18 O values of the speleothems range between −6.9 and −11.2‰, 2–4‰ less than in the speleothems of central and northern Israel. This may indicate a remote southern tropical source of precipitation, although during NHP-1 and -2 the thickness of the Negev Desert speleothems decreases from north to south, showing a stronger northern Mediterranean source of moisture. The δ 13 C values of the speleothems (3.5 to −8.5‰) show steppe to semi-desert C4 type vegetation. The 87 Sr/ 86 Sr ratios of the speleothems increased from c. 0.7078 in the Pliocene to 0.7082–0.7085 in the Pleistocene, indicating an increasing supply of desert dust and a decrease in host rock weathering.