[en] ¹⁴C-, ³H and stable isotope analyses were done on Libyan waters from wells in the Wadi Sawfajjin-Wadi Zamzam-Al Jufrah area during a complex hydrogeological survey. Water from different aquifers can be differentiated by their isotope content. The results generally show ¹⁴C ages older than 12,000 years with increasing groundwater age going towards the east and southeast. The hydrogeological concept of a continuous flow from the Palaeozoic aquifer through the Chicla aquifer towards the Mediterranean Sea is confirmed by the ¹⁴C measurements. This means that the Socna aquifer is recharged from the Palaeozoic aquifer, and the Eocene aquifer from the Chicla aquifer. The stable isotope content sorts the waters of the investigated aquifers into two groups. The relatively high ²H- and ¹⁸O-contents of the Upper Cretaceous aquifers and the Chicla aquifer indicate a possible recharge during pluvial times from Jebel Nefusa. Low ²H- and ¹⁸0-contents of the Palaeozoic, Chicla, Eocene and, in particular, the Socna aquifer, confirm the recharge of the Socna aquifer from deeper aquifers and show that the Palaeozoic and Chicla aquifers belong to an interconnected underground system. (author)