Sedimentological characteristics of four palaeolakes in the Tsakhiurtyn Hundi Lakeland (Gobi Desert, Mongolia)

We describe the sedimentological properties of four palaeolake basins located in the Tsakhiurtyn Hundi Lakeland, situated at the southern edge of the Arts Bogd massif in the Gobi Desert, Mongolia. The palaeolakes – Talingaryn Shal, Chavgantsyn Shal, Zuun Khuree, and Luulityn Toirom – are part of the endorheic Shereegiin Gashuun Basin. In this study, we reconstruct the local palaeogeographic and palaeoclimatic conditions from the Pleistocene to the Holocene through integrated field surveys, sedimentological profiling, and optically stimulated luminescence (OSL) dating. The sedimentation patterns reflect alternating fluvial, lacustrine and aeolian conditions that correspond to climatic oscillations and hydrological changes. OSL dating indicates that lakes in the region began to form during MIS-6 (138.3 ± 7.5 ka), and markedly expanded during MIS-5, particularly between 104 and 72 ka. The Holocene record shows evidence of episodic aridification, with dry phases dated to approximately 10.6 and 8.6 ka. In the Late Holocene, wetter conditions returned, lasting about 3.6 ka. Pollen analysis yielded limited results but recovery of cladoceran (water flea) remains in Lake Zuun Khuree indicates likely seasonality of this water body. These findings underscore the interplay of tectonic subsidence and climate-driven processes in shaping lacustrine systems across southern Mongolia. There is evidence too of early human activity, with archaeological traces being documented near the lake basins studied.