Pollen-recorded bioclimatic variations of the last ∼22,600 years retrieved from Achit Nuur core in the western Mongolian Plateau

This research focuses on the reconstructions of vegetation variations and the associated climate changes over the past ∼22,600 years based on pollen data of 91 samples obtained from Achit Nuur in the western part of the Mongolian Plateau. The vegetation in the Achit Nuur area was forests in higher elevations and steppes in lower elevations from ∼22,600 to ∼13,200 cal BP. The subsequent period from ∼13200 to ∼6400 cal BP was characterized by steppes in higher elevations and deserts in lower elevations, followed by taiga expansion in high elevations in the following period from ∼6400 to ∼1600 cal BP. The last ∼1600 years were characterized by high herb percentages. Pollen-based reconstruction of the temperature showed that the Achit area experienced cold conditions between ∼22,600 and ∼13,200 cal BP and mild conditions from ∼13,200–∼6400 cal BP with the past ∼5000 years being relatively warm. The reconstructed precipitation suggests two wet periods: (1) from ∼22,600 to ∼13,200 cal BP and (2) from ∼6400 to ∼1600 cal BP. The two intervening dry periods are (1) from ∼13,200–∼6400 cal BP and (2) from ∼1600 to 0 cal BP.