Vegetation and climate of the Lop Nur area, China, during the past 7 million years

Lop Nur in Xinjiang, Northwest China, is located in the lowest part of the Tarim Basin at an altitude of 780?m and experiences an extremely dry climate with an annual precipitation of only 17?mm and a high evaporation rate of 2,728?mm. The pollen and spores from the Late Miocene strata of a borehole in Lop Nur were analyzed with a view to interpreting the paleoenvironmental evolution of Lop Nur. Main types of pollen such as Chenopodiaceae, Nitraria, Ephedra and Artemisia reflect an arid climate. By collating the palynological data in this area as recorded in other literature and by applying the method of Coexistence Analysis, we have obtained the paleoclimatic parameters from Late Miocene to Holocene in Lop Nur. These suggest that temperatures increased from the Late Miocene (10.2°C) to the Pliocene (13.4°C), decreased from Pliocene to Pleistocene (4.7°C), and were more stable from Holocene (12.1°C) until now (11.5°C). The precipitation was stable (about 900?mm) from Late Miocene to Early Pleistocene, then decreased markedly (to about 300?mm) in Middle and Late Pleistocene, and reached its lowest value (17.4?mm) in the Holocene. The changes in paleoclimate at Lop Nur provide new evidence for understanding the uplift of the Qinghai-Tibetan Plateau.