Provenance variations of the Tengger Desert since 2.35 Ma and its linkage with the Northern Tibetan Plateau: Evidence from U-Pb age spectra of detrital zircons

Abstract

Knowledge of variations of the sedimentary sources of the proximal deserts of the Chinese Loess Plateau (CLP) is important for understanding eolian processes linking environmental changes within provenance areas and the areas of deposition downwind. In addition, it may shed light on the history of the uplift of the Tibetan Plateau. However, the long-term variations in provenance of the proximal deserts of the CLP are still unknown. The Tengger Desert (TD) is one of the proximal deserts upwind of the CLP. It is located in a depression (also a plateau) on the northeastern margin of the Northern Tibetan Plateau (NTP) and to the south of the Gobi Altay Mountains (GAMs). Here, we present U-Pb age spectra of detrital zircon grains from 11 sand layers from core BJ14 which was drilled in the northwestern part of the TD. The ages of the sand layers range from 2.35 to 0.11 Ma. The results indicate that: (1) The GAMs and NTP were two competing provenance areas of sands in the TD. (2) The dominant provenance area of clastic materials in the TD area was GAMs during 2.35–1.80 and 1.2–0.6 Ma, and the NTP at ∼1.56 Ma and during 0.36–0.11 Ma. The shift in the dominant provenance area in the TD from the GAMs to the NTP was controlled by the phased uplift of the Tibetan Plateau against the background of global cooling. (3) The relative increase of the sedimentary contribution from the NTP was generally synchronous with increases in the accumulation rate and the enlargement of eolian sand/dust deposits downwind, but the increase began at a late stage in the phased uplift of the Tibetan Plateau. These findings indicate that the phased rapid uplift of the NTP was a trigger which dominated the variations in the provenance of the proximal deserts of the CLP and beyond.