Astronomical Forcing on Loess Deposition in the Junggar Basin Since the Late Pliocene

Deciphering dust outbreak frequency in inland Asia during the late Cenozoic is important for predicting future hydroclimate in the arid parts of China. Here, we present an eolian sedimentary sequence in the southern Junggar Basin over the past 3.5 Ma, Northwestern China. Our data provide a minimum age of 3.5 Ma for the Gurbantunggut Desert. Rb/Sr ratios exhibit prominent 405 Kyr eccentricity cycles throughout our record with weak expression 41 Kyr cycles. We interpret this cyclicity as resulting from a strong impact of the global carbon cycle on western China hydroclimate. By contrast, gamma-ray intensity data displays significant 100- and 41-Kyr cycles after 2.8 Ma, suggesting important variations of the input of westerly derived dust. Our results demonstrate that Westerly derived moisture supply and dust input into inland Asia respond differently to orbital forcing; they suggest that moisture supply and dust transport by the Westerlies are controlled by different drivers since 3.5 Ma.

Automated summary

Deciphering the frequency of dust outbreaks in inland Asia during the late Cenozoic is crucial for predicting future hydroclimate in arid regions of China. This study presents a sedimentary sequence from the southern Junggar Basin in Northwestern China, dating back to the past 3.5 million years. The findings suggest that the Westerly derived moisture supply and dust input into inland Asia have different responses to orbital forcing since 3.5 million years ago. This highlights the importance of considering different drivers for moisture supply and dust transport in understanding hydroclimate changes.