<abstract xmlns="http://www.w3.org/1999/xhtml">

The Qaidam Basin preserves the largest Yardang field on Earth, and yardangs are intriguing landforms for studies of the paleo-environment and aeolian processes. Formation of yardangs involved both the initial lacustrine deposition and the subsequent wind-erosion processes. However, the timings of both processes in the Qaidam Basin are still controversial due to limited age data and unsuitable dating methodology. In this paper, we first compared two optical dating methods to determine the suitable one for the study area, then investigated the geomorphic processes based on the new ages. Two-step post-IR IRSL (pIRIR) and multi-elevated-temperature pIRIR (MET-pIRIR) methods of feldspar, were applied to date lacustrine sediments on the top parts of yardangs to decipher the transition time from depositional to an erosional environment. Comparisons of the two methods demonstrated that the influence from anomalous fading was very minimal thus negligible for MET-pIRIR method, as proved by the De plateau between MET-pIRIR250 and MET-pIRIR290; while the pIR50IR250 signals suffered from fading obviously, which was difficult to be corrected due to the high De close to saturation. Consequently, the chronology in this study was based on the MET-pIRIR250 method, potentially offering reliable ages of over 200 ka. Seven MET-pIRIR250 ages of 201–336 ka suggested that a mega-Qaidam Lake (>2714 m a.s.l. on Google Earth) maintained until Marine Isotopic Stage (MIS) 7. The absence of sediments since <italic>ca.</italic> 200 ka implied wind-erosion and yardang formation since MIS6. This transition from lacustrine to a wind-erosion environment was interpreted as a response to the glacial-interglacial scale climatic changes.
</abstract>

The Qaidam Basin preserves the largest Yardang field on Earth, and yardangs are intriguing landforms for studies of the paleo-environment and aeolian processes. Formation of yardangs involved both the initial lacustrine deposition and the subsequent wind-erosion processes. However, the timings of both processes in the Qaidam Basin are still controversial due to limited age data and unsuitable dating methodology. In this paper, we first compared two optical dating methods to determine the suitable one for the study area, then investigated the geomorphic processes based on the new ages. Two-step post-IR IRSL (pIRIR) and multi-elevated-temperature pIRIR (MET-pIRIR) methods of feldspar, were applied to date lacustrine sediments on the top parts of yardangs to decipher the transition time from depositional to an erosional environment. Comparisons of the two methods demonstrated that the influence from anomalous fading was very minimal thus negligible for MET-pIRIR method, as proved by the De plateau between MET-pIRIR250 and MET-pIRIR290; while the pIR50IR250 signals suffered from fading obviously, which was difficult to be corrected due to the high De close to saturation. Consequently, the chronology in this study was based on the MET-pIRIR250 method, potentially offering reliable ages of over 200 ka. Seven MET-pIRIR250 ages of 201–336 ka suggested that a mega-Qaidam Lake (>2714 m a.s.l. on Google Earth) maintained until Marine Isotopic Stage (MIS) 7. The absence of sediments since ca. 200 ka implied wind-erosion and yardang formation since MIS6. This transition from lacustrine to a wind-erosion environment was interpreted as a response to the glacial-interglacial scale climatic changes.

Post-IR Irsl Chronology of Paleo-Lacustrine Sediments from Yardangs in the Qaidam Basin, NE Tibetan Plateau

Luminescence Research Laboratory, Shandong Provincial Key Laboratory of Water and Soil Conservation & Environmental Protection

School of Resource and Environmental Sciences

Geochronometria

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The Qaidam Basin preserves the largest Yardang field on Earth, and yardangs are intriguing landforms for studies of the paleo-environment and aeolian...

Post-IR Irsl Chronology of Paleo-Lacustrine Sediments from Yardangs in the Qaidam Basin, NE Tibetan Plateau

Pubblicato online: 31 dic 2021

Pagine: 313 - 324

Ricevuto: 15 feb 2019

Accettato: 15 apr 2020

DOI: https://doi.org/10.2478/geochr-2020-0016

Parole chiave
wind-erosion of Yardang, feldspar luminescence dating, anomalous fading, glacial-interglacial scale environmental change, Qaidam Basin, Qarhan Salt Lake

© 2019 Zhaojing Ding et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Post-IR Irsl Chronology of Paleo-Lacustrine Sediments from Yardangs in the Qaidam Basin, NE Tibetan Plateau

Pubblicato online: 31 dic 2021

Pagine: 313 - 324

Ricevuto: 15 feb 2019

Accettato: 15 apr 2020

DOI: https://doi.org/10.2478/geochr-2020-0016

Parole chiavewind-erosion of Yardang, feldspar luminescence dating, anomalous fading, glacial-interglacial scale environmental change, Qaidam Basin, Qarhan Salt Lake

© 2019 Zhaojing Ding et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Parole chiave
wind-erosion of Yardang, feldspar luminescence dating, anomalous fading, glacial-interglacial scale environmental change, Qaidam Basin, Qarhan Salt Lake