Spatiotemporal variations and implications of luminescence sensitivity of quartz grains on the Chinese Loess Plateau since the last interglaciation

Abstract

Although luminescence sensitivity of quartz grains of desert sands has been used in discriminating provenance, it still remains unclear about its spatiotemporal variations and climatic implications. In this paper, the luminescence sensitivity of quartz grains from the northern margin of the Chinese Loess Plateau (CLP) was studied using single-aliquot optically stimulated luminescence (OSL) and “pseudo” single-grain OSL measurements. Our results indicate that the OSL sensitivities have lower values in sand/loess beds and higher values in paleosols. We suggest that the variations in OSL sensitivity of quartz grains with depth on the CLP are mainly influenced by the origin of the quartz grains as they are related to the loess-sized material production processes and the migration of desert regions. More quartz grains of glacial origin with lower luminescence sensitivity, together with the reduced durations of irradiation and exposure cycles induced by shorter transport distance due to desert expansion, account for the lower luminescence sensitivity of glacial periods. Moreover, both the mountain processes and the retreat–advance of deserts are ultimately related to climatic changes, therefore, the orbital scale variations of luminescence sensitivity are controlled by glacial–interglacial oscillations on the CLP.

Luminescence Sensitivity of Quartz From Rocks Under in situ Chemical Weathering Conditions

“…However, we can conclude that 110 °C TL sensitivity is more responsive to chemical weathering under the same conditions. This can also be noticed in previous work (Lü et al, 2014;Lü and Sun, 2017;Li and Zhou, 2020;Lü et al, 2020), where quartz in Paleosol or Pedocomplex has a higher QLS compared to loess, and the luminescence sensitivity of TL is several times higher than that of OSL. The difference, however, is that our QLS values are in the tens to hundreds of percent of the values in the above literature.…”

“…Different deserts of northern China exhibit discrepancies in QLS and a decreasing trend from east to west, with one exception of the Gurbantunggut Desert (Li et al, 2007;Zheng et al, 2009;Lü and Sun, 2017). Vertical variations in QLS measured from loesspaleosol sequences show a good correlation with other proxies, such as median grain size and magnetic susceptibility, which may reflect climate change or sediment transport dynamic changes (Lü et al, 2014;Qiu and Zhou, 2015;Li and Zhou, 2020;Lü et al, 2020). With an increasing distance of fluvial sediment transportation, sensitizing QLS is observed by Pietsch et al (2008) and Sawakuchi et al (2011a), but this growing trend does not always persist.…”

Variation of luminescence sensitivity of quartz grains from loess in eastern Tibetan Plateau and its provenance significance

“…The highest luminescence sensitivity of the WCH loess, without overlap with other regions, shows a different source region with less contribution of dust materials produced by glacial activity. The luminescence sensitivity of the ZQ section is obviously different from that of other loess profiles on the Tibetan Plateau, but it is close to the luminescence sensitivity values of the CLP profiles (Zhang, 2018;Lü et al, 2021;Li and Yang, 2022). This may indicate that the ZQ loess has a similar dust source to the CLP loess.…”

“…The highest sensitivity value of approximately 9,310 counts/Gy/mg appears in the WCH profile in the L1 layer on the ETP. The Shimao section from the northern CLP has an OSL sensitivity for quartz grains (38-63 μm) of less than 100 counts/Gy/mg during the L1 loess accumulation period (Lü et al, 2021), while the OSL sensitivities of the L1 loess layer at Jingyuan (the particle size fraction used is 45-63 μm) and Luochuan (25-64 μm) are approximately 950 counts/Gy/mg and 1,230 counts/Gy/mg, respectively (Zhang, 2018). An OSL sensitivity value of approximately 333 counts/Gy/mg (38-64 μm) for the L1 was measured in the Xifeng profile (Li and Yang, 2022).…”

“…Comparison of optically stimulated luminescence (OSL) sensitivity observed for the L1 layer in the Chinese Loess Plateau and eastern Tibetan Plateau (JY, Jingyuan (Zhang, 2018), XF, Xifeng (Li and Yang, 2022); LC, Luochuan (Zhang, 2018), SM, Shimao (Lü et al, 2021); XS, Xinshi; MC, Machang; XJ, Xiaojing, WCH, Wenchuan, and ZQ, Zhouqu).…”