ESR geochronology of the Minjiang River terraces at Wenchuan, eastern margin of Tibetan Plateau, China

Abstract

Abstract:The Minjiang River terrace along the Longmen Shan fault zone near Wenchuan, at the eastern margin of the Tibetan Plateau, China, provides archives for tectonic activity and quaternary climate change. However, previous studies were not able to provide ages older than 100 ka due to the limitations of dating material or/and methods applied to date the fluvial sediments. In this study, we used the ESR signal of the Ti-Li center in quartz to obtain the ages of four higher terraces (T3-T6). According to the results, the terraces T3 to T6 were formed at 64±19 ka, 101±15 ka, 153±33 ka, and 423±115 ka, respectively. Combined with previous studies, these results indicate that the formations of all terraces correspond to glacial/interglacial transition periods, such as, T1-T5 being correlated to MIS2/1, MIS4/3, MIS5d/5c, and MIS6/5e respectively, while T6 probably to MIS12/11. According to these data, it is found that the average incision rate was significantly higher over the last 150 ka than that previous 100 ka (250 to 150 ka). As both tectonics and climate have affected the formation of these terraces, in addition to the overall uplifting of Tibetan Plateau, the regional uplift due to isostasy would be an additional tectonic factor in the formation of river terraces in the eastern margin of Tibetan plateau.

Effects of grain size on quartz ESR dating of Ti–Li center in fluvial and lacustrine sediments

“…Voinchet et al, 2007;Tissoux et al, 2008;Liu et al, 2010Liu et al, , 2013aLiu et al, , 2013bLiu et al, , 2014, the 100e200 mm fraction has been used to quartz ESR dating of Quaternary sediment sample. In this study, the 50e100 mm, 100e150 mm and 150e200 mm fractions yield the same results in the error range.…”

“…Voinchet et al, 2007Voinchet et al, , 2010Tissoux et al, 2008;Liu et al, 2010Liu et al, , 2013aLiu et al, , 2013bLiu et al, , 2014. In such sediment, the size of the grain varies from few micron meter to few centimeters, and the sensitivities of both ESR and OSL signals of the quartz showed strong grain size depended effects (Buhay et al, 1988;Pietsch et al, 2008;Fan et al, 2010).…”

Paramagnetic lattice defects in quartz for applications to ESR dating

“…The practical application using TieLi and TieH centers for dating of sediment was made by Tissoux et al (2007). ESR dating with the TieLi center signal was shown to work for the sediments in river terraces in China in the age range of 60e400 ka (Liu et al, 2013). Extensive efforts were devoted by and by Beerten and Stesmans (2007) for dating of single grain sedimentary quartz by observing the Ti center with a Q-band ESR spectrometer.…”

Optical Dating of Quartz Grains From the Minjiang Fluvial Terraces in the Sonpan Area on the Eastern Margin of the Tibetan Plateau

“…Tectonic activities like uplift could be recorded by a flight of fluvial strath terraces on river banks (Cunha et al, 2008;Gong et al, 2014;Fu et al, 2016), especially in the Tibetan Plateau and nearby regions (e.g., Lavé and Avouac, 2001;Vance et al, 2003). The Minjiang River situated at the eastern margin of the Tibetan Plateau (Figure 1) is the main tributary of the Yangtze River and has been widely investigated to understand the relationship between river erosion and tectonic movements (Figure 1; Tang et al, 1991;Chen et al, 1994;Zhao et al, 1994;Kirby et al, 2000;Zhou et al, 2000;Yang et al, 2003;Li et al, 2005;Ma et al, 2005;Gao and Li, 2006;Wu et al, 2009;Liu et al, 2013). On the other hand, fluvial incisions along the banks of the Minjiang River and its tributary have also induced a number of large rockslides (Kirby et al, 2002;Wang et al, 2011;Wang et al, 2012;Zhao et al, 2019;Wu et al, 2020).…”

“…In the previous studies, the formation ages of the Minjiang River terraces were determined using various dating techniques including radiocarbon (Kirby et al, 2000), thermoluminescence (TL) (Tang, et al, 1991;Chen et al, 1994;Zhao et al, 1994;Zhou et al, 2000;Li et al, 2005;Ma et al, 2005;Gao and Li, 2006), infrared stimulated luminescence (IRSL, Kirby et al, 2000) and electron-spin resonance (ESR, Yang et al, 2003;Liu et al, 2013). However, the reliability of some of the ages obtained using these techniques requires further assessment.…”