Determining the Age of Terrace Formation Using Luminescence Dating—A Case of the Yellow River Terraces in the Baode Area, China

Abstract

Dating fluvial terraces has long been a challenge for geologists and geomorphologists, because terrace straths and treads are not usually directly dated. In this study, the formation ages of the Yellow River terraces in the Baode area in China were determined by dating fluvial deposits overlying bedrock straths using optically stimulated luminescence (OSL) dating techniques. Seven terraces (from the lowest terrace T1 to the highest terrace T7) in the study area were recognized, and they are characterized by thick fluvial terrace deposits overlaid by loess sediments. Twenty-five samples from nine terrace sections were dated to about 2–200 ka. The OSL ages (120–190 ka) of the fluvial samples from higher terraces (T3–T6) seem to be reliable based on their luminescence properties and stratigraphic consistency, but the geomorphologic and stratigraphic evidence show that these ages should be underestimated, because they are generally similar to those of the samples from the lower terrace (T2). The formation ages of the terrace straths and treads for the T1 terrace were deduced to be about 44 ka and 36 ka, respectively, based on the deposition rates of the fluvial terrace deposits, and the T2 terrace has the same strath and tread formation age of about 135 ka. The incision rate was calculated to be about 0.35 mm/ka for the past 135 ka, and the uplift rate pattern suggests that the Ordos Plateau behaves as a rigid block. Based on our previous investigations on the Yellow River terraces and the results in this study, we consider that the formation ages of terrace straths and treads calculated using deposition rates of terrace fluvial sediments can overcome problems associated with age underestimation or overestimation of strath or fill terraces based on the single age of one fluvial terrace sample. The implication is that, for accurate dating of terrace formation, terrace sections should be systematically sampled and dated.

Absolute Dating of Past Seismic Events Using the OSL Technique on Fault Gouge Material—A Case Study of the Nojima Fault Zone, SW Japan

“…Nevertheless, the significant number of available statistical approaches for calculating and selecting the most representative D E value should be noted here (e.g., Galbraith et al, 1999; Lepper & McKeever, 2002; Olley et al, 1998), which are particularly useful for partially bleached or inhomogeneous samples. Several studies (e.g., Hanebuth et al, 2013; Kunz et al, 2013; Moska et al, 2019; Zhang et al, 2020) have applied many of the different statistical approaches for calculating D E values of fine quartz grains. For gouge material, partial bleaching may be expected and depicted on D E values distribution.…”

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

“…It is noted that the channel gravel layer at this site is very thick (up to 12.6 m). The vertical distance from the strath surface to the sampling point is about 9.3 m. The thick terrace deposits may lead to the difference in ages among the dated samples, the terrace tread and strath (Zhang et al, 2020). If the deposition of the gravels and overbank silts at this site were rapid, the ages of the terrace tread and strath are approximately equal to those (20.2 ± 1.3 and 29.0 ± 1.7 ka) of samples SP16-16 from the overbank silt layer and -17 from the gravel layer, respectively.…”

“…On the other hand, if the deposition rate is relatively slow, the age of the dated sample could not directly represent the strath age, which is defined as the end of an interval of strath formation (Bull, 1991;Bull, 2007). Alternatively, tread and strath ages can be obtained by calculating a deposition rate for these sediments using an age-depth model (Zhang et al, 2020). We assumed an average deposition rate for the fluvial sediments and no hiatus between the two sedimentary facies, a deposition rate of 0.4 ± 0.1 m/ka was calculated based on the relationship between the ages and depths of the two fluvial samples.…”

“…The former two could result in age overestimation, and the third in age underestimation. Additionally, loess deposits overlying fluvial sediments were sampled for TL dating (Chen et al, 1994;Kirby et al, 2000), the loesses may be much younger than the underlying fluvial sediments (Yan et al, 2018;Zhang et al, 2020). But their OSL ages can represent the minimum ages of terrace-tread formation.…”

Methods and Applications in Trapped Charge Dating

“…Finally, Zhang et al [12] discuss the problems of dating fluvial terraces in China. They show that one sample from each of the terraces is not sufficient.…”