Hebei loess section in the Anyemaqen Mountains, northeast Tibetan Plateau: a high‐resolution luminescence chronology

Abstract

The extensive aeolian deposits of the Tibetan Plateau (TP) represent important environmental archives, recording information about the past interplay between the Asian monsoon and Westerlies and the link between dust accumulation and Quaternary glaciations. In the northeast TP, mantles of sandy loess form a distinct belt lying between 3500 and 4500 m a.s.l. on the east-facing slopes of the Anyemaqen Mountains. However, there is little chronological information about the loess deposits in this region. This study provides a detailed chronology for loess formation in the region using luminescence dating. A total of 29 samples were collected from an 8-m-thick homogeneous loess section at Hebei (HB) in order to date sand-sized (63-90 lm) quartz and K-feldspar fractions using optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL and pIRIR) signals, respectively. The resulting quartz and feldspar ages are in good agreement over the last 40 ka; beyond this (i.e. D e >120 Gy), the quartz age is underestimated, and the pIRIR 170 feldspar ages are considered more reliable. The HB loess section records continuous environmental information from c. 50 to c. 30 ka, i.e. throughout Marine Isotope Stage (MIS) 3. Mass accumulation rates (MARs) varied considerably over this period with increased dust accumulation around c. 38 ka and afterc. 32 ka; in between, and at the beginning of MIS 3 (50-40 ka), the dust accumulation rate was 50% lower. Finally, the HB section also records a MIS 2 hiatus of c. 17 ka duration, probably resulting from deflation. This study implies that loess deposition on the TP is predominantly an interglacial/interstadial phenomenon and the TP may be deflating at the same time as the Chinese Loess Plateau is accumulating, at least during MIS 2.

Prehistoric human occupation and adaptation on the hinterland of the Tibetan Plateau in the Early Holocene

“…The OSL sample processing, preparation, and De measurement were carried at the luminescence dating laboratory of the Qinghai Normal University. For detailed descriptions of the dating sample collection and pretreatment, please refer to E et al (2018).…”

Climate Conditions on the Tibetan Plateau During the Last Glacial Maximum and Implications for the Survival of Paleolithic Foragers

“…Ice wedge casts widely developed across the northern TP in response to the sharp cooling (Pan and Chen, 1997;Madsen et al, 2008;Liu and Lai, 2013). Loess, which accumulated on the northeastern TP during and prior to the LGM, was largely eroded away by strong winds and expanded glaciers (Liu et al, 2017;E. et al, 2018).…”

“…Existing paleoenviornmental records indicate that lakes on the TP shrank during the LGM, with some large lakes becoming almost completely desiccated (Madsen et al, 2008;An et al, 2012;Yan and Wünnemann, 2014;Jin et al, 2015;Liu et al, 2015;Zhu et al, 2015). Loess was eroded by strong westerly winds and the advancement of glaciers during the LGM (Liu et al, 2017;E et al, 2018). Ice wedge casts indicative of permafrost developed widely across the northern TP, and vegetational communities were substantially degraded (Pan and Chen, 1997;Liu and Lai, 2013).…”

Rare earth elements in aeolian loess sediments from Menyuan Basin, northeastern Tibetan plateau: Implications for provenance

“…This material results from physicochemical and mechanical processes, such as erosion, transport, and deposition, which are driven to the sedimentary site by external inputs (e.g., wind force) from the provenance area (e.g., gobi and desert) (Muhs, 2013;Obreht et al, 2015;Li et al, 2020a;Li et al, 2020b). Hence, aeolian loess constitutes a unique terrestrial archive containing extensive environmental information on provenance, deposition, and air transport to reveal atmospheric circulation patterns and reconstruct paleoclimate shifts during the Quaternary (E et al, 2018;Sun et al, 2019;Li G et al, 2020;Miao et al, 2022).…”