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Bangladesh is one of the most densely populated countries in the world. There are 57 trans‐frontier rivers in the country, the widest being the Brahmaputra River. The river's channels have frequently changed course, but the relationship between such river migrations and human settlement patterns has remained unstudied. In this paper, optically stimulated luminescence and radiocarbon dating techniques were applied to sedimentary and organic materials in the oldest urban center (Wari‐Bateshwar) in Bangladesh. The results showed that the landscape around the urban center was dominated by floodplain and peatland facies between 7.9–7.6 and 4.7–1.6 ka, respectively. Humans occupied this area at ~3.2 ka, and manufactured delicate semi‐precious gemstone beads between ~2.4 and 1.8 ka. The urban center might be the same as an important city of the Gangaridai described in historical records. Due to fluvial migration at ~1.8 ka, the area surrounding the urban center was covered by fluvial sand. Humans might have been forced to abandon the urban center, leading to the bead processing technology in Bangladesh being lost forever. [ABSTRACT FROM AUTHOR]

Vast palaeolakes once occupied the Qinghai‐Tibetan Plateau (TP). Analyses of the sedimentary records of these lakes could potentially provide an extensive dating archive. Many previously constructed age‐depth models simulating lacustrine cores have been principally based on radiocarbon (14C) dating. However, such dating could have been hampered by the so‐called ‘lake reservoir effect’ (LRE) and the reworking of lakebed sediments, resulting in inaccurate 14C age‐depth models and limiting interpretations of existing lacustrine palaeoclimatic records. Lake Linggo Co is located on the central TP, in one of the coldest and most arid regions of Tibet. We dated a 9.87‐m‐long lacustrine core extracted from the lakebed at a water depth of ~60 m using a combination of 210Pb, 14C and optically stimulated luminescence (OSL) techniques. Some 14C ages showed significant age reversals; all the 14C ages were much older than the 210Pb and OSL ages for the same depths. This could possibly be attributed to the presence of old, inherited carbon, causing the inherited 14C age to appear unstable during the deposition period. The 210Pb and OSL ages were roughly concordant, and were also consistent with the stratigraphical succession. We therefore suggest that 14C dating may, on its own, be inadequate for accurate dating of lacustrine sediment sites on the TP, and that the OSL method should also be applied in order to evaluate the reliability of any 14C ages. With this approach, we constructed an age‐depth model, revealing sedimentation rates of 1.7, 0.8, 6.8 and 0.6 mm a−1 between 0–1.9, 1.9–4.2, 4.2–4.4 and 4.4–9.4 ka, respectively. [ABSTRACT FROM AUTHOR]

Human activity and adaptation to the environmental changes on the Tibetan Plateau are under debate. Lhasa is the political and economic center of the Tibetan Autonomous Region, and was founded in 633 CE. The potential influence of changes in the landscape on the city's development remains unclear. In this paper, Optically Stimulated Luminescence and radiocarbon dating techniques were applied to determine the ages at which landforms have changed since the Last Glacial Maximum. Combining these results with archaeological evidence taken from two sites (Changguogougou and Qugong) in the Lhasa area, the relation between river migration and human adaptation was discussed. The results showed that the two terraces (T1 and T2) of the Lhasa River are fill and fill-cut terraces, and that these were formed after ∼0.9 ka and 0.08 cal ka BP, respectively. Land below an altitude of ∼3650 m above sea level was lower than the contemporary river level before ∼0.9 ka. With the down cutting of the Lhasa River, more land became available for habitation, and the flood risk to the city was also reduced. The sediments of the lower land around the Changguogou area appear to be composed of fluvial-lacustrine facies during the Last Glacial Maximum to Late Glacial period. Humans occupied the Changguogou area between ∼3.255 and 3.059 cal ka BP when there was weaker aeolian activity, and abandoned this area when aeolian activity increased. [ABSTRACT FROM AUTHOR]

The Yangtze River is the longest watercourse in China, where it flows through the most densely populated and richest regions. The upper course of the River (Jinsha River) has been recurrently blocked over the course of time. The dam-outburst flood process has exerted a significant impact on the river's drainage area. However, the frequency of such events along the course of the Yangtze River remains poorly investigated. In this study, damming chain sediments were identified in the First Bend area of the Yangtze River, and were dated using optically stimulated luminescence (OSL) and 14C techniques. The obtained ages would suggest that the river was dammed by a debris flow during the ~20–7 ka period, with a resulting paleolake covering an area of 40.79 km2 and having a water volume of 0.63 km3. Two outburst megafloods occurred at ~18–20 and ~ 6.0 ka, respectively. The river was re-dammed again during 1.5–0.4 ka, with a lake coverage of 28.20 km2 and water volume of 0.28 km3. The dammed lake may have been gradually breached after ~0.4 ka. The damming events were caused by debris flows triggered by glacial advances on Yulong Mountain. • Fully investigated the paleo- damming chain sediments in the First Bend area of the Yangtze River. • OSL and 14C ages suggest that the river were dammed twice by debris flows during the ~20–7 and 1.5–0.4 ka period, and two outburst megafloods occurred at ~18–20 and ~ 6.0 ka, respectively. • The damming events were caused by debris flows triggered by glacial advances on Yulong Mountain. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau and Indian Plain exhibit the largest altitudinal difference between two geographically contiguous areas on Earth, but the eastern margin of the Plateau has not experienced headward erosion of the Yarlung Zangbo River (YZR) since ~2.5 Ma. In the past, some scientists have argued that moraine dams on Mount Namcha Barwa (in the Eastern Himalayan syntaxis) frequently blocked the YZR, thus keeping the Plateau's margin intact at this point. In this study, three sets of moraines were identified in the Pai Valley alongside Namcha Barwa, and were dated using optically stimulated luminescence (OSL) and 10Be exposure dating. The resultant ages would suggest that three glaciations occurred at ~22.2, 4.7 and 1.3 ka, respectively. Comparison of OSL and 10Be ages for glacial advances with local paleoclimatic proxies would suggest that temperature was the dominant factor controlling glacial change. Because of the paleoglacial advance frequency, coupling with rapid fluvial incision, moraine dams were cut through by the YZR. Thus, any moraine dams that lost their efficacy in impacting upon knickpoint migration. Instead, similarities between rock uplift and fluvial incision, rather than moraine dams, might have been the main control impeding headward erosion of the YZR, thereby keeping this part of the eastern Tibetan Plateau margin intact. • Glacial-fluvial landscape development explored in the Eastern Himalayan syntaxis were mapped and dated in the Pai Valley • OSL/TCN ages cluster to ~22.2, 4.7, 1.3 ka, associated with climate-glacial advances • Glacier extent-timings and knickpoints in relation to river gorge damming explored • Uplift-fluvial incision balance controls eastern Tibetan Plateau margin stability [ABSTRACT FROM AUTHOR]