## 5 Discussion  
### Analysis of the Reliability of the Glacial Chronology of the EAM Region  
Moraines are direct products of glacial events. The accumulation age of a moraine reflects the time of the glacial period/stage. In principle, a glacial period/stage cannot occur during a period of climatic warming, but only during a period of cooling. Using the dated ages of moraines deposited by glaciers during different periods/stages, an overall glacial chronology can be established [80]. This research compiled a glacial chronology of the EAM region. However, as this study synthesized moraine chronologies constructed using different dating techniques, chronological differences in the dated ages of the same moraine were inevitable [81; 82; 83]. For example, when analyzing the stratigraphic sedimentary sequence, OSL samples are collected from buried lateral moraine sediments, whereas \({}^{10}\)Be exposure samples are extracted from the boulders on top of the lateral moraine dams. According to the relative ages of these sediments, the OSL burial ages should be greater than the \({}^{10}\)Be exposure ages. Secondly, integral to each dating mechanism, the \({}^{10}\)Be exposure age is calculated according to the zero erosion rate, while the OSL is calculated according to the amount of cumulative exposure experienced prior to burial: this would also imply that the OSL burial age should be greater than the \({}^{10}\)Be exposure age [36]. Overall, the age of buried moraine sediments > the age of moraine exposure samples. Under the normal conditions, optically stimulated luminescence (OSL), thermoluminescence (TL), electron spin resonance (ESR) and U-series (U) dating techniques may be older than cosmogenic nuclides (\({}^{10}\)Be/CRN) techniques. In addition, as glacial deposits often lack organic matter, carbon-14 (\({}^{14}\)C) cannot effectively indicate age, age change may be large; potassium-argon (K-Ar) dating technique often samples volcanic sediments from the lower layer of glacial  
Figure 3: Comparison of mountains glacial period between EAM region and adjacent areas. Data reference from [9; 13; 78]. Benthic \(\delta^{18}\)O curve reference from [79], numbers represent the marine isotope stages. I: Holocene; II: Last Glacial Period; III: Last Interglacial; IV: Penultimate Glaciation; V: Penultimate Interglacial; VI: Zhonglianggan Glaciation; VII: Great Interglacial; VIII: Wangkun Glaciation. AIA: Asia Inland area; TP: Tibet Plateau; HD: Hengduan Mountains, see Figure 1 for geographical location. sediments, the age may also be older. The difference of the glaciers' age cannot be avoided by different dating techniques. The effective validation of ages extracted using different dating techniques is therefore key; any chronological glacial data should be compared with the glacial history of the surrounding mountains, and chronological glacial data should be consistent with regional environmental characteristics. The oldest extant glacial features mark the maximum local glacial extent. In other words, earlier glacial relics may have been overridden or eroded. In such cases, how can we exclude the possibility that earlier glacial advances occurred, and that the onset of any glaciation was synchronous across the study area? Mountain altitudes are a critical factor in determining the extent of any glaciation. In western China (Figure 3), which is latitudinally adjacent to the EAM region, the oldest glaciation has been identified and named the Kunlun glacial period, which occurred during MIS 16\(-\)18 (820\(-\)620 ka) [84]. Scholars have also proposed the existence of an earlier, 1600-1700 kunlun glacial period (MIS 28\(-\)21) on the TP, otherwise known as the Hishabanna glacial period [85]. The Hengduan Mountains (HD MTs) are located on the southeastern edge of the TP.