## 1 Introduction  
East Asia is located in the western Pacific Ocean region, in the Eurasian hinterland. Affected by a strong sea-land thermal difference and the high-altitude Tibetan Plateau (TP), it provides a heat and water vapor transmission channel between Eurasia and the Northwest Pacific. It is an important part of the global climate system [1]. Any changes in the East Asian Monsoon (EAM) can affect the economic and living conditions of two-thirds of the world's population. Understanding how the EAM climate can change is therefore of huge scientific and societal importance [2]. The modern monsoon system is characterized by strong seasonal variability. During the winter, when a principally northwesterly wind blows, the EAM region is very cold and dry; in the summer, the region is warm and humid [3]. The hot airmass transmitted to the EAM region by the southesterly wind that blows from the Pacific Ocean dominates the summer months, when precipitation (P) levels are at their highest [4]. The EAM circulation has undergone many periodic changes since the Last Glacial Period (LGP). The alternation of the East Asian Summer Monsoon (EASM) and the East Asian Winter Monsoon (EAWM) affects temperatures (T) and P throughout the region [5; 6; 7]. Glaciers are highly sensitive to regional environmental changes. As such, they can accurately reflect long-term environmental change. Glacial proxies therefore have an irreplaceable role in delineating any changes in the regional climate and environment [8; 9]. The potential correlation between glacial development (advance/stasis/retreat) and environmental change offers a new theoretical perspective, i.e., that Late Quaternary (150 ka) glaciers in the middle and low latitudes of East Asia may have resulted from the coupling of a particular region's climate and geomorphology [10; 11; 12]. It has been suggested that the Late Quaternary glacial period in the EAM region started late, in the Early LGP at the earliest [13]. [PERSON] [14] concluded that the coastal areas of East Asia approached, or reached, the equilibrium line altitude (ELA) for the development of glacial ice during the LGP, as a result of strong tectonic movement. On the other hand, other studies have maintained that, in response to the EAM climate, mountain glacier development (advance/stasis/retreat) depended more on P and T and exhibited some characteristics typical of marine glaciers [15; 16; 17]. Marine glaciers are heavily dependent on the supply of P and T, especially during the winter months, when falls of rain or snow can aid the development of glacial ice [18; 19; 20; 21]. [PERSON] [22] pointed out that the ELA in the EAM region during the Last Glacial Maximum (LGM) was more than 10 degrees of latitude further south than for areas of the same altitude in central Asia; the mountain paleo-ELA (\(\Delta\)ELA) for mountains in the EAM region was \(>\)500 m lower. [PERSON] et al. [23] stated that the ELA in the EAM region is now higher than the mountains in that region, explaining why modern glaciers cannot develop. [PERSON] et al. [24] proposed differences in glacial development patterns between the East Asian Intracontinental and the EAM regions. After all, scholars have recognized the climate and environmental particularity of glacier development in the study area; the key point of the study is the earliest time and the driving factors of glacier development. There remains a paucity of research into the evolutionary features of the glacial stages in the mountain ranges of this particular climatic region. Furthermore, the specific relationship between different glacial stages and the monsoon environment has yet to be fully explored. This study has attempted to clarify the developmental characteristics of different glacial stages in the mountains of the EAM region and discover the principal reasons for the region's deglaciation.