## 3 Methods and Datasets
### Spatiotemporal Distribution of Mountain Glacier Records in the EAM Region  
#### 3.2.1 Eastern China Mountains  
* Helan Mountains  
The Helan Mountains are located in northern China. There are clear traces of glaciation >2800 m above sea level (asl); two-stage cirques and geomorphic features typical of glaciation are distributed on both sides of the ridge. Using field investigations and comparisons between different OSL dating datasets, we confirmed that there were four glacial advances in the Helan Mountains, i.e., during the middle LGP (MIS 3b; \(43.2\pm 4.0\) ka), the LGM (19.3 \(\pm\) 1.4 ka), the Younger Dryas event (YD) (12.0 \(\pm\) 1.1 ka), and the Holocene glacial period (MIS 1; 3.4 \(\pm\) 0.3 ka and 1.7 \(\pm\) 0.1 ka) [33]. At present, there is no term for any corresponding glaciation sequences.
* Mount Taibai  
Mount Taibai is the highest peak in eastern China. It is located in the Qinling Range, which is considered to represent the dividing line between the northern and southern China. Scientists have proposed highly divergent onset times and geomorphic distributions for Mount Taibai's Late Quaternary glaciers; there are also differing views on the subdivision of the Late Quaternary glacial period, whether that be into multiple glacial stages, four glacial stages, two glacial stages, or even two substages of one glacial period [55,56]. [PERSON] [34] dated the inner moraine below the Sanguagchi Tarn in the upper reaches of the Heihe Valley to 19 \(\pm\) 2.1 ka used ESR dating, corresponding to the Eryehai glacial stage of the LGM. [PERSON] et al. [37], [PERSON] [35] and [PERSON] et al. [36] used ESR, \({}^{10}\)Be, and OSL dating techniques, respectively, to determine the date of the moraines on Mount Taibai, and variously came up with dates of 22.1 \(\pm\) 1.7-15.07 \(\pm\) 0.92 Ka, corresponding to the Dayehai glacial stage of the LGM-LGP; dates of 7.6 \(\pm\) 0.27 ka, 3.51 \(\pm\) 0.16 ka and 2.74 \(\pm\) 0.11 ka corresponded to the Baxiantai glacial stage of the Holocene glacial period (MIS 1), when the glacial retreat that had occurred after the LGM was temporarily reversed. The geomorphic properties of the three sets of lateral moraines in the Eryehai valley indicate that they are likely to be the products of different stages of the LGP. Indeed, it is possible that there may have been an earlier glacial stage (i.e., the Yuhuang stage, MIS 3b).
* Changbai Mountains  
Baiyun Peak on the Chinese side of Lake Tianchi in the Changbai Mountains is the highest peak in northeastern China. Late Quaternary glacial geomorphic features are clearly preserved above 2000 m asl in the Changbai Mountains, showing evidence of multiple glaciations. However, the history of these glacial stages and their specific subdivision has remained unclear, principally due to erosion and volcanic activity that has affected the accurate dating of moraines. In recent years, using the OSL dated ages of moraines around the Baiyun Peak stratovolcanic crater and combining these findings with the relationship between glacial development and volcanic activity, two glacial stages in the Changbai Mountains have been determined, i.e., the Heifengkou glacial stage at 20.0 \(\pm\) 2.1 ka during the LGM and the Qixiangzhan glacial stage at 11.3 \(\pm\) 1.2 ka during the YD [37]. Earlier glaciations remain to be further investigated.