The magnitude and rate of spatial expansion of the East Asian summer monsoon (EASM) rain belt as the climate warms remains unclear. Existing assessments still lack the ecological records that are more sensitive to the EASM rainfall to quantify the spatial extension during the past warming scenarios. Here, the spatiotemporal extension of EASM intensity since the last glacial maximum (LGM) is reconstructed using six well-dated mollusk fossil sequences from Chinese loess sections located at the northern part of the EASM. The abundant occurrence of typical dominant mollusk species indicative of EASM intensity gradually delayed from southeast to northwest since the last deglacial warming. The estimated expansion rate of EASM intensity accelerated markedly during the ~12-9 ka (~50 km/ka), which corresponded with the early-Holocene rapid warming period, shifting northwestward ~150 km compared to present. This imply that northern fringe of EASM in northern China will become wetter as the climate warms.

The dataset was collected at the Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China. The mollusk fossils were picked and identified under a binocular microscope, and counted their abundance to produce a MS.

DATA-SPECIFIC INFORMATION FOR: [mollusk records]

1. Number of variables: 22

2. Number of cases/rows: 141

3. Specialized formats or other abbreviations used: 

The variable uses the abbreviation YX, WN, JX, JC, SZ, LX, HX called Yaoxian, Weinan, Jixian, Jingchuan, Shuozhou, Linxia, Huanxian sites, respectively. PER: Percentage.