Abstract:

Northeast China is of great importance in the development and diffusion of microblade technology. Reconstructing the vegetation ecology of Northeast China during the emergence of microblade technology is crucial for understanding the origins of microblade technology and ancient human beings’ adaptations to the environment.
This study focuses on the sedimentary profile of the Xishantou site. The site is located in Xishantou Village, Xingshan Township, Longjiang County, Heilongjiang Province, on the secondary terrace of the left bank of Chaor River. Excavations at the site uncovered fire-using features, lithic products and animal fossils. The lithics are located below a loess-type subclay layer and above a yellow fine silt and gravel layer in the Songnen Plain, and its stratigraphy belongs to Guxiangtun Formation of the Late Pleistocene in northeastern China. The main types of lithics are cores, blades and implements. The dense distribution of lithics with a certain spatial regularity in the excavated area suggests that this may have been a lithic workshop site.
AMS ¹⁴C results show that the major cultural layers of microblade technology at the Xishantou site are dated to around 27.8 kaBP cal, which corresponds to the GI-3 interglacial section of the late Marine Oxygen Isotope Stage 3 (MIS 3). By using the pollen analysis method, an attempt is made to reconstruct vegetation types from the late MIS 3 through the early Last Glacial Maximum (LGM) at the site. A total of 24 samples were collected for pollen analysis from the Xishantou site profile, and 31 pollen types were identified, with an overwhelming majority of herb pollen.
The vegetation and climatic characteristics of the cultural layer where the microblade technology emerged are also analyzed in combination with climate proxies and principal component analysis. The pollen analysis results show that the ancient human living environment was mainly the meadow-steppe type dominated by Poaceae and Asteraceae, with a relatively temperate and moist climate. Pollen results from the overlying loess-type subclay of the cultural layer show that the climate gradually shifted to a relatively cooler and drier climate and the vegetation changed to a typical steppe dominated by Artemisia and Asteraceae, indicating that this stage may have entered the LGM. Changes in the abundance of fungal spores indicate the presence of herbivorous mammals around the site.
These findings offer valuable scientific insights into the environmental context of ancient human existence during the emergence of microblade technology, shedding light on the ecological mechanisms behind the transition from blade technology to microblade technology.

Key words: paleovegetation reconstruction, Late MIS 3, microblade technology, palynology, Xishantou site