Journal of Palaeogeography（Chinese Edition）-Channel: PAST AND PRESENT GEOGRAPHY ENVIRONMENT AND HUMAN CIVILIZATION

Environmental evolution and hominin behavior adaptation of Shanghu Paleolithic site,Jiangxi Province

2025-01-20 09:48:11.007

Understanding the depositional process and paleoenvironment of the archaeological site is crucial for comprehending ancient human technology behavior. The Shanghu site,an open-air Paleolithic site,was newly discovered in southern China. Abundant stone artifacts,characterized by miniaturization,were unearthed from the homogeneous red soil B layer,dated to approximately 26 000 years ago. Integrated field investigation,micromorphology,magnetic susceptibility,grain size,geochemistry and archaeological taphonomy were comprehensively conducted. Our findings reveal that the homogeneous red soil B layer was primarily influenced by low-energy slope water processes,which allowed for the preservation of relatively intact records of ancient human technological behavior. The Shanghu site was frequently occupied by ancient humans during the MIS2 period. This may be related to the fact that ancient humans in North China with small flake tool industry were unable to withstand the extremely cold-dry climate,and were compelled to migrate southward,eventually arriving in the middle and lower reaches of the Yangtze River where the climate was relatively dry and cool. Moreover,ancient humans adopted a logistical mobility strategy to cope with the risks of uneven distribution and reduced predictability of resources caused by the extreme climate.

Palaeoenvironmental background of Qiaotou Site in Chushandian reservoir area in the upper reaches of Huai River

2025-01-20 09:48:11.007

The Huai River is a river of great significance to the Chinese civilization. However,compared with researches in the Yellow River and Yangtze River basins,archaeological and palaeoenvironmental research in the Huai River Basin has been relatively lagging behind. Qiaotou Site is an important site of the Shijiahe culture in the upper reaches of Huai River. This paper studied the environmental changes before and after the formation of Qiaotou Site,as well as the relationship between the palaeoflood events and the survival of the site,through stratigraphic investigations and testing and analyses of indoor samples from the Qiaotou site area and its adjacent areas. The results showed that at least 2 km around Qiaotou Site was covered by lakes or marshes during 8.1~4.6 ka BP(9.1~5.4 cal. ka BP)before the formation of Qiaotou Site. After about 4.6 ka BP(5.4 cal. ka BP),the ancestors were attracted to live in this region by its excellent natural environment,such as the warm and humid climate,highland terrain,and water source—Muzi River adjacent to the site's,etc. Unfortunately,this region became unsuitable for human habitation in the millennium after the Shijiahe culture due to the frequent environmental changes such as climatic anomalies(4.0 ka BP),floods caused by climatic fluctuations(3.5 ka BP,i.e. 3.9 cal. ka BP),and the diversion of the Huai River(3.2 ka BP,i.e. 3.6 cal. ka BP). After 3 ka BP(3.3 cal. ka BP),the ancestors settled here again as the temperatures in the Qiaotou site area gradually increased and became warmer. However,the ancestors had to leave this area again after 2.5 ka BP(1.8 cal. ka BP),as the highly fluctuating climate and frequent floods threatened the human survival.

Environment evolution since the Holocene revealed by lacustrine sediments of Meiyan borehole in Taihu Lake,eastern China

LUO Wenjing, WU Li, MA Chunmei, ZHU Cheng, LU Shuguang — 2025-01-20 09:48:11.007

In this study,we investigate the Meiyan borehole located on the southeastern shore of Taihu Lake. Based on a reliable chronological sequence established by AMS¹⁴C dating,we use elemental geochemistry,including Rb and Sr concentrations and the Rb/Sr ratio,to reconstruct Holocene climate changes. Additionally,foraminifera analysis is employed to explore whether the Taihu Lake region was affected by transgressions. The results show that from 11.0-9.1 cal. ka BP,the climate of Taihu Lake Basin gradually changed from humid to dry;from 9.1-6.1 cal. ka BP,the general climate was generally humid,with the wettest period occurring during 8.8-7.1 cal. ka BP;from 6.1~2.0 cal. ka BP,the climate was generally dry with the lowest precipitation;from 2.0-0 cal. ka BP,the precipitation gradually increased and the climate was humid. During the whole Holocene period,the eastern area of Taihu Lake was unlikely to have been influenced by transgressions. Regional comparisons show that the Rb/Sr record in Taihu Lake are consistent with environmental proxies record in neighboring regions during the middle and late Holocene,which is characterized by gradually drying climate in the Middle Holocene and wet climate since 2.0 cal. ka BP. To further explore the climate dynamics,we compared the environmental proxy index with the 30° solar radiation in the northern hemisphere,ENSO frequency records and Holocene mean sea level records. We found that the climate of Taihu Lake Basin was controlled by the solar radiation and ENSO changes,with distinct phases of dominance and coupling between the two factors. Solar radiation affected the early and middle Holocene climate of Taihu Lake Basin through direct and indirect effects. Since 2.0 cal. ka BP,the climate has exhibited an El Niño-like state,with an intensified ENSO frequency balancing the effects of weakened solar radiation on precipitation in the monsoon region. As a result,ENSO frequency became the main controlling factor of the climate in the Taihu Lake Basin. The results will provide a reliable basis for understanding the relationship between monsoon and climate change in the lower reaches of the Yangtze River since the Holocene.

Uncertainty in reconstructing palaeogeographic boundary conditions in palaeoclimate modelling

ZHU Guangkun, ZHANG Yurui, QIN Guojin — 2025-01-20 09:48:11.007

As climate models are increasingly applied in palaeoclimate studies,the reconstruction of more accurate palaeogeographic boundary conditions has become a key factor in understanding deep-time climate change mechanisms. However,the uncertainty in this reconstruction process has received little attention. This study investigates this uncertainty and its impact on model simulation results,based on reconstruction methods and data selection for palaeo-sea-land distribution,palaeo-sea depth,and palaeo-topography. Our results show that: (1)When reconstructing sea-land distribution,choice of reference plate movement models significantly affects the latitude and longitude of the reconstructed plates,so this demonstrate that model selection should align with research goals. Moreover,accurate correction of sea-land distribution requires multiple palaeoenvironmental proxy indicators,considering their uncertainties. (2)The reconstruction of palaeo-sea depth is more uncertain due to its complex process. Updating the oceanic crust age,choosing a depth-crust age relationship model,selecting a sediment model,and adjusting depth in key areas can all lead to different ocean depth reconstruction results. In particular,special attention should be paid to critical areas like sea channels,the state of this areas directly affect ocean current patterns and temperature-salinity changes in some ocean basins. (3)The uncertainty of palaeo-topography reconstruction is mainly influenced by factors such as the richness and uncertainty of height proxy indicators. (4)Correcting sea-land distribution and reconstructing sea depth leads to differences in basin size and seabed topography. These differences directly impact ocean currents and air-sea exchanges. In summary,uncertainty arises at every step of the palaeogeographic boundary conditions reconstruction process,which will greatly affect the accuracy of model output. To mitigate this,optimizing reconstructions by adding more proxy indicators will be required. Additionally,using multi-model results and geological records for verification is critical when analyzing climate model output,involving palaeogeographic boundary uncertainty.