Microblade technology and site structure of the Late Mesolithic hunter-gatherers in Donggi-Cona Lake Basin: new implications for human dispersals and interactions in the northeastern Tibetan Plateau during the Holocene

Changes in moisture conditions or precipitation in the SE Tibetan Plateau during the Holocene have been studied using various environmental archives and proxies. However, due to different interpretations of the proxies and records, the pattern of Holocene precipitation/moisture variations in the region remains unclear. A lake-sediment-based reconstruction of runoff variations, which can directly and sensitively reflect changes in precipitation, provides the opportunity to reconstruct the evolution of moisture conditions in the SE Tibetan Plateau during the Holocene. In this study, we used a well-dated sediment core (LGH2) from Lake Lugu, a deep alpine lake charged mainly by precipitation on the lake surface and by runoff from the watershed, to reconstruct variations in runoff during the Holocene. In addition, 70 lake surface sediment samples were collected to examine the spatial variation of grain size. Endmember modeling analysis of the grain-size data was used to characterize the processes of sediment transport and runoff fluctuations. The carbonate content of core LGH2 shows that the lake level was generally high during 11,600–3100 cal years BP, and that the lake basin was closed after 3100 cal years BP and semi-closed since 90 cal years BP. Grain-size endmember EM 3, which represents the runoff input clastic materials, is used to reconstruct runoff fluctuations in the Lake Lugu watershed. The record indicates a gradual increase in runoff during 11,600–9000 cal years BP, stable and high runoff during 9000–2000 cal years BP, and weak runoff and a low lake level since 2000 cal years BP. Our reconstruction of runoff fluctuations tracks changes in regional temperature and tropical SSTs rather than in boreal summer insolation. This finding supports the hypothesis that increasing tropical SSTs strengthened ITCZ convection which enhanced the flux of water vapour from the ocean to the air, and hence the moisture supplies to SW China.

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Luminescence Dating of Relics in Ancient Cities Provides Absolute Dates for Understanding Human-Land Relationships in Qinghai Lake Basin, Northeastern Tibetan Plateau

Frontiers in Earth Science ◽

10.3389/feart.2021.701037 ◽

2021 ◽

Vol 9 ◽

Author(s):

Manping Sun ◽

Yongjuan Sun ◽

Haicheng Wei ◽

Guangliang Hou ◽

Ji Xianba ◽

...

Keyword(s):

Tibetan Plateau ◽

Ming Dynasty ◽

Han Dynasty ◽

Central China ◽

Qinghai Lake ◽

Lake Basin ◽

Lake Area ◽

Northeastern Tibetan Plateau ◽

Southern And Northern Dynasties ◽

Qinghai Lake Basin

The study of ancient city sites provides valuable evidence for understanding human-land relationships. Qinghai Lake Basin, on the northeastern Tibetan Plateau, was a key location for economic and cultural exchanges between East and West in ancient China and archaeological surveys have identified the remains of many ancient cities. Although there are relatively good historical records for some ancient cities, their absolute ages are still unclear due to a lack of systematic chronological dating. In this study, OSL dating of ceramic and tile remains from three ancient cities in Qinghai Lake Basin, Xihaijun (XHJGC), Beixiangyang (BXYGC), and Fuxi (FSC), was combined with documentary and paleoclimate evidence to investigate historical human-land relationships. Relics from XHJGC and BXYGC were dated to 0–220 AD, in the Han Dynasty, while tiles from FSC were dated to 120–520 AD, largely corresponding to the Wei Jin Southern and Northern Dynasties. Luminescence ages were generally consistent with dates recorded in historical documents, indicating that the OSL method can be reliably used to date buried tiles in ancient cities on the northeastern Tibetan Plateau. Comparing the dates with paleoclimatic records suggests that the warm and humid climate at c. 2 ka was an important driver of immigration to the region that led to the construction of cities in the Qinghai Lake area during the late Western Han Dynasty. During the Wei Jin Southern and Northern Dynasties (220–589 AD), communication between East and the West flourished, and human activities in the area were strong with the continuation of the war in Central China and Hexi Corridor. Fuxi was largely abandoned in the later Wei Jin Southern and Northern Dynasties, although it was still used intermittently until the Ming Dynasty. Pollen records confirm that humans were extensively engaged in agricultural production in the Qinghai Lake area during the Wei Jin Southern and Northern Dynasties.

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Carbon Dynamics in the Northeastern Qinghai–Tibetan Plateau from 1990 to 2030 Using Landsat Land Use/Cover Change Data

Remote Sensing ◽

10.3390/rs12030528 ◽

2020 ◽

Vol 12 (3) ◽

pp. 528 ◽

Cited By ~ 1

Author(s):

Jingye Li ◽

Jian Gong ◽

Jean-Michel Guldmann ◽

Shicheng Li ◽

Jie Zhu

Keyword(s):

Land Use ◽

Tibetan Plateau ◽

Carbon Storage ◽

Sharp Decrease ◽

Total Carbon ◽

Qinghai Lake ◽

Lake Basin ◽

Ecosystem Carbon ◽

Trade Offs ◽

The Impact

Land use/cover change (LUCC) has an important impact on the terrestrial carbon cycle. The spatial distribution of regional carbon reserves can provide the scientific basis for the management of ecosystem carbon storage and the formulation of ecological and environmental policies. This paper proposes a method combining the CA-based FLUS model and the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model to assess the temporal and spatial changes in ecosystem carbon storage due to land-use changes over 1990–2015 in the Qinghai Lake Basin (QLB). Furthermore, future ecosystem carbon storage is simulated and evaluated over 2020–2030 under three scenarios of natural growth (NG), cropland protection (CP), and ecological protection (EP). The long-term spatial variations in carbon storage in the QLB are discussed. The results show that: (1) Carbon storage in the QLB decreased at first (1990–2000) and increased later (2000–2010), with total carbon storage increasing by 1.60 Tg C (Teragram: a unit of mass equal to 1012 g). From 2010 to 2015, carbon storage displayed a downward trend, with a sharp decrease in wetlands and croplands as the main cause; (2) Under the NG scenario, carbon reserves decrease by 0.69 Tg C over 2020–2030. These reserves increase significantly by 6.77 Tg C and 7.54 Tg C under the CP and EP scenarios, respectively, thus promoting the benign development of the regional ecological environment. This study improves our understanding on the impact of land-use change on carbon storage for the QLB in the northeastern Qinghai–Tibetan Plateau (QTP).

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