Climatic shifts, geomorphic change, ancient routes of migration and adaption in southwestern China: Site formation processes at Luojiaba, Sichuan Province
Climatic shifts, geomorphic change, ancient routes of migration and adaption in southwestern China: Site formation processes at Luojiaba, Sichuan Province
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DOI：
10.1002/gea.21950
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发表时间：
2022-12
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影响因子：
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通讯作者：
Junna Zhang;Michael J. Storozum;Weidong Chen;Zongyue Rao;R. Hamilton;Zhexuan Zheng;Zhiyao Chen;Xuetong Yu;Zhengkai Xia
中科院分区：
文献类型：
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作者：
Junna Zhang;Michael J. Storozum;Weidong Chen;Zongyue Rao;R. Hamilton;Zhexuan Zheng;Zhiyao Chen;Xuetong Yu;Zhengkai Xia
考古学家经常将气候变化视为古代人口扩张的驱动因素，但地貌变化也可以在开放或关闭迁徙路线方面发挥重要作用。在中国，考古证据表明，嘉陵江流域的河谷是新石器时代人口从黄河流域向长江流域迁移的重要通道。在这里，我们通过对位于嘉陵江东部支流之一罗家坝考古遗址的沉积学和孢粉学分析相结合，研究河流地貌形态的变化如何影响新石器时代人类进入四川盆地的迁移路径和适应策略。结果表明，人们定居在季节性稳定的地貌上，包括罗家坝的中河漫滩（距今5300-4800年）。他们在靠近河道的河滩前缘进行渔猎活动，并在河滩后缘地势较高的地方建造住宅，不受季节性洪水的影响。我们假设在 5500 cal 之前的全新世气候最适期。 B.P.、强东亚夏季风（EASM）造成的高水位和严重的地表侵蚀堵塞了通往嘉陵江流域上游的通道。只有在 EASM 强度减弱导致一系列寒冷、干燥的气候事件发生之后，大约5500–5000 卡路里B.P.水位是否显着下降。这导致了冲积物的加积，沿着山谷形成了洪泛区和阶地，这可能为进入四川盆地的移民开辟了一条新路线。我们的研究结果揭示了中国西南部高地罗家坝周围的人类-环境动态，并强调了气候-地貌格局的耦合变化对人类住区和生存策略在空间和时间上的影响。
Archaeologists frequently invoke climate change as a driving cause for ancient expansions of human populations, but geomorphic changes can also play an important role in opening or closing routes of migration. In China, archaeological evidence demonstrates that valleys in the Jialing River's watershed were important routes for the movement of Neolithic populations from the catchments of the Yellow River to the Yangtze River. Here, we examine how fluvial geomorphological regime shifts may have also influenced the migration pathways and adaptive strategies of Neolithic people into the Sichuan Basin by using a combination of sedimentological and palynological analysis at Luojiaba, an archaeological site located on one of the eastern tributaries of the Jialing River. The results show that people settled on seasonally stable landforms, including the Zhonghe River floodplain at Luojiaba (5300–4800 cal. B.P.). They carried out fishing and hunting activities on the front edge of the floodplain close to the river channel and built dwelling features on the higher ground at the back edge of the floodplain, which was not affected by seasonal floods. We hypothesize that during the Holocene Climatic Optimum before 5500 cal. B.P., high water levels as well as severe surface erosion caused by a strong East Asian Summer Monsoon (EASM) blocked pathways into the upper reaches of the Jialing River watershed. Only after a series of cold, dry climate events driven by a decrease in EASM intensity ca. 5500–5000 cal. B.P. did water levels recede significantly. This allowed alluvial aggradation to occur, which created floodplains and terraces along the valley that may have opened a new route for the migration into the Sichuan Basin. Our results reveal the human–environment dynamics surrounding Luojiaba in the uplands of southwestern China and highlight the impact of coupled climatic‐geomorphic regime shifts on human settlement and subsistence strategies, across both space and time.