| 引用本文: | 刘演,李茂田,孙千里,陈中原.中全新世以来杭州湾古气候、环境变迁及对良渚文化的可能影响.湖泊科学,2014,26(2):322-330. DOI:10.18307/2014.0220 |
| LIU Yan,LI Maotian,SUN Qianli,CHEN Zhongyuan.Palaeoclimatic and environmental changes since the Mid-Holocene in the Hangzhou Bay and their possible impacts on the evolution of Liangzhu Culture. J. Lake Sci.2014,26(2):322-330. DOI:10.18307/2014.0220 |
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| 中全新世以来杭州湾古气候、环境变迁及对良渚文化的可能影响 |
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刘演1, 李茂田2, 孙千里2, 陈中原2
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1.华东师范大学地理系, 上海 200062;2.华东师范大学河口海岸学国家重点实验室, 上海 200062
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| 摘要: |
| 利用在杭州湾西部良渚古城遗址附近获取的沉积物岩芯,试图通过高精度加速器质谱(AMS)测年以及多气候、环境代用指标的分析来揭示中全新世以来良渚地区的气候、环境变迁历史,进而讨论其与良渚文化消亡的可能联系.对沉积物的有孔虫分析显示:在大约7500 5200 cal a B.P.期间,研究区为富含有孔虫的潮滩相沉积环境;而约5200 cal a B.P.以来,有孔虫逐渐消失,反映了研究区逐渐脱离海水影响成陆的过程.孢粉记录显示:研究区在约5200 5000 cal a B.P.期间以常绿、落叶阔叶植被为主,伴有少量针叶植被,气候总体上相对暖湿.而在大约5000 4000 cal a B.P.期间,针叶植被的相对增加总体反映了趋于凉湿的气候.在约4000 1500 cal a B.P.期间,虽然常绿阔叶植被重新占据相对优势,但总体呈现逐渐减少的趋势,同时落叶阔叶类植被增加,表明了趋暖偏干的气候;同时,该段水生草本、蕨类植被和藻类的相对增加或许反映了研究区下垫面开始沼泽、湿地化的趋势.约1500 400 cal a B.P.期间,木本植被整体呈减少趋势,陆生草本植被则大量增加,针叶植被进一步减少,表明气候进一步趋干;同时,水生草本和藻类的急剧增加,可能反映了湿地化加剧的状况.最近约400 cal a B.P.以来,针叶植被急剧增加,常绿阔叶植被减少,可能反映了气候突然变冷的过程.岩芯下段禾本科孢粉(>40μm)的出现与研究区脱海成陆的时间相吻合,这表明良渚时期(大约5000 4000 cal a B.P.)研究区水稻种植已有一定规模.但在大约4000 cal a B.P.前后的良渚文化末期,禾本科孢粉浓度一度出现降低,这可能反映了研究区人类活动强度的减弱,其与良渚文明衰落的时间基本吻合.总体上看,这一变化发生在趋干的气候背景以及沼泽化、湿地化加剧的下垫面条件下,暗示了气候、环境因素对良渚文明的衰落可能具有重要影响. |
| 关键词: 中全新世 杭州湾 古环境演变 古气候 孢粉 良渚文化 |
| DOI：10.18307/2014.0220 |
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| 基金项目:国家自然科学基金项目(41272194,41271520);河口海岸国家重点实验室创新团队项目(44105141)联合资助 |
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| Palaeoclimatic and environmental changes since the Mid-Holocene in the Hangzhou Bay and their possible impacts on the evolution of Liangzhu Culture |
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LIU Yan1, LI Maotian2, SUN Qianli2, CHEN Zhongyuan2
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1.Department of Geography, East China Normal University, Shanghai 200062, P. R. China;2.State Key Laboratory of Estuary and Coastal Research, East China Normal University, Shanghai 200062, P. R. China
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| Abstract: |
| A 3.20-m sediment core was obtained near the Ancient Liangzhu City, west of the Hangzhou Bay. AMS dating and multiple proxies were applied to reveal the climate and environmental changes since the mid-Holocene in Hangzhou Bay and their possible impacts on the Liangzhu Culture (ca. 5200-4000 cal a B. P.). It indicated that the enrichment of foraminifera during ca. 7500- 5200 cal a B. P. demonstrated a tidal flat environment. While, the disappearance of foraminifera since ca. 5200 cal a B. P., suggested the initiation of freshwater environment. During ca. 5200-5000 cal a B. P., both evergreen and deciduous broad-leaved vegetation dominated, followed by few coniferous vegetation, indicating a relative warm-wet climate condition. During ca. 5000-4000 cal a B. P., an increase in coniferous trees showed a cool-wet climate setting. The evergreen broad-leaved vegetation prevailed during ca. 4000-1500 cal a B. P. as the coniferous vegetation declined, suggesting a warm and dry climate condition. Meanwhile, the increases in hydrophytic herb, fern and algae proportions exhibited a freshwater marsh environment. During 1500-400 cal a B. P., a magnificent decline in arboreal vegetation, Pinus, in particular, was witnessed as well as the increase in herbaceous vegetation, implying an enhanced dry climate condition. Meanwhile, the increases in hydrophytic herbs and ferns would reflect the muddy environment. The recent 400 cal a B. P. witnessed a sharp increase in coniferous vegetation against the evergreen broadleaved vegetation, reflecting a period of climate cooling. The Graminea (> 40 μm) pollen had been found since the last 5000 cal a B. P. indicating consecutive rice cultivation in the west of Hangzhou Bay. However, concentration of Graminea decreased during the transition of Late Liangzhu (ca. 4000 cal a B. P.) to subsequent Maqiao Culture (ca. 3900-3200 cal a B. P.) when the climate became relatively cold-dry. The coincidence of cold-dry climate, expanded freshwater marsh land and depressed human activities implied by the fall of Graminea proportion after ca. 4000 cal a B. P. suggested the possible linkages of environment and climate change to the fall of Liangzhu Culture. |
| Key words: Mid-Holocene Hangzhou Bay palaeoenvironmental change palaeoclimate pollen Liangzhu Culture |
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