兰州大学机构库
中国西北全新世湿度时空变化集成及区域史前人类活动
Alternative TitleSpatiotemporal changes of Holocene moisture across northwestern 中文na and regional prehistoric human activities
张恩源
Subtype硕士
Thesis Advisor黄小忠
2020-08-02
Degree Grantor兰州大学
Place of Conferral兰州
Degree Discipline自然地理学
Keyword全新世 湿度时空变化 湿度集成 人类活动 中国西北地区
Abstract全新世是地质时代的最新时期,是指距今11700年以来至工业革命结束的气候阶段,又被称为现代间冰期。全新世的气候变化与人类社会发展关系密切,是研究人地关系的重要地质时段。中国西北干旱半干旱区是古丝绸之路的重要通道,生态系统脆弱,对气候变化响应敏感,其地质档案受人类活动影响较小,是研究古气候古环境变化、历史时期人类活动与环境相互作用的理想区域。该区域气候变化(特别是湿度变化)深刻地影响着中国西北部的生态环境、人类活动和社会经济发展。近年来高质量气候代用指标成果和遗址碳十四测年数据不断积累,有必要将最新的单点记录与早期的成果一同进行较大空间范围内的集成研究,从而探究区域气候环境变化与人类活动强度之间的关系。而研究内陆干旱半干旱区域的湿度时空变化,具有一定的学术价值和现实意义,有助于我们应对现在及预测将来气候变化所带来的环境变化和人类生存挑战,实现可持续发展,为国家一带一路和西部大开发战略提供科学参考。 基于此,本论文选取了中国西北干旱半干旱区(新疆、内蒙古西部、甘肃中西部和青海北部地区)56条来自黄土、湖泊、泥炭、树轮和石笋等地质档案的记录,包括具有明确湿度指示意义的孢粉、树轮、黄土-古土壤磁化率、碳同位素和石笋氧同位素等古气候代用指标,将各重建的古湿度序列线性内插至相同的时间分辨率,利用区域平均法对全新世以来和正规化方法对距今一千年以来两个不同时间尺度的湿度序列进行集成分析,并利用反距离权重法分别对两个时段内的湿度等级以千年和百年尺度进行空间插值,以分析该区域湿度的时空变化。此外,本论文收集整理了该区域全新世以来已发表的具有碳十四测年数据的遗址235个、遗址碳十四测年数据820个,用来揭示千年尺度遗址空间分布与数量变化特征,并生成总研究区及子区域的碳十四累积概率密度曲线来反映区域人类活动强度的变化。 本文的研究有助于我们认识全新世以来西北干旱半干旱区湿度变化的时空变化特征,为理解该区域人类活动变化和强度提供了直观且可靠的气候背景。主要结论如下: (1)我国西北干旱地区全新世以来的湿度总体呈现波动上升趋势,即早-中全新世干旱,中全新世变湿,晚全新世最湿润。其中新疆地区的湿度与总研究区变化趋势相近,湿度等级变化显著,而研究区东部(季风边缘区)的湿度集成曲线变化幅度小且无明显变化趋势。研究区内全新世湿度状况存在明显的区域空间差异性,其中季风边缘区的空间差异尤为显著。这可能与亚洲季风深入内陆的程度及西风环流影响范围以及地形因素有关。 (2)研究区千年以来的湿度状况总体表现为波动下降,其中新疆地区的湿度总体呈现波动上升的倾向,研究区东部为波动下降趋势。研究区内湿度状况呈现出明显的区域特征,其中新疆地区千年以来湿度等级的空间差异显著,而研究区东部其内部的湿度等级空间差异近500年来更显著。 (3)新疆地区的集成湿度曲线与碳十四累积概率密度曲线具有较好的一致性,认为湿润的气候条件是促进区域人类活动强度增加的因素之一。而研究区东部的湿度集成曲线变化不显著,且空间差异复杂,湿度与人类活动的关系也更为复杂,可能是因为气候波动促进了人类迁徙及文化技术的交流扩散,进而提高了人类适应环境变化的能力。
Other AbstractThe Holocene is the modern interglacial period starting from 11,700 years ago. Holocene climate change is closely related to the development of human society and thus it is an significant geological period to study human-environment relationships. The arid and semi-arid area in northwestern 中文na is an important area of the ancient Silk Road, where the ecosystem is fragile and sensitive to climate change. Its geological ar中文ves are less affected by human activities, which make it an ideal area to study the changes of paleoclimate, paleoenvironment and the interactions between human activities and environmental evolution in historical period. Climate (especially humidity) change in the region has profoundly affected the ecological environment, human activities and social economic development in northwest 中文na. In recent years, the results of high-quality climate proxies and and radiocarbon dating data of archaeological sites have been continuously accumulated. Therefore, it provides a chance to carry out a comprehensive research in a larger space, together with the latest new records and previous results of climate change and archaeological investigations to explore relationships between regional climate-environmental changes and the intensity of human activities. Studying the spatiotemporal changes of humidity in inland arid and semi-arid regions will help us to cope with environmental changes and human survival chall英语es brought by climate change now and in the future, thus to a中文eve sustainable development. This can provide a scientific reference for the country's "the Belt and the Road" and the Western 中文na Development Strategy. This study selected 56 records from loess, lake, peat, tree ring and stalagmites in arid and semi-arid areas of northwestern 中文na (Xinjiang, western Inner Mongolia, midwestern Gansu and northern Qinghai provinces), including paleoclimatic alternative proxies with clear indication of humidity such as spore pollen, tree rings, loess-paleosol magnetic susceptibility, carbon isotope, and stalagmite oxygen isotope, etc. Each reconstructed paleo-humidity sequence was linearly interpolated for the same time resolution, then we used the regional average method for integrated analysis of humidity series since Holocene, and regularization method for humidity series since one thousand years ago. In order to analyze the Spatiotemporal changes of humidity in the area, inverse distance weighted method is used to separately interpolate the humidity levels in two periods on the scale of millennium and centenary. In addition, this paper collected and explored 820 published 14C dating data from 235 archaeological sites in this region to reveal the characteristics of spatial distribution and quantity changes of the sites and to reveal the regional human activities by generating a cumulative probability density curve of 14C data of the dataset. The main conclusions are listed as follows: (1) The humidity in the arid northwestern region of 中文na generally showed a rising trend with fluctuations since the Holocene, that is, the early-Middle Holocene was drought, then the Middle Holocene became wet, and the late Holocene was the wettest. Among them, the humidity in Xinjiang is similar to the change trend in the general study area, and its humidity level has changed significantly, while the humidity integration curve in eastern part of study area (Asian monsoon marginal area) has a small change range and no obvious change trend. There are obvious regional spatial differences in the Holocene humidity, especially in the marginal areas of the monsoon. This may be related to the extent of Asian monsoon penetrates inland, the influence range of the westerly circulation and topographical factors. (2) Over the last one millennium, the humidity in the study area was fluctuating with a declining trend. The humidity in Xinjiang was generally rising with fluctuations, whereas the eastern part of study area is declining with fluctuations. The humidity in the study area showed obvious regional characteristics. Among which the spatial differences in humidity of Xinjiang has been significant since the millennium, while the spatial difference in humidity levels in eastern part of the study area has been significant since the past 500 years. (3) The integrated humidity curve in Xinjiang is in good agreement with the accumulated probability distribution of 14C dates indicated human activities, and the humid climatic condition is one of the main factors that promotes the increasing of the intensity of human activities. However, the integration curve of humidity in eastern study area does not change significantly, and the spatial difference is complicated. The relationship between humidity and human activities is also more complicated. It is suggested that regional climate fluctuations promoted human migrations and technological exchanges and diffusion, which in turn increased human capacity to adapt to environmental changes.
Pages76
URL查看原文
Language中文
Document Type学位论文
Identifierhttp://ir.lzu.edu.cn/handle/262010/448161
Collection兰州大学
Affiliation资源环境学院
Recommended Citation
GB/T 7714
张恩源. 中国西北全新世湿度时空变化集成及区域史前人类活动[D]. 兰州. 兰州大学,2020.
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