摘要
全新世黄土-古土壤剖面保存的木炭屑记录了野火和自然景观演变的过程,本研究通过野外考察采样和磁化率、TOC、木炭屑的实验分析探索陇东黄土高原北部地区全新世野火的历史。研究结果表明：11500aB.P.之前末次冰期,气候干旱,在半荒漠草原植被条件下,自然野火频繁发生;全新世早期（11500~8500aB.P.）野火发生频率大大降低;8500~3100aB.P.为全新世气候适宜期,气候相对比较湿润,生物风化成壤作用强烈,呈现森林草原景观,野火发生几率明显下降,但在古土壤形成早期,木炭屑峰值反映有野火频繁发生,这可能是新石器时代早期老官台文化（8000~7000aB.P.）时期人类用火及其放火烧荒开垦农田等活动的结果;全新世晚期气候向干旱化发展,具有游牧性质的寺洼文化（3250~2650aB.P.）出现在陇东北部黄土高原地区,有一定野火活动。1500aB.P.以后,木炭屑浓度大幅度减少,反映野火很少发生,可能由于本地区半农半牧土地利用方式已经确立,人工-自然复合生态景观形成。
Charcoal preserved in loess-soil profiles in the northern part of the Longdong Loess Plateau has recorded the fire history and landscape evolution connected with climatic variations and human activities. The profile is situated on the isolated fiat-topped Majiayuan loess hill over the Heshui Valley, on the slope of which situated the Jiuzhan Site of the Siwa Culture（3350 ~ 2650aB. P. ）. Archaeological investigations indicate that a large number of graves of the Siwa Culture distribute from the pediment to the upper slopes of the Majiayuan hill. Moreover,the remains of the Laoguantai Culture （8000 ~ 7000aB. P. ）are also identified with the presence of the orange red and browncolored pottery shards, as well as charcoal analysis in the same profile. In this research, samples were cautiously taken every 2cm down the profile. Field investigation and analyses of Total Organic Carbon （TOC） , magnetic susceptibility,and charcoal analysis in this Holocene Loess profile in Heshui, Gansu Province have revealed the relationship among Holocene wildfire events, human activity, and climatic changes. The results show that before 11500aB. P.,the climate was arid and wildfire occurred frequently over semi-desert grassland. The frequency of wildfires was reduced during the early Holocene. During the Holocene climatic optimum between 8500aB. P. and 3100aB. P.,natural wildfires were rarely found. Pathogenic alteration to the accumulated dust processes were so active that forest-grassland formed under the humid warmer climate of the Holocene Mega Thermal. However, localized wildfires in connection with human activities frequently occurred. Fire seemed to be applied to vegetation clearance for land reclamation for millet cultivation in the early Neolithic Age（8000 ~ 7000aB. P. ）During the Late Holocene（3100aB. P. ~ 0）, the wildfires events occurred less frequently and soils were deteriorated due to an abrupt climatic reduction and intensive human activities. Land-use was shifted from arable farming to nomadic in the
出处
《第四纪研究》
CAS
CSCD
北大核心
2008年第4期733-738,共6页
Quaternary Sciences
基金
国家自然科学基金项目(批准号:40571154和40771018)资助
关键词
黄土高原
全新世
环境变化
野火
木炭屑
Loess Plateau, Holocene, environmental change, wildfire, charcoal
