渭河流域全新世以来野火历史与人类土地利用的炭屑记录

全新世黄土沉积中的炭屑通常用来重建野火历史及其演变的过程。通过野外考察和对炭屑以及磁化率等指标的分析，获得全新世野火景观演变过程的地球生物沉积证据。参照OSL/TL、¹⁴C测年和考古学断代数据，重建渭河流域黄土高原全新世以来野火历史以及景观演变过程。结果表明：末次冰期到全新世中期阶段(12 000~3 100 a B.P.)，渭河流域黄土高原地区野火事件变化主要与区域季节性气候差异密切相关，其中千年-百年尺度有效湿度和燃料供给区域变化是野火发生的主控因素；全新世晚期，随着气候进一步干旱，加之人类耕作活动加剧，人类土地利用强度与时空分布已成为影响生物量燃烧规模的重要驱动力。距今3 100 a以来，渭河流域南部地区农田景观已初具规模；而距今约2 170 a，大规模土地开垦已扩展到渭河北部黄土台塬地区；直到距今1 500 a，渭河北部黄土高阶台塬地区旱作农业景观已基本形成。利用多项古生态记录和区域角度综合分析，有助于深入理解该区域野火历史和人类土地利用变化以及社会结构演变过程。

Wildfire History and Human Land Use over Weihe River Basin Since Holocene: Evidence from Charcoal Records

The carbon in Holocene loess deposition is often used to rebuild wildfire history and its evolution process. Through field investigation and the analysis of carbon dust and the magnetic susceptibility index, the earth’s biological sedimentary evidence of wildfire landscape evolution in Holocene is obtained. With reference to OSL/TL dating,¹⁴C dating and archaeology data, wildfire history and landscape evolution process in the loess plateau of Weihe River basin since Holocene is reconstructed. Results show that from the last glacial period to the Middle Holocene stage (12 000-3 100 a B.P.), wildfire changes in loess plateau area of Weihe River basin are mainly associated with regional seasonal climate differences closely, among which the one thousand-one hundred scale effective humidity and fuel supply area change are the main controlling factors of wildfires. In the Late Holocene, with further drought climate, combined with human farming activities, human land use intensity and space-time distribution have become an important driving force to influence of biomass burning scale. Since 3 100 years ago, farmland landscape in the south area of Weihe River has begun to take shape. About 2 170 years ago, the large-scale land reclamation has expanded to the loess tableland area in the north of Weihe River. Until 1 500 years ago, dry farming landscape in loess high order platform tableland areas of northern Weihe River has basically formed. With a number of ancient ecological records and regional point of comprehensive analysis, it helps to understand the region wildfires history, human land use change and evolution of the social structure.