The Charcoal Record Of Fire History From The Sanjiang Peatlands During The Period From Mid-to Late-Holocene

Under the influence of the East Asian monsoon, the Sanjiang Plainwhich belongs to sensitive area of global change, has been identified as akey region for investigating. In fact, many previous researches aboutpaleoclimate since the Holocene have been done in this place. Most ofthem are focused on pollen analysis. However, the study of the paleofireis still scarce. What’s more, because of the lack of long continuouscarriers and enough age dating date, it is difficult to carry out the regionaland global comparative studies on thousands scale.In order to do the comparative study, we collected the samples fromthe Shenjiadian sediment profile (located in the northeast of the SanjiangPlain) and the Honghe sediment core (situated in the Southwest ofSanjiang Plain) in this dissertation. The age model in the paper is basedon AMS14C dating. Combined with high-resolution charcoal analysis,multiple indicators analysis including dry density and ash content, havebeen applied to reconstruct the period from mid-to late-Holocene fire history and climatic change. Comparing the analyzed results with thehistorical documents, we can reveal the impact of the climate change andthe human activities on the environment during the period from mid-tolate-Holocene. In this study, we draw the following conclusions:(1) The history of fire and the paleoenvironment of Shenjiadian duringthe period from mid-to late-Holocene can be generally divided into4phases. The fire became intensity, and temperature, humidity increasedquickly during7420-3519cal a B.P.. From3519to1422cal a B.P., thefire was relatively stable, and the climate was warm and humid. During1422-727cal a B.P., the occurrence of fire had a great variability, andtemperature, humidity increased more severely. From727cal a B.P. topresent, climate was cool and dry, and due to the impact of humanactivities, the fire activity gradually increased.(2) The fire history of Honghe during the period from mid-tolate-Holocene can be generally divided into5phases, and the climatepresented us an alternating of warm and cold. During the periods of3534-2720cal a B.P.,2193-1855cal a B.P.,1070-905cal a B.P.,494-432cal a B.P. and216-154cal a B.P., the fire showed a high intensity. Andthe peaks of the first four phases corresponded to the warm and humidclimate. While, the intensive fire during the period of216-154cal a B.P.was mainly caused by human activities.The fire history and the environment change around Sanjiang Plain during the period from mid-to late-Holocene was resulted from thecombination of the natural variability and human activities. Our studysuggests that the fire history and the environment change of SanjiangPlain during the period from mid-to late-Holocene was mainly similarwith the global change; while there are differences of environmentchange patterns during the period from mid-to late-Holocene in SanjiangPlain, which indicates the temporal and spatial characteristics of theenvironment change.