罗霄山脉山地沼泽全新世以来的古气候记录

在中亚热带罗霄山脉东南段井冈山地区的江西坳山地沼泽钻取了150 cm的岩芯样品（JXA钻孔），通过6个AMS 14C测年结果建立钻孔的年代框架，运用烧失量、腐殖化度、有机碳同位素和灰度值等多项古气候代用指标分析，重建了该地区约11 cal. ka B.P.以来的气候演化历史。结果表明：江西坳山地沼泽的古环境演变过程可以分为４个阶段：11―9.2 cal. ka B.P.钻孔沉积物的有机碳含量低，碳同位素偏负，显示C3植物为主，为气候凉干期；9.2―5.3 cal. ka B.P.碳同位素、有机碳和腐殖化度等指标均指示森林植被繁茂，沉积物泥炭堆积速度加快，为气候最适宜期；5.3―2.2 cal. ka B.P.碳同位素显著变化，有机质含量较高；2.2―0 cal. ka B.P.气候呈现季风再次增强的趋势，人类活动增强。与周边其他的研究结果对比发现：全新世以来罗霄山脉江西坳山地泥炭沼泽的古环境替代指标与低纬度地区其他全新世气候记录基本一致。

Holocene Climate Records from a Mountain Wetland in Luoxiao Ranges

A 150 cm core (JXA) was drilled from a mountain wetland in Jiangxi’ao, Jinggang Mountains in the southeast of mid-subtropical Luoxiao Ranges. Paleoenviromental proxies, such as loss-on-ignition (LOI), humification, organic carbon isotopic and grayscale were used to reconstruct the climatic evolution history in the study area. Based on 6 AMS 14C dating, the age of the sediment at the bottom of the core was ~11 cal. ka B.P.. The sedimentation process could be divided into four stages: 1) During the ages between 11 and 9.2 cal. ka B.P., the content of organic carbon was low and carbon isotopes were characteristic of C3 plants. The climate was relatively cool and dry; 2) in the period of 9.2–5.3 cal. ka B.P., the forest vegetation expanded according to carbon isotope, organic carbon and humification information. The peat land began to develop rapidly, and a warm and humid climate, which corresponded well to the Holocene optimum, was speculated; 3) at 5.3–2.2 cal. ka B.P., the carbon isotope curve showed changes in vegetation components between C3 and C4 plants. The climate was cool and dry; 4) during 2.2–0 cal. ka B.P., the monsoon activity tended to enhance, and the environment was possibly interfered by agricultural activities. The present study provides new paleoclimate evidence in subtropical regions, and indicated the Holocene optimum is between 9.2 and 5.3 cal. ka B.P.. The driving mechanism is mainly controlled by the insolation intensity in the northern hemisphere and summer monsoon variability.