湖光岩玛珥湖沉积物反映的全新世以来古环境演化

HOLOCENE PALEOENVIRONMENTAL EVOLUTION OF THE HUGUANGYAN MAAR LAKE

对广东湖光岩玛珥湖沉积物550℃烧失量(loss on ignition,LOI)和Ti、Al、Si、K元素强度分析表明,烧失量主要反映了流域生产力水平的变化,而Ti、Al、Si、K 4种元素被证明主要来自于流域,反映了径流输入的变化。11 000～7 800cal.aBP,湖光岩地区的气候温暖、湿润;7 800cal.aBP之后,气候迅速变冷、变干,虽然7 800cal.aBP之后气候也发生了一系列的冷、暖波动,但是其温暖程度已远远不及早全新世的水平。湖光岩地区全新世千年尺度气候演化格局和亚洲季风区的其他记录基本一致,即全新世早期为气候适宜期;全新世中、晚期温度降低,气候变干。湖光岩地区全新世中期的降温程度比亚洲季风区其他地质记录的反映更剧烈,这可能是地理位置差异造成的全新世季风演化差异性的体现。湖光岩地区全新世中后期的气候演化过程可能与厄尔尼诺系统存在联系。

LOI 550 ℃（loss on ignition at 550 ℃） and Ti、Al、Si、K intensities of the sediments from the Huguangyan Maar Lake were analyzed for reconstruction of the Holocene paleoenvironmental evolution..LOI mainly reflects the production changes within the drainage basin,whereas Ti、Al、Si、K mainly depend upon the runoff input of the drainage basin.During the period of 11 000~7 800 cal.aBP,the climate at the Huguangyan district was warm and wet.After 7 800 cal.aBP,it quickly became dry and cold.Though there were a series of climatic fluctuations since 7 800 cal.aBP,they were much weaker than those in the early Holocene.Millennial-scale Holocene paleoenvironmental evolution recorded by the sediments of the Huguangyan Maar Lake is consistent with other records in the Asia monsoon area： the climate was optimum in early Holocene,and became relatively colder and drier since the Mid-Holocene.The Mid-Holocene temperature falling reflected by the Huguangyan Maar Lake sediment was much bigger than that from other records in the Asia monsoon area,due to the differentiation of Holocene climatic evolution in different geographical locations.The Mid-late Holocene climatic evolution in the Huguangyan district may have some relationship with the El Nio system.