天山小尤尔都斯盆地全新世湖相沉积特征与沉积环境研究初步  

THE FEATURES OF HOLOCENE LACSTRINE DEPOSITS AND SEDIMENTARY ENVIRONMENT IN LITTLE YOUERDUSI BASIN TIANSHAN MOUNTAINS

作　　者：叶玮[1] 穆桂金[1] 王树基[1] 赵兴有[1] 

机构地区：[1]中国科学院新疆地理研究所,乌鲁木齐830011

出　　处：《干旱区地理》1997年第3期13-20,共8页Arid Land Geography

基　　金：国家自然科学基金!49471010

摘　　要：天山小尤尔都斯盆地湖积物的沉积学与孢粉分析研究表明，全新世以来，该区距今4000年以前及以后至少有两次湖泊发育期。该区域湖泊的兴衰历史表明，全新世环境变化显著，气候呈现冷暖与干湿波动。Youerdusi Basin is an imtermontane basin in Tianshan Mountains. The altitute ranges from 2500 to 2700m a. s. l.. The climate is dry and cold. Kaidu River winds through the.basin and forms wide flood plains. The local permafrost kept the water from going the ground so that the swamplands developed. The vegetation occurs as swamp meadow,meadow steppe and steppe. Besides the alluvial and diluvial deposits, lacustrine deposits distribute extensively in the basin. The locustrine deposits are charchterized by the laminae and peat intercalation. Cut by the river, the lacustrine deposit sequences can be seen clearly in different sections. It is these sedimentary profiles that give us a good chance to study the environmental changes during Holocene in this region. Environmental reconstruction for Little Youerdusi Basin is based on the study of the locustrine sequences. According to the data of lithologic characters, pollen assemblage and radiocarbon dating, it is inferred that the profile records the information of the environmental changes during the last 0. 01Ma in the basin. The results of our study are shown as follows:(1)During Holocene the lake ever occupied he basin twice at last.(2)The lake shrank since middle-Holocene when the climate was warm and dry. The swampland prevailed at the end of the clirnate optimum. As a result, the lake recession sequences were formed. Coinciding with the climatic conditions, bog meadow was dominant in the basin during about 4000 a BP.(3)The 1ake occupied he basin again after 4000 aB. P. and formedt he deposits with laminations, ripples and fossil mollusks. The forest grew in the mountains for a while and the climate was cold and humid.(4)At present, the meandering river develops in the basin and the swamplands distribute widely. The climate is cold and dry.

关 键 词：盆地 湖相沉积 沉积环境 全新世 

分 类 号：P512.3[天文地球—地质学] P534.632