摘要
1994年9月，在吉林省大布苏湖湖盆东部，获取了总厚度为8．10m沉积剖面样品．以10cm间隔采样．对样品中有机质成分及稳定联同位素研究表明，沉积物中有机质主要来源于陆源高等植物，沉积物中有机物的δ13℃值指示了源生物的特征．在暖干时期，沉积物中有机质具有较高的δ13C值；反之，冷湿时期．沉积物中有机质的δ13C值降低，结合剖面碳酸盐含量及14C年代分析表明，湖区15000年来经历了多期冷湿与暖干的气候旋回，大约距今6700年左右，气候变干并进入稳定的温暖时期，湖水逐渐高度浓缩，形成了现今的盐碱湖。
The organic materials in lake sediments mainly come from (1) autogenous materials (2) allochthonous materials. As in the second case. the organic materials in sediments mainly come from the plants which were brought into the lake by flowing water. So the 813C values of the organic materials are controlled by the plants types. The values of δ13C of the organic materials in sediments can supply the information of what types of plants the organic materials come from.Accordlng to the plant types the paleoclimatic information can be obtained. According to the vertical distribution of the δ13C in Dabusu Lake, has been reconstructed the paleoclimate evoltltion of this region since 15000 years as follows:15400- 14000 aB P (depth 8.10- 7.30m): the climate was cold and wet. During this stage there was a high lake level and stable environment.14000 - 12200 aB P (depth 7. 30~ 6. 30m): the climate was dry and temperate. The lake level descended rapidly.12200- 9500 aB P (depth 6.30-4. 85m): The climate was cold and wet.9500- 7800 aB P (depth 4. 85 - 4. 00m ): The climate came back to warm and dry. and the lake level was low.7800- 5500 aB P (depth 4.00- 2. 80m): The temperature fell and the lake level rose. The climate was cool and wet.Since 5500 aB P (depth 2. 80- 0m): The climate bacame warm and dry. The Lake water condensed rapidly and finally the lake evolved into a saline lake.
出处
《湖泊科学》
EI
CAS
CSCD
1998年第3期8-12,共5页
Journal of Lake Sciences
基金
国家自然科学基金!49702028
中国科学院湖泊专项课题
