西藏台错古湖沉积物中的硅藻及其古环境  

The Study on the Diatoms of the Palaeolake Sediments and Its Palaeoenvironments in Dahyab Tso (Taicuo) Lake, Xizang (Tibet)

作　　者：李家英[1] 郑锦平[2] 魏乐军[2] 

机构地区：[1]中国地质科学院地质研究所,北京1000372 [2]中国地质科学院矿产资源研究所盐湖资源与环境开放研究实验室,北京100037

出　　处：《地质学报》2005年第3期295-302,i001-i002,共10页Acta Geologica Sinica

基　　金：大地调重点项目"西藏羌塘盐湖资源评价"(编号DKD9902004);国家自然科学基金重点项目(编号498233010)资助的成果

摘　　要：根据硅藻组成、丰度及其生态特征的研究,可以恢复西藏台错古湖地区的古气候演变:在17.8～16.0kaBP经历了气候严寒期;16.0～13.9kaBP为回暖期;在11.5～10.7kaBP气候发生波动性变化,从较暖湿期到寒冷干旱的新仙女木期;在10.4～9.0kaBP气候略有变化,但总体上仍处于寒冷干旱期;在9.0～8.2kaBP转为为凉干期;6.3～5.4kaBP变为暖湿期;在5.4～4.5kaBP变为温暖、干旱期。由此可以看出,该区古气候演变除有仟年级的变化周期外,还可能存在有百年的气候期。自晚更新世晚期以来台错古湖随着古气候的演变,经历了缓慢扩张,湖水变深,而后又缓慢萎缩,湖水变浅,直至强烈的持续干旱,导致湖泊水位的聚降,使湖泊干枯消失。Based on the analysis of diatom record in Dahyab Tso (Taicuo), Xizang (Tibet) by using new indexes of diatom abundance and characteristic, the climatic sequence between 17.80～5.40 ka BP at that area is established, that is: extremely cold period (17.8～16.0 ka BP) —temperate period (16.0～13.90 ka BP)—anathermal(11.50～10.70 ka BP)—extremely cool-dry period (10.40～9.00 ka BP) —dry-slightly cold period (9.0～8.2 ka BP)—warm humid period (6.30～5.40 ka BP)—slightly warm-dry period (5.40～4.50 ka BP). The climatic change stages which revealed by profile of Dahyab Tso (Taicuo) during 17.80～4.50 ka BP, elaborate to be as follows in time order depends with different time scale (such as 1000 year-scale and 100 year-scale).After Late Pleistocene (4.50 ka BP), as the upper part of the profile is missing, saline lake sedimentary record is interrupted. It maght have been explained with the continued vigorously arid incident, making the lake shrink back and causing a water level fall-down.

关 键 词：古湖 硅藻 西藏 古环境 沉积物 古气候演变 新仙女木期 更新世晚期 生态特征 变化周期 持续干旱 湖泊水位 干旱期 BP 波动性 气候期 寒冷 丰度 严寒 暖期 变浅 

分 类 号：Q914[天文地球—古生物学与地层学] P531[生物学—古生物学]