It is of very important significance by using the lacustrine sediments of closed lake in arid area to study its paleoclimatic development. By means of correspondent analysis method to deal with the sporepollen data

the climatic regim over the past ca. 500 Yrs can be resumed quatititatively as follows : in Balikun district

climatic change is predominant by constant warm-drought

and over the past Ca. 500yrs

this distrinct has experienced several climatic periods

5 coldor cool periods

i.e. <1564A. D. 1620～1720A. D. 1750～1810A. D.

1830～1900A. D. and1960～1988A. D.

4 warm periods

i.e. 1588～1620A. D.

1720～1750A. D. 1810～1830A. D. and 1900～1960A. D.. Extensive regional comparison shows that these above～mentioned periods are also displayed in other areas of China

or the world

but it is also of striking regional characteristics

not only of its different begining-termination timings of these periods from those of other areas

but also of its climatic pattern of alternation between warm-drought and cold-or cool-humid differentiating the one of warmhumid and cold-drought in the monsoon affected east China. To a certain extent

Bio-stratigraphieal study of short-chronology will enrich

the contents of the present methods employed for studying short-chronologic environmental development in arid area. Therefore

comprehensive comparisons and verifications by synthetically using these methods will be helpful for us to obtain more precise information on paleoclimatic and environmental changes.