洞穴碳酸钙微层理在中国的首次发现及其对全球变化研究的意义  

DISCOVERY OF MICROBEDDING IN SPELEOTHEMS IN CHINA AND ITS SIGNIFICANCE IN THE STUDY OF GLOBAL CHANGE

作　　者：刘东生[1] 谭明[1] 秦小光[1] 赵树森[1] 李铁英[2] 吕金波[2] 张德二[3] 

机构地区：[1]中国科学院地质研究所,北京100029 [2]北京市地质调查所,北京102206 [3]国家气候中心,北京100081

出　　处：《第四纪研究》1997年第1期41-51,T002,共12页Quaternary Sciences

基　　金：中国科学院PEP-Ⅱ预研究项目;国家自然科学基金;北京石花洞资源开发与环境保护项目

摘　　要：研究我国北部季风气候区石笋的微生长层及其气候意义，在北京石花洞石笋中发现微生长层。通过年代测定、气候事件控制分析，初步提出了石笋微层的年层时标含义及层厚变化主要响应降水变化的气候意义。试图利用微层的层厚－降水响应关系，重建北京地区最近1130年来干湿变化的年分辨率趋势，通过功率谱分析发现136年、50年、16～18年、11年、5．8年的降水周期变化。The stalagmite is a kind of speleothems able to provide climate information with an annual resolution and much longer bine span comparing to tree rings. Two aspects of annual banding of stalagmite have ho reported: the luminescent microbanding observed under a fluoromicroscope and the lamina Which is visible to the naked eye. Rainily, the authors have studied. stalagmites from Beijing Shihua Cave within the East Asian monsoon zone and found that, under the polarizing microscope, the transparent microbanding is also very pronounced The preliminary result shows that there existed about 1 131 continuously microbands at the upper part of the stalagmite-TS9501. Each microband, mostly Ans of micron in thickness, consists of tWo parts: the light zone at its bottom Which may be de posited from the 'old water' which existed in the fissure pushed out by the initial rainfall in a year, and the dark zone on the top which may deposited from the 'freSh water'which came from the covetal soil and contained more organic matter'The Shihua Cave was developed in Ordovician limestone. The stalagmite is about 200mm high and of column-shape. AMS14C dating suggests that the upper 45mm of the stalagmite has an age of not older than 2 000 years B.P. It is clear that the rhythm of each microbanding comparable to the fluctuation of the annual precipitation which possesses only one annual peak value in most years in the monsoon arm and changeS in a wide range similar to that of microbands. The authors have developed a time series according to the microbanding thickness and compared with the record of drought and flood drown from the historical documents of the last 522 years (from 1470 to 1992 yrA.D.) and the instrumental record of precipitation from 1951 to 1980yrA.D. (according to the data from National Climate Center). The coherence of there curves suggests once again that the microbanding is an annual deposition. Conequently, the light and dark parts for each band may reflect seasonal environmental hydrological changes.Baed on the thick

关 键 词：石笋微层 气候变化 全球变化 碳酸钙 

分 类 号：P467[天文地球—大气科学及气象学]