基于XRF连续扫描的云南抚仙湖沉积物元素特征及环境意义

doi:10.3964/j.issn.1000-0593(2019)07-2223-05

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Abstract X-ray fluorescence (XRF) core scanning has the advantages of simple pre-processing, non-destructive and high precision, and it has been widely used in the high-resolution environmental change studies of oceans, shallow lakes and loess. However, the hydrodynamic processes and the material translocation and transformation of deep lakes are apparently different from shallow lakes, and the research of XRF continuous scanning in deep lake is still relatively few. Based on the analysis of XRF elements continuous scanning of Fuxian Lake sediments, located in the central Yunnan plateau basin, the characteristics of geochemical elements and its environmental significance have been discussed, combined with comparative analysis of XRF core scanning and inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) method, chronology and other environmental proxies. The results obtained are as follows: (1) There is a close correlation of geochemical elements between XRF core scanning and the ICP-OES/ICP-MS methods (p<0.01), except for the element P, Ge and Cr. The correlative coefficient of K, Ca, Ti, Fe, Rb and Zr is more than 0.85. (2) The result of principal factor analysis shows that the variance contribution rates of principal component 1 and 2 are 76.31% and 10.37%, respectively. The principal component 1 is much greater than component 2. The factor loading of K, Fe, Ti, Zn, Rb and Zr exceed 0.9. It indicates that the erosion intensity of Fuxian Lake catchment is the main control factor of the deposition process, and the exogenous detrital elements have a better indicative implications for regional environment change and human activity intensity. (3) Based on the geochemical element analysis by using XRF core scanning and other climate proxies of the lacustrine sediments, the environmental changes and human activities of the central Yunnan plateau basin have been reconstructed since 5 200 cal. a BP. The intensified human activity (e. g. agricultural farming, extensive deforestation) caused a heavy loss of soil of the lake catchment since 2 200 cal. a BP., and the significant increased element contents (e. g. Ti, Rb, Zr) indicated that a large amount of exogenous detritus had been carried into the lake basin. The results of this study can provide references and experience for the application of XRF technology in deep lake, and it will be helpful for the study of high-resolution environmental change and human activities in the Asian southwest monsoon.

Key words：X-ray fluorescence core scanning; Inductively coupled plasma otpical emission spectrometry and mass spectrometry; Environmental change; Human activity; Fuxian lake

Received: 2018-04-25 Accepted: 2018-10-09

ZTFLH:

O657.3

Corresponding Authors: ZHANG Wen-xiang E-mail: wenxiangzhang@gmail.com

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https://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2019)07-2223-05 OR https://www.gpxygpfx.com/EN/Y2019/V39/I07/2223