Minor element variations during the past 1300 years in the varved sediments of Lake Xiaolongwan, north-eastern China

Abstract

Synchrotron radiation X-ray fluorescence measurement provides a nondestructive in situ analysis of elements. We present a high-resolution minor element dataset covering the past 1300 years from the varved sediments in Lake Xiaolongwan. The variations of lithogenic elements (Rb, Sr, Ti, Zn, As and Fe) in the lake sediment show distinct decadal to centennial features during the past 1300 years. The Medieval Warm Period has a low value of lithogenic elements. In contrast, the Little Ice Age may be a period with stronger physical weathering and a higher value of lithogenic elements. Principal components analysis of our geochemical dataset suggests a link between high Rb/Sr ratio and Zr abundance in the sediment that could be related with both chemical weathering process and dust input. The variations of biogenic bromine (factor-3) show a pattern similar to the decadal drought index in Korea. Wet conditions favor bromine accumulation in lake sediment because high precipitation may transport more bromine from forest soil and increase plankton production in the lake. Spectral analysis of factor-3 yields notable periodicities of 2.6, 3.5, 53–55, 87–89 and 105–110 years, implying that precipitation variability for the past 1400 years could be associated with El Niño–Southern Oscillation and solar activity.

Keywords::

• varved sediment
• Lake Xiaolongwan
• synchrotron radiation X-ray fluorescence
• bromine

Acknowledgements

We are grateful to the members of the SSRF and Beijing Synchrotron Radiation Facility. We would like to thank two reviewers and Dr Pierre Francus (editor) for their constructive comments and correcting our English. This study was supported by the Natural Science Foundation of China (grant no. 40972121), Research Program of China (973 Program, 2010CB950201) and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA05080400). This paper stems from a presentation at the 3rd PAGES (Past Global Changes) Varve working group workshop, held in March 2012 in Mandersheid, Germany.