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Climatic sub-cycles recorded by the fourth paleosol layer at Luochuan on the Loess Plateau
- Tieniu, Wu, Guangyong, Lu
- Environmental earth sciences 2012 v.66 no.5 pp. 1329-1335
- calcium carbonate, climate change, ice, isotopes, loess, paleosolic soil types, China
- The Chinese loessâpaleosol succession, deep-sea sedimentary sequences and ice cores are the three types of paleoclimatic records. Measurements were made of the ancient climatic proxies of magnetic susceptibility, median diameter of grain size and contentÂ >40Â Î¼m, and the CaCO3 content of samples collected at 1Â cm depth intervals in the fourth paleosol layer of the Luochuan loess-paleosol section on the Chinese Loess Plateau. Wavelet analysis of the data identified cycles of climate change, which were compared to the marine Î´18O record of SPECMAP. The results showed that: (1) when the fourth paleosol layer was forming, the paleoclimate was relatively stable but five extreme climatic events were identifiable as occurring around 408, 381, 376, 368 and 361 kaBP; (2) two of these regional events differed from the global trend; (3) during marine isotope stage (MIS)11, the fourth paleosol layer of the Luochuan loess section recorded a regional quasi-19Â ka climatic sub-cycle and (4) this sub-cycle was also reflected globally in the SPECMAP data indicating that, during MIS11, this sub-cycle was regionally and globally synchronized.