Lingtai Loess 7Ma Magnetic Susceptibility, Grain Size, and Carbonate Data Sun, Y.; An, Z.; Clemens, S.C.; Bloemendal, J.; Vandenberghe, J. Sun, Y. An, Z. Clemens, S.C. Bloemendal, J. Vandenberghe, J. Monsoon earth science/paleoclimate/loess (grain size mean,loess,null,micrometer,null,loess,null,null,N,null) earth science/paleoclimate/loess (grain size mean,loess,null,dimensionless,null,loess,normalized,null,N,null) earth science/paleoclimate/loess (proxy composite,loess,null,null,null,loess,composited,null,N,normalized and averaged magnetic susceptibility and carbonate data) earth science/paleoclimate/loess (age,null,null,null,null,loess,null,null,N,null) earth science/paleoclimate/loess (calcium carbonate,loess,null,weight percent,null,loess,smoothed,null,N,3 points smoothing) earth science/paleoclimate/loess (depth,null,null,meter,null,loess,corrected,null,N,null) earth science/paleoclimate/loess (magnetic susceptibility,loess,null,unspecified unit,null,loess,smoothed,null,N,3 points smoothing) earth science/paleoclimate/loess (calcium carbonate,loess,null,dimensionless,null,loess,normalized|smoothed,null,N,3 points smoothing) earth science/paleoclimate/loess (magnetic susceptibility,loess,null,unspecified unit,null,loess,normalized|smoothed,null,N,3 points smoothing) earth science/paleoclimate/loess (Lingtai>LATITUDE 35.0667>LONGITUDE 107.65) Recent studies of the eolian deposits in northern China have extended the East Asian monsoon history back to the early Miocene. However, the relative intensities of monsoonal winds and precipitation and the extent of their coupling prior to the Pleistocene epoch remain poorly constrained, mainly due to uncertainties in the interpretation of proxy indices generated from the Mio-Pliocene Red Clay sequences. Here we reconstruct East Asian monsoon oscillations over the past 7 Ma using magnetic susceptibility and carbonate content as summer monsoon (precipitation) proxies, and quartz grain size as a winter monsoon (wind intensity) index. Our results suggest that precipitation and wind intensity exhibited significant orbital-scale variations prior to 4.2 Ma, followed by slightly damped variability between 4.2 and 2.75 Ma. Subsequently, East Asian monsoon circulation experienced two large shifts at about 2.75 and 1.25 Ma, characterized by stepwise strengthening of glacial wind and interglacial precipitation. A remarkable change in East Asian monsoon seasonality occurred around 3.15-2.75 Ma. Prior to 3.15 Ma, strong winds were positively correlated with high effective precipitation, whereas after 2.75 Ma strong winds were negatively correlated with heavy precipitation. This shift was probably induced by a change from an insolation-forced system to one strongly influenced by the combined effects of the phased uplift of the Himalaya-Tibetan Plateau and the simultaneous development of the Northern Hemisphere ice sheets. STUDY NOTES: Magnetic susceptibility, grain size, and carbonate data for the past 7 million years from the loess-paleosol and Red Clay sequence located at Lingtai on the southern Chinese Loess Plateau. The Quaternary loess-palaeosol sequence (168 m) is underlain by the 120-m-thick late Neogene Red Clay formation. Samples were taken at 8 cm intervals for the loess-palaeosol sequences and 4 cm intervals for the Red Clay formation. A total of 5100 samples were collected for proxy analyses. Magnetic susceptibility was measured using a Bartington MS2 meter at the Institute of Earth Environment, Chinese Academy of Sciences. Carbonate content was determined by a volumetric method, with an error of less than 3%. Particle-size distributions of bulk and quartz samples were determined using a Malvern Mastersize S laser-diffraction analyzer at the Institute of Earth Environment, Chinese Academy of Sciences. Lingtai, Chinese Loess Plateau: 35°04'N, 107°39'E, 1350 m elev. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Sun, Y. Investigator : An, Z. Investigator : Clemens, S.C. Investigator : Bloemendal, J. Investigator : Vandenberghe, J. 2012-05-30 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/12970 https://www1.ncdc.noaa.gov/pub/data/paleo/loess/china/sun2010lingtai.txt https://www1.ncdc.noaa.gov/pub/data/paleo/loess/china/sun2010lingtai.xls https://www1.ncdc.noaa.gov/pub/data/paleo/loess/china/sun2010lingtai.txt https://www1.ncdc.noaa.gov/pub/data/paleo/loess/china/sun2010lingtai.xls English https://www.ncdc.noaa.gov/paleo/study/12970 https://www1.ncdc.noaa.gov/pub/data/paleo/loess/china/sun2010lingtai.txt https://www1.ncdc.noaa.gov/pub/data/paleo/loess/china/sun2010lingtai.xls Sun, Y.B., Z.S. An, S.C. Clemens, J. Bloemendal, and J. Vandenberghe. 2010. Seven million years of wind and precipitation variability on the Chinese Loess Plateau. Earth and Planetary Science Letters, Vol. 297, pp.525-535. doi:10.1016/j.epsl.2010.07.004 START YEAR: 6935000 cal yr BP * END YEAR: 0 cal yr BP 107.65 35.0667 107.65 35.0667