ROCK MAGNETIC-PROPERTIES AND PALEOCLIMATE OF CHINESE LOESS

A typical loess stratigraphy in China consists of alternating loess and palaeosol layers, which potentially provide one of the best terrestrial records of palaeoclimate for the past 2.5 Ma particularly as the magnetic susceptibility record of the loess/palaeosol stratigraphy can be strongly correlated with the climatic fluctuations of oxygen isotope ratios from deep sea sediments. Rock magnetic measurements have verified that magnetite, maghaemite and haematite, are the three most important magnetic minerals. The magnetic susceptibility of Chinese loess varies with changes in both magnetite/maghaemite concentration and grain size. Although the magnetic susceptibility of palaeosols is several times higher than loess, their magnetic fabric has not been enhanced but slightly weakened, which strongly suggests in situ pedogenesis to be the predominant cause of their increased susceptibility.