The use of the rock magnetic and paleomagnetic data for the Loess Plateau deposits in China for their climatologic and chronologic correlation to the oxygen isotopic timescale

Аннотация

The results of numerous rock magnetic and paleomagnetic studies of Pleistocene deposits in the Loess Plateau in China which were obtained over a period of a few decades are analyzed. It is shown that two important problems remain unsolved. These are (1) developing the particular mechanism of “magnetic enhancement” in the soils, probably with a more accurate assessment of the level of effect of various natural factors causing qualitative changes in the magnetic fraction of the soil. Here, both the chemical composition of the newly crystallized magnetic mineral causing this enhancement and the parameters of the corresponding secondary (chemical) magnetization process should be determined. (2) Fixing the exact climate-stratigraphic position of the main paleomagnetic benchmarks of the Pleistocene, primarily the Matuyama–Brunhes reversal. In contrast to many conclusions, it is inferred that the Pleistocene paleoclimatic loess-soil record in China generally disagrees with the oxygen isotope (OI) record in the deep-sea sediments. This inconsistency is particularly significant for the Matuyama chron deposits.