Geomagnetic Relative Polarintensity Dating Of Lake Balikun Sediments

Sediment, of ocean sediments, lake sediments and the loess, etc, can record continuous change of relatively ancient geomagnetic field intensity (RPI). These sedimentary records of RPI from deferent site of the world have a very good consistency. With the increase in the RPI records, the integration of standard RPI curve (Sint-200, Sint-800, and Sint-2000 etc) was taken more and more attention in the the Brunhes period as the millennial scale means of stratigraphic correlation and high precision dating method. At present, the RPI curve from the ocean sediment records to be thought suitable for the RPI study. However, land the distribution of RPI study is extremely rare.Relative to the ocean sediments, lake sediments, has the advantages of good continuity, high deposition rate, widely distributed, and the advantages of easily available, is very suitable for the RPI research. RPI research form lake sediment can make up for the current RPI database uneven geographical distribution of the lack of land, the more validation RPI curve of the various regions of the world can be compared. In this study, we achieve a new RPI from Balikun Lake sediments with a detailed study of the paleomagnetism and rock magnetism in the Northwest China. The new remanence normalized relative intensity of the long-term magnetic field in the study area can provides new record, which set up the relatively ancient geomagnetic field strength in the region change timescale.A detailed rock magnetic and geomagnetic analysis has been conducted on the core BLK11A from the Lake Balikun. The results demonstrate that the core preserve a stable remanent magnetization and meet the magnetic mineral criteria for relative paleointensity (RPI) analyses. The magnetic minerals in the sequence are dominated by pseudo single-domain magnetite and the concentration of magnetic minerals are at the same scale. Susceptibility(x), anhysteretic remnant magnetization (ARM) and saturation isothermal remnant magnetization(SIRM) were used as the natural remanent magnetization normalizer. The RPI data provide a continuous record of the intensity variation during the last 200 ka, which correlates well with the global references RPI stacks. Several prominent low paleointensity values are identified and correlate to the main RPI minima in the SINT-200 record, it suggests that the sediments have recorded the real changes of geomagnetic field. The four polarity drift events prove that the age model of RPI is credible.