A Magnetostratigraphic Study of Upper Cenozoic Sediments in Beijing's Gently-sloping Alluvial Piedmont Plain

Through a systemic magnetostratigraphic sampling,testing,analysis and study of the Xin-8 drill hole in the Beijing area,it has been found that the positive polarity and negative polarity intervals reflected in the drill cores can be well correlated with the Brunhes normal polarity,Gauss normal polarity and Matsuyama reversed polarity chrons in the standard polarity column,respectively.The establishment of a high-accuracy and reliable long time-scale chronostratigraphic framework has laid a good foundation for building the 3-D geological struc- ture of the city,and is of great importance in studies of the new tectonic activities,geological evolution history of the plain area,as well as the geotechnical and hydrogeological conditions.