临夏盆地新生代沉积物岩石磁学记录与亚洲内陆干旱化

ROCK MAGNETIC RECORD OF CENOZOIC LAKE SEDIMENTS FROM THE LINXIA BASIN AND THE ARIDIFICATION OF ASIAN INLAND

临夏盆地毛沟剖面沉积物岩石磁学记录与石英砂颗粒电子扫描研究表明：13.07-8.6 Ma间盆地气候一直保持相对稳定,从8.6 Ma开始,盆地沉积物中流域外的风尘物质开始增加,并经过了6.4 Ma和5.3 Ma的两次加速过程,揭示了我国西北内陆干旱气候可能从8.6 Ma左右开始,且在6.4 Ma和5.3 Ma左右经过两次加强过程。

By means of high resolution research of rock magnetic records and quartz sands from Maogou section in the Linxia basin,we reveal that after a relative stable environment between 13.07 and 8.6 Ma,the basin was gradually influxed by eolian dusts at about 8.6 Ma,and the fluxes of eolian dusts got two rapid increases at about 6.4 Ma and 5.3 Ma respectively.The study suggests that the drying of northwest China began at 8.6 Ma and was strengthened rapidly at about 6.4 Ma and 5.3 Ma.