现代风成沉积物磁化率各向异性与风向关系的研究  

A STUDY ON THE RELATIONSHIP BETWEEN MAGNETIC ANISOTROPY OF MODERN EOLIAN SEDIMENTS AND WIND DIRECTION

作　　者：吴海斌[1] 陈发虎[1] 王建民[1] 曹继秀[1] 张宇田[1] 

机构地区：[1]兰州大学地理科学系,兰州730000

出　　处：《地球物理学报》1998年第6期811-817,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金!49571065

摘　　要：通过对风洞及室内模拟定向风条件下的风成沉积物磁化率各向异性与风向之间关系的研究，发现风成沉积物磁化率各向异性的长轴方向的偏角不仅与风向有关，而且与粉尘沉积量有关。风成沉积物磁化率各向异性的长轴方向的偏角在α95（α95≤20°）的区间范围内与粉尘沉积量大的风向一致．在干旱、半干旱区，现代风成沉积物（沙丘、黄土的表层土）的磁化率各向异性的长轴方向的偏角在此范围区间内与常年盛行风向一致，尤其与沉积物沉降时的盛行风向一致．A wind tunnel experiment and three other experiments about simulating eolian (loess and desert sand) sedimentation were conducted to inveshgate the relationship between wind direction and maximum axis direction of magnetic anisotropy of eolian sediments. Magnetic anisotropy of modem surface soil from Loess Plateau and of dune sand from desert in arid area were also measured in order to furtherly study the relationship under natural condition. The results of the simulation experimentS show that declination of maximum axis of magnetic anisotropy correlate not duly with wind direction, but also with accumulation. A good correlation exists between declination of maximum axis of magnetic anisotropy and high accumulation wind direction (α95<20°);The results of modern soil and eolian sand indicate that the declination of maximum axis direction of the magnetic anisotropy is the same as the eolian-bearing wind direction obtained from meteorological records. These results lead to the conclusion that declination of maximum axis of magnetic anisotropy of eolian sediment can be used as an indicator of wind transportation direction, especially the direction of eolian dust/ sand-bearing wind.

关 键 词：风成沉积物 磁化率 各向异性 风向 沉积 

分 类 号：P512.21[天文地球—地质学]