白云岩之上红色粘土的磁组构特征及其成因指示意义探讨

通过与粉尘堆积,以及玄武岩和片麻杂岩风化剖面磁组构的对比,探讨了以贵州平坝白云岩之上红色粘土剖面磁组构特征及其成因指示意义.红色粘土的各向异性较弱,并且不具有明显的沉积磁组构;母岩的组构特征对红色粘土磁化率各向异性没有明显的控制"痕迹";红色粘土与粉尘堆积物之间磁组构特征的明显差异,表明它们在物源和形成机制方面是不同的;红色粘土磁化率及磁组构特征反映出红色粘土中磁性矿物的物质来源和成因具有一定的特殊性.

FEATURES AND GENETIC IMPLICATION OF THE MAGNETIC FABRIC OF TERRA ROSSA ON DOLOMITE

The relationship of terra rossa to underlying carbonates is a long-standing problem,which has resulted in different opinions with respect to the parent material and the origin of terra rossa.In the paper,the magnetic fabric characteristics of terra rossa overlying dolomite are examined.The terra rossa profile is located at Pingba farm,Pingba county,Guizhou province.For exploring the genesis and provenance of terra rossa,a contrast research among terra rossa,dust sediment and weathering crust of basalt and gneissic complex has been done.The results suggest that the anisotropy of magnetic susceptibility(AMS) of terra rossa is weak and don't have distinct sedimentary magnetic fabric.The AMS of terra rossa is not controlled by the parent rock fabric distinctly.The magnetic fabric of terra rossa is quite different from terrestrial eolian deposition,which indicates that they have different provenance and sedimentary processes. The features of magnetic fabric and magnetic susceptibility of terra rossa suggest that the provenance and the origin of magnetic minerals are of certain specialty.