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前人的古地磁工作已经证明 ,沉积物的剩磁获得机理十分复杂 .不同条件下不同的磁化过程能否产生与地磁场变化毫无关系的伪磁信号 ,其判别十分困难 .沉积剩磁 (DRM )可能产生倾角误差和地层误差 .沉积后剩磁 (PDRM )可能在沉积物的磁性年龄及沉积年龄之间产生一个滞后 .当沉积物中有不同锁定深度的不同磁相时 ,会使得反转或漂移事件的深度的判别比较困难 ,甚至于产生伪磁信号 .即使在沉积物中只有一个磁相存在 ,但该磁相锁定时间相对于一个倒转 (或漂移 )事件所持续的时间长短不同时 ,所记录的磁信号也会不同 .此外 ,重磁化也可能改变原始的磁记录 ,含水量的变化也可导致磁边界的位移 .所谓的“不稳定孔” ,代表了矿物学上的微小的变化 ,可能产生许多具明显变化的复杂古地磁记录 ,且不能与其他稳定孔的磁记录相比较 .甚至于一些物理扰动 ,诸如生物扰动、变形、钻进过程和干燥效应 ,都可能导致剩磁的改变 .一些古地磁研究已经证明 ,湖泊及边缘海沉积物的磁记录较深海磁记录复杂 ,且均匀的泥及粘土沉积物总是不变地获得较好的古地磁记录 ,而不均匀的砂层则相反 .
Previous paleomagnetic work has proved that the mechanism of residual magnetization of sediment is very complicated.Different conditions under different magnetization can produce a pseudo-magnetic signal that has nothing to do with the change of the geomagnetic field, which is very difficult to discriminate.Depositional remanence DRM) may produce dip errors and formation errors.The residual magnetization (PDRM) after sedimentation may produce a lag between the magnetic age and sedimentary age of the sediments.When there are different magnetic phases with different depths of lock in the sediments, The determination of the depth of a turn or drift event is more difficult or even to produce a pseudo-magnetic signal. Even though only one phase exists in the deposit, the duration of the phase lock in relation to an inversion (or drift) event does not persist At the same time, the recorded magnetic signal will be different. In addition, the re-magnetization may also change the original magnetic recording, the change of water content may also lead to the displacement of the magnetic boundary.The so-called “unstable hole” represents a mineralogical tiny , It is possible to generate many complex paleomagnetic records with significant changes and can not be compared with those of other stable holes. Even with some physical perturbations Bioturbation, deformation, drilling process and drying effect may lead to the change of remanence.A number of paleomagnetic studies have shown that the magnetic recording of lacustrine and marginal sea sediments is more complex than that of deep-sea magnetic recording, and the uniform mud and clay sediments Good paleomagnetic records are always invariably obtained, while uneven sand layers are reversed.