多剩磁成分的主成分法分离及其应用

岩石的多剩磁成分的分离是古地磁研究的重要环节之一.Kirschvink（1980）提出的主成分分析法（PCA）能有效地进行多剩磁成分的方向分离.作者认为,最大角偏差（MAD）值的选择应视各磁成分的剩磁谱组合特征而定,剩磁相似度的提出,可以帮助确定MAD值选取的最佳值.在主成分法分离的剩磁方向的基础上,作者提出了一种多剩磁成分的强度分离方法,籍此可以进一步研究各分离磁组分的剩磁谱特征及其成因,并将以上方法应用于新疆柯坪地区晚古生代地层的剩磁分离.

PRINCIPAL COMPONENT ANALYSIS AND IT'S PALAEOMAGNETIC APPLICATION

Separation of multi-components becomes an important part in paleomagnetism. By employing the method of principal component analysis(PCA) suggested by Kirschvink (1980), we may isolate the directions of multi-components effectively. Special emphasis has been placed on the choice of MAD value with respect to the combination of remanent spectrum. Remanent similarity defined by the authors could help to confine the upper limit of MAD value. Based on the directions of isolated components derived from PCA method, a method for separation of magnetic component in intensities is suggested. Its validity has been demonstrated through examples of pilot specimens of Late Paleozoic from Kepin region, Xinjiang.