磁铁矿与黄铁矿双向交代研究及意义

DUAL METASOMATISM BETWEEN MAGNETITE AND PYRITE AND ITS IMPLICATIONS

在华北盆地南缘早古生代碳酸盐岩中 ,发现了包括交代假象和交代残余在内的一系列足以支持磁铁矿与黄铁矿之间发生过双向交代作用的确凿矿物学证据 ,甚至在同一个磁性矿物颗粒内 ,还辨认出方向完全相反而且是先后发生的 2种交代现象。磁铁矿 (铁磁性矿物 )和黄铁矿 (顺磁性矿物 )之间的双向交代会直接干扰古地磁数据 ,并影响以此为基础而开展的地块运动分析和古地理的重建。

There is convincing mineralogical evidence such as metasomatic pseudomorph and replacement remnants to support that dual replacements have taken place in the Early Paleozoic carbonate rocks form southern part of the Huabei basin. Two kinds of replacements that have proceeded in opposite directions in two different periods were found to occur even in the same grain. The dual opposite metasomatism between the ferromagnetic magnetite and the paramagnetic pyrite would produce noise on the palaeomagnetic data to distort the palaeomagnetic results of a given region,if passed unnoticed.