辽东—吉南地区硼矿床地质特征及成矿规律

辽东—吉南地区硼矿床产于早元古代辽东裂谷中,有硼镁石、含磁铁矿-硼镁石和磁铁矿-硼镁石3种矿床类型,分别赋存于下元古界宽甸群砖庙组下段、老营沟组中段和高小岭组下段,形成3个含硼原始沉积旋回,具严格的层控特点。裂谷阶段沉积的矿源层硼组分,溶于吕粱运动的区域变质和混合岩化的变质热液中,并在该时期的东西向褶皱层间剪切作用控制下,顺层侵位于褶皱翼部低压空间和轴部虚脱部位。成矿后构造对矿床具一定的改造作用,从而形成多成因多期次的沉积变质再造硼矿床。

GEOLOGY AND MINERALIZATION OF BORON DEPOSITS ACROSS EAST OF LIAONING AND SOUTH OF JILIN REGION

Boron mineralizations along the Liaodong rift across the east of Liaoning andsouth of Jilin region yielded three deposit types:ascharite,magnetite-hearing aschariteand magnetite-ascharite.These three types represent three different horon-containingsedimentary cycles and developed at the lower Zhuanmiao series of the KuandianGrorp(lower Proterozaic),the middle Laoyinggou series and the lower Gaoxiaolingseries,respectively.Mineralization modle suggested for these deposit point out thatboron hearing materials of the rift sediments first incarparated into meta-hypothermalfluids associated with regional metamarphism and migmatization during the Lüliangmovement and then,govrned by shear forces divided from EW-trending folding atthat time,passed along straitigraphic planes into low presure zones along the flanks ofthe folds and into collapsed places at the area,to finally precipitate down.Post-mineralization tectonics put a strongly deformation on the regional bodies and gavethem polygenetic and polycyclic characters.In this way,came such boron deposits astypical of first sedimentation then metamarphism,then deformation.