有关密怀地区原四合堂群地质体认识的商榷

Discussion on understanding the geological body of former Sihetang Group in Mihuai area

有学者认为,密怀地区四合堂群层状地质体(表壳岩和铁矿)因受韧性剪切带的剪切作用,变成了一个夹构造残留体的巨大岩浆杂岩体。铁矿体因被剪断、位移、丢失,以至造成矿产的巨大损失,从而影响矿床的工业评价。以铁矿、杂岩体、地层、混合岩化、块状无序的变质岩等为研究重点,多数单位认为,该区可划分出两块面型分布的表壳岩。铁矿勘探,全区获得了十亿吨储量,成果丰硕。四合堂群的铁矿虽然厚度不大,但没有发生被剪切带剪断而丢失的情况,大多数铁矿都稳定的向下延伸了几百米。以事实为据,勘探队认为,对该争议地质体的认识,称岩浆杂岩体不合适,它仍应保留原来的提法,即:四合堂群层状地质体。

Some scholars believe that due to the shear action of ductile shear zone,the layered geological body(surface crust rock and iron ore)of the Sihetang Group in Mihuai area has become a huge magmatic complex intercalated with structural residual body(or structural barrier body).As a result,the iron ore body is displaced and lost due to shearing,resulting in huge loss of mineral reserves,thus affecting the industrial evaluation of the deposit.This paper carries out a comprehensive geological research,focusing on iron ore,complex,stratum,migmatitization and massive disordered metamorphic rocks.The results show that the majority belief is that this area can be divided into two large surface-type distributed surface crust rocks.Iron ore exploration in the whole region has uncovered 1 billion tons of reserves.Although the ore body in the Sihetang Group is not thick,most of the iron ores extends steadily downward for hundreds of meters without much loss due to shear actions.Based on the facts,it is considered that the magmatic complex is not suitable to call this controversial geological body magmatic complex.It should still retain the original name,i.e.,the layered geological body of the Sihetang Group.