河北省铁矿分布与重磁场特征的关系

在河北省铁矿资源潜力评价及成矿预测中,对重力场、磁场特征进行了总结和归纳,认为规模较大的航磁正异常主要是出露或隐伏侵入岩基的反映;大面积分布的低缓正磁异常区则主要反映了太古宙变质岩系或基底隆起的边缘,沉积变质型铁矿主要密集分布在此区域;负磁场区主要出现在中上元古界、古生界碳酸盐岩和中生界酸性火山—沉积岩系;强度高、梯度大、或有明显负值伴生的局部磁异常则可能是磁性铁矿的反映。从重力场特征看,磁性铁矿主要分布在布格重力异常的梯级带或异常扭曲处,以及正、负异常的交界处,这些地方多与地质构造强烈变形密切相关。只有对重磁场进行深入地质剖析,结合典型矿床上建立的识别标志进行对比分析,才能得出一个符合客观实际的地质解释。

THE RELATIONSHIP BETWEEN DISTRIBUTION OF IRON DEPOSITS AND CHARACTERISTICS OF GRAVITY AND MAGNETIC FIELDS IN HEBEI PROVINCE

we conclude and sum up on the character of the Gravity and magnetic field in the project on the Hebei province iron ore resource potential evaluation and metallogenic prediction in this paper.The larger positive aeromagnetic anomalies are mainly reflected by the emergence or hidden intrusive batholith;A larger area of distribution of lower and positive magnetic anomalies are mainly reflected by the acidic volcanic rocks in the Archean metamorphic rocks or the edge of the basement uplift zone where the sedimentary-metamorphic iron ores distribute densely;The negative magnetic field is always reflected in the Upper Proterozoic,Paleozoic carbonates and Mesozoic acidic volcanic-sedimentary rocks;The higher,larger gradient,or the local magnetic anomalies associated with the negative may be a reflection of the magnetic iron ore.The magnetic iron ore are mainly distributed in the gravity gradient zone or abnormal distortions and the border between the positive and negative anomalies From the features of gravity,field,where they are closely related to the strongly-deformed geological structure.We can make a realistic geological interpretation only by deep geological analysis on the gravity and magnetic field and comparison analysis combined with the identification marks built in the typical deposit.