安徽省庐江县泥河铁矿重磁异常特征

Characteristics of Gravity and Magnetic Anomalies in the Nihe Iron Deposit of Lujiang County,Anhui Province

泥河铁矿是应用理论找矿、验证磁异常发现的一处大型铁、硫火山岩型矿床。被中国地质调查局评为2008年度十大发现之首,是地质找矿新机制"泥河模式"矿床。重磁勘探在该矿床的发现和普查的过程中发挥了重要作用,重磁异常特征倍受关注。泥河铁矿位于鼻状重力高异常区,剩余重力异常与矿体分布相吻合;原始地磁场以存在△T负异常为特征,△T正异常松散、零乱,与周边异常无明显区别;△T化极异常强度低,经上延或滤波等信息提取处理后形态较好,与矿体分布一致,是验证和矿床普查布钻的重要依据,定量反演计算也在矿床普查过程中发挥了作用。

The Nihe iron deposit is a large-scale iron and sulfur mine of volcanic type. It was found by applying the ore-search theory and verifying the magnetic anomalies. It was appraised as the first in the ten major discoveries in 2008 by China Geological Survey, and as a new mechanism for mineral exploration, the ＂Nihe Model＇. Gravity and magnetic methods have played important roles in the general survey and the prospecting of the deposit, thus the characteristics of gravity and magnetic anomalies received much attention. The Nihe iron deposit is located in an area with high gravity anomalies. In this area, the distribution of ore-bodies coincides with the residual gravity anomalies;original magnetic is characterized by negative Δ T, and the positiveΔ T a- nomalies are loose and disordered without distinct difference from the surroundings. The Δ T reduction to the pole has low intensity, with a better form after upward continuation or filtering,consistent with the distribution of ore-bodies. These are the most important basis for orebody validation and borehole deployment. The quantitative inversion calculation has also played an important role in the general survey.