胶东地区重磁场特征及地质解释

GravityMagnetic Field Characteristics and Geological Interpretation in Jiaodong Area

摘要:

本文系统统计了山东胶东地区各地层、岩浆岩的磁化率、剩余磁化强度及密度等物性参数特征，从地质、物性两个角度对区域重磁场特征进行了综合分析。研究结果表明：重、磁场总体走向呈NE—NNE，宏观上反映了胶东地区的地层分布、构造格架和岩浆活动；重力场强度变化较大，跨越（40~40）×105m/s2区间，在胶莱盆地南北两侧表现为重力低，盆地内则反映为重力高；磁场以低缓磁场为主，北、中部场强低、变化小，东南部场强高、变化大。胶东地区重磁场特征反映了该区南部、北部岩浆活动较强烈，中部壳层变薄，基底构造以近EW向、局部构造呈NE向，以及较高密度、较强磁性的古老结晶基底呈带、呈块分布的总体格局。

Abstract:

In this paper, physical parameters， such as magnetic susceptibility, residual magnetization and density of various strata and magmatic rocks in Jiaodong area in Shandong province have been counted systematically. Characteristics of regional heavy magnetic have been analyzed from the aspects of geology and physical properties. It is showed that the overall trend of gravity and magnetic field is NE—NNE, which reflects the stratigraphic distribution, tectonic framework and magmatic activity in Jiaodong area. The intensity of gravity field varies greatly ranging from 40×105m/s2 to 40×105 m/s2 . The gravity is low in the north and south of Jiaolai basin, and the gravity is high inside the basin. The magnetic field is mainly low magnetic field, the magnetic field intensity is low and the change is small in the north and middle. The magnetic field intensity is high and large in the southeast. The characteristics of the heavy magnetic field in Jiaodong area reflect that the magma activity in the southern and northern parts of the area is strong, and the middle crust is thin. The basement structure is EW direction, the local structure is NE direction, and the old crystalline basement with higher density and strong magnetism is zoned.