摘要
大宁岩体是一个多期次侵入的复式岩体,主要由石英闪长岩、花岗闪长岩和二长花岗岩等花岗质岩石组成,其中富含镁铁质微粒包体(MME),MME主要出露在花岗闪长岩中。花岗闪长岩中部和边部MME个数与单位测量面积的特征值(直径)之间均存在对数线性关系(ρ>0.75),表明MME-花岗质侵入岩体系为分形体。结合MME的形态、结构特征,认为大宁岩体中MME为岩浆混合成因。花岗闪长岩中部和边部MME的分维数分别是1.293和0.991,表明混合程度在空间上具有不均一性。MME长轴展布方向与寄主岩体的原生流动线理方向一致,暗示着在镁铁质岩浆注入之前,长英质岩浆已部分结晶。对流作用可能是MME分布、变形和岩浆混合程度差异的主要驱动力。
The Daning multi-stage intrusive complex mainly consists of quartz diorite, granodiorite and monzo- granite, in which mafic microgranular enclaves （MME） are well developed, especially in granodiorite. Shape, tex- ture and fractals characteristics of enclaves that double logarithmic coordinates of circular diameter of work area and number of MME has a good linear relation （ p 〉0.75）, show MME and the host rocks follow a fraetal model, being indicative of MME of magma mixing origin. It can be speculated that mixing is heterogeneous in space from that the fractal dimension of MME in the interior and margin of granodiorite is 1.293 and 0.991 respectively. A consistent lineation structures between MME and the host rocks suggest that felsic magma had partially crystal- lized before injection of mafic magma. Maybe convection is the main driver for dispersedness, deformation of MME and mixing heterogeneity.
出处
《华南地质与矿产》
CAS
2013年第4期282-291,共10页
Geology and Mineral Resources of South China
基金
中国地质调查局地质矿产调查评价专项(编号:1212011085356
12120113063600
121201122051)
