幔源包体的形态、大小与寄主岩浆流变学性质的关系

RELATION OF SHAPE, SIZE OF MANTLE-DERIVED ENCLAVES WTTH RHEOLOGIAL PROPERTIES OF THEIR HOST MAGMAS: ILLUSTRATED BY FOUR FNCLAVE OCCURRING AREAS OF SOUTHEASTERN COAST OF CHINA

对东南沿海４个包体产地的玄武岩中橄榄岩包体的形态、大小、向椭球体转变的程度等统计分析表明，幔源包体在上升期间与岩浆作用的过程中，不仅有棱角圆化的现象，而且伴有由等轴体（近似为球体）向椭球体转变的过程。其主要原因是包体在相对岩浆运动的过程中，包体的表面与岩浆之间的粘滞摩擦造成的。粘滞摩擦力的大小、作用于包体表面的时间又取决于岩浆的粘度、包体相对于岩浆的沉降速度、包体半径的大小及岩浆上升的速度，所以这些因素将决定包体变形（磨蚀、椭球化）的程度。因此，可用包体与岩浆相互作用的物理过程来模拟包体的变形特点。

The statistical analysis of the shape, size of mantle-derived enclaves from four enclave occuring areas in southeastern coast of China show that both the round and oval enclaves are accompanied with the ascent of host magma. It is mainly resulted from the viscous friction between the surface of enclaves and the host magmas. And the viscous friction force and the time it acted to enclaves depend on the viscosity of host magma, the settling rate of enclaves compared to magma, the size of enclaves and the ascent rate of magma. All of these properties, therefore, affect the ovalshaped degree of mantle-derived enclaves . Thus the deformation of enclaves are modeled with physical process of the interaction between enclaves and their host magmas. As the result, the real ascent rate of the host magma with the field data about the size deformation degree can be determined.