球状花岗质岩石的成因  

The Origin of Orbicular Granitoids

作　　者：曹雨霏 李舒婷 张少兵[1,2] 黄方 CAO Yufei;LI Shuting;ZHANG Shaobing;HUANG Fang(State Key Laboratory of Lithospheric and Environmental Coevolution,USTC,Hefei 230026,China;Center of Excellence for Comparative Planetology,Chinese Academy of Sciences(CAS),Hefei 230026,China)

机构地区：[1]岩石圈演化与环境演变全国重点实验室,中国科学技术大学地球和空间科学学院,合肥230026 [2]中国科学院比较行星学卓越创新中心,合肥230026

出　　处：《高校地质学报》2024年第6期635-645,共11页Geological Journal of China Universities

基　　金：国家自然基金(41973002)资助。

摘　　要：球状花岗质岩石具有独特的球状结构,是一种非常稀有的“地质珍品”,为岩浆过程研究提供了独特的素材。当高温岩浆与低温岩浆接触或者混合时,在接触界面上,由于黏度、温度的差别,界面张力使得高温岩浆可能在低温岩浆中形成球状体,并快速冷却到液相线温度之下,形成较高的过冷度,在挥发分出溶等条件下开始结晶,结晶出的矿物可以呈枝状、羽状等形态,较高的结晶速率导致球体内成分变化很大,进而发育出由不同矿物组成的、颜色深浅不一的交替环带。但是,黏度和温度如何影响成球,成球之后如何结晶,结晶的方式、过程和持续时间,这些问题尚不清楚,都是亟待研究的科学问题。Granitoids with orbicular structure are very rare because of their unique orbicular structure.They stand as unique objects to study magma processes.When high-temperature magma contacted or mixed with low-temperature magma,due to their difference in viscosity and temperature,high interfacial tension leads the high-temperature magma to form orbicules in low-temperature magma.The temperature of orbicules decrease rapidly and result in high degrees of supercooling.Induced by exsolution of volatiles or other factors,the orbicules begin to crystallize and branched or feathery crystals are formed.The rapid crystallization in orbicules results in rapid change of local melt and the alternating crystallization of different minerals,forming dark and light rings.During this process,the crystallized minerals can exhibit branched or feathery structures.However,it is still unclear how viscosity and temperature control spheroidization,and how minerals crystallize after spheroidization,and how long the crystallization process lasts.These issues are waiting to be studied and revealed.

关 键 词：球状花岗质岩石 岩浆混合 过冷 振荡结晶 

分 类 号：P619.222[天文地球—矿床学]