月球和地球上玄武岩浆冷却速率差异的数值模拟  

Numerical simulation of the difference in cooling rates of Moon and Earth basaltic magmas

作　　者：支羽萧 石耀霖 ZHI YuXiao;SHI YaoLin(College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Computing Geodynamics,Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大学地球与行星科学学院,北京100049 [2]中国科学院计算地球动力学重点实验室,北京100049

出　　处：《地球物理学报》2025年第2期595-608,共14页Chinese Journal of Geophysics

基　　金：国家自然科学基金面上项目(41774106)资助.

摘　　要：月球表面约有17%的区域被玄武岩覆盖,地球表面也有70%左右的面积为岩浆喷发至地表在大气或海水中冷凝的玄武岩.但月球与地球不同的是,月表大气非常稀薄,岩浆表面热环境主要由热辐射控制.本文研究了在地球与月球表面不同冷却机制影响下,玄武岩浆冷凝过程的差异.本文仅模拟分析层状静止的熔岩体在地球空气对流冷却和月球辐射冷却两种不同条件下的冷凝过程.通过数值模拟熔岩的冷凝过程,发现月球辐射边界条件下熔岩表面的冷却速率是地球对流边界的500倍以上.冷却速率控制着晶体生长形态及矿物成分,月球辐射冷却条件下熔岩表面到5mm深度处快速淬灭成玻璃体,而地球熔岩浅表则多冷凝为以单斜辉石为主要矿物的玻璃体玄武岩.对熔岩冷却的影响差异主要集中在表面0.5m范围内,更深部的冷却速率则无显著差异.Basalts are the most common feature on the surface of the terrestrial planets,covering approximately 17%of the Moon,and 70%of the Earth.The thermal condition at the lava surface on the moon is primarily influenced by thermal radiation.This paper investigates the differences in cooling and crystallization history of basaltic lava under different dominant cooling mechanisms on Earth and the Moon.The study examines the crystallization process of static lava under two thermal conditions:convection-dominated on the Earth and radiation-dominated on the Moon.The results indicate that the cooling rate of the lava surface is over 500 times faster under lunar radiation boundary conditions compared to Earth.The cooling rate determines the patterns of crystal growth and mineral composition.Under lunar radiation conditions,the surface lava cools rapidly to form glassy material up to a depth of five millimeters.In contrast,the shallow-surface lava on Earth mostly crystallizes to pyroxene glassy basalts.The cooling history varies significantly within 0.5 meters of the lava,while there is little difference at greater depths.

关 键 词：月表玄武岩 冷却过程 冷却速率 晶体形态 矿物组分 

分 类 号：P554[天文地球—构造地质学]