雨海晚期玄武岩的规模研究  

The scale of late-stage basalts in Mare Imbrium

作　　者：陈媛[1,2] 蒋云[3] 张迅与[4] 汤枭[1] 张小梦[1] 蔡伟[1] 罗小星[5] 吴昀昭[1] 

机构地区：[1]南京大学地理与海洋科学学院,南京210023 [2]江苏省地理信息资源开发与利用协同创新中心,南京210023 [3]中国科学院行星科学重点实验室,南京210008 [4]澳门科技大学太空科学研究所 [5]江苏省有色金属华东地质勘查局,南京210007

出　　处：《中国科学：物理学、力学、天文学》2016年第2期40-52,共13页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：中国科学院重点部署项目(编号:KGZD-EW-603);国家自然科学基金(批准号:41172296;41422110);澳门科学技术发展基金(编号:048/2012/A2)资助

摘　　要：月球的岩浆活动揭示了其演化规律.月海玄武岩的规模,反映了月幔的部分熔融程度和源区的深度,对研究月球玄武岩的成因和热演化具有重要意义.月球爱拉托逊纪的岩浆活动在雨海盆地堆积了大面积溢流、光谱独特的高/中钛玄武岩,他们是了解雨海晚期热演化的钥匙.本文基于多种遥感数据,分别利用地形剖面分析法和月坑挖掘深度法,对雨海不同出露情况的各期次晚期玄武岩的厚度和体积进行研究,并简要探讨了喷发通量的变化.研究结果表明,上爱拉托逊纪地层(UEm)厚度为13–33 m,单层熔岩流的厚度为(11±4)m.下爱拉托逊纪地层(LEm)厚度为14.49–43.61 m.将UEm地层的出露体积(~539.3 km^3),LEm地层的出露体积(~5198 km^3)和UEm下伏晚期玄武岩的体积(~556.2 km^3)相加,得到雨海晚期玄武岩总体积为~6479 km^3,远低于Schaber的估计(~4×10~4 km^3).其中,UEm玄武岩出露体积占LEm玄武岩出露体积的比例<1/8,表明雨海爱拉托逊纪玄武岩喷发逐渐减少.本文还基于各UEm单元的出露面积和定年数据,得到了局部雨海晚期玄武岩面积通量的变化:Em5减少了249.56 km^2/Ma,Em6减少了39.49 km^2/Ma,Em7减少了46.89 km^2/Ma,表明雨海晚期的岩浆活动逐渐减弱.The basaltic volcanism is one of the most important geologic processes of the Moon, which reveals its interior evolution. As lunar basalts are formed from the partial melting of mantle materials, the volume of basalts reflects the size and the degree of partial melting of the source region. The Eratosthenian volcanism deposited large scale of high/medium-Ti basalts in Mare Imbrium, which could provide key information for studying the late-stage lunar volcanism in Mare Imbrium. Using a variety of remote sensing data and techniques （topographic profile and crater excavation method）, we studied the scale of the Upper and Lower Eratosthenian （UEm and LEm） basalts in Mare Imbrium. The results show that the UEm is 13-33 m thick with several layers of individual lava （7-15 m） inside, and the thickness of LEm is 14.49-43.61 m. Adding the volume of exposed UEm basalts （-539.3 km3）, the volume of exposed LEm basalts （-5198 km3） and the volume of young basalts underlying UEm （-55 6.2 km3） together, the total volume of the late-stage basalts in Mare Imbrium is -6479 km3. It＇s far lower than that of the Schaber＇s estimation （-4×104 km3）. The volume of the exposed UEm basalts accounts for only about 1/8 of the volume of the exposed LEm basalts, which means that basaltic eruption decreases with time during the Eratosthenian Period in Mare Imbrium. Besides, we estimated the decrease of the areal km2/Ma） and Em7 （46.89 km2/Ma）. These results indicate Eratosthenian Period. flux of Em5-Em7：Em5 （249.56 km2/Ma）, Em6 （39.49 that the basaltic volcanism receded with time during the

关 键 词：月球 雨海 晚期玄武岩 热演化 通量 

分 类 号：P184[天文地球—天文学]