南极-艾肯盆地Th异常的富集特征和机理  

The South Pole-Aitken basin thorium anomaly and its enrichment characteristics and mechanisms

作　　者：焦中虎[1,2] 刘少峰[1,2] 奚晓旭[1,2] 韦蔚[1,2] 吴志远[1,2] 李力[1,2] 

机构地区：[1]地球科学与资源学院,中国地质大学(北京),北京100083 [2]中国地质大学地质过程与矿产资源国家重点实验室,北京100083

出　　处：《中国科学：物理学、力学、天文学》2012年第1期95-106,共12页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家高技术研究发展计划重点项目(编号:2009AA122201);国家自然科学基金重点项目(批准号:41030318,91114203)资助

摘　　要：遥感探测表明月表Th元素分布存在全球不均衡性,形成分别以雨海-风暴洋和南极-艾肯(SPA)盆地为中心的Th异常区.研究认为雨海-风暴洋的Th主要来源于对其下覆KREEP物质的开掘,但对SPA盆地的Th来源有各种不同的认识.本文通过对SPA盆地的地形、盆地构造、撞击坑分布、火山作用和地球化学特征的分析,以及对Th富集机理的探讨,认为SPA盆地内Th更可能来源于撞击作用对富Th下月壳物质的开掘;Th的弧形富集特征与盆地构造有很大相关性,并可能受到Apollo盆地形成的影响.The result of remote sensing to the lunar surface shows that the distribution of thorium exists in global imbalance,forming two thorium anomaly regions in Imbrium-Procellarum and South Pole-Aitken（SPA）basin respectively.It is generally believed that thorium in Imbrium-Procellarum is derived from the KREEP layer underlying crust by Imbrium impact,but there are various explanations for the origin of thorium in SPA.Through the analysis of the geomorphology of SPA,basin structure,the distribution of craters,volcanism,geochemical characteristics,and the discussion of thorium enrichment mechanisms,this paper argues that it is more likely that in SPA basin elevated thorium abundances stem from thorium-rich lower crustal materials exposed by the SPA impact event and there is an intimate relation between curve pattern of thorium enrichment and basin structure with a probable impact of Apollo basin formation.

关 键 词：Th异常 南极-艾肯盆地 富集特征 富集机理 KREEP 月球 

分 类 号：P184.5[天文地球—天文学]