本文關鍵詞： 月球礦物 月球礦物繪圖儀 輻射傳輸模型 月殼成分　出處：《山東大學》2016年碩士論文　論文類型：學位論文

【摘要】：Apollo樣品返回以后,科學家們發(fā)現(xiàn)高地樣品中的斜長石含量非常高(可高達90%以上),因而提出了巖漿洋模型來解釋月殼的形成。模型指出在巖漿洋結晶晚期,斜長石開始結晶并且由于其密度較小而上升到月表,形成了古老的斜長巖質月殼。然而已有的月球樣品采集點主要集中在月球正面,而且分布區(qū)域有限。月球遙感研究則可以從全球化的視角來研究月殼的成分和礦物分布,特別是月球中央峰由撞擊形成,代表了月殼深部的物質。研究不同大小的撞擊坑中央峰,通過撞擊坑直徑-挖掘深度的關系,就可以得到月殼不同深度下的成分和礦物分布,進而對月殼起源的巖漿洋模型進行驗證或者改進。本研究通過建立輻射傳輸模型對月表撞擊坑中央峰的礦物組分進行反演。首先反演得到橄欖石的光學常數(shù)虛部k隨著Fo(橄欖石中Mg/(Mg+Fe)摩爾比)的變化規(guī)律,考慮空間風化效應、月壤孔隙度和背向散射效應對月球光譜的影響,加入SMFe(亞微米Fe),采用橄欖石、單斜輝石、斜方輝石和斜長石四種端元礦物,礦物含量從0%變化到100%,精度為5%,建立礦物混合光譜庫,利用查找表和光譜匹配算法對中央峰的礦物模式進行反演。我們利用月球礦物繪圖儀(M3)數(shù)據(jù)提取了全月101個直徑為～30-200 km的撞擊坑中央峰光譜,并利用輻射傳輸模型對其中86個存在可識別礦物特征的中央峰進行光譜匹配,獲得其礦物組成模式。整體來看,全月中央峰礦物反演結果顯示,月殼中的主要礦物為斜長石,主要鎂鐵質礦物為斜方輝石,其次為橄欖石和單斜輝石,與高地樣品的成分研究結果一致。我們將全月中央峰礦物在長石質高地地體(FHT)、風暴洋克里普地體(PKT)和南極艾肯盆地地體(SPAT)的分布進行針對性分析,發(fā)現(xiàn)：1)FHT的斜長石含量要高于PKT和SPAT,而且FHT所在的月殼厚度明顯大于PKT和SPAT,暗示月殼越薄,鎂鐵質礦物含量越高。2)FHT的中央峰巖石類型主要為純斜長巖、蘇長斜長巖、斜長蘇長巖,和少量的斜長橄長巖,蘇長巖到橄欖石蘇長巖組成；PKT的中央峰主要包含純斜長巖,蘇長／輝長斜長巖,斜長橄長巖和蘇長巖；SPAT的中央峰主要包含輝長蘇長巖,蘇長巖,斜長蘇長巖和純斜長巖。另外,我們在FHT,PKT和SPAT共選擇了6個典型中央峰,利用修正高斯模型(MGM)進一步分析其主要礦物成分信息,結果發(fā)現(xiàn)FHT中央峰鎂指數(shù)較高(Mg'90), PKT中央峰鎂指數(shù)相對較低(Mg'-25-57),而且變化范圍較大。PKT地區(qū)中央峰的鎂鐵質礦物的鎂指數(shù)遠低于鎂質巖套(Mg'80)。SPA撞擊坑的中央峰斜方輝石一般含量較高(30%),主要以蘇長巖為主。我們分別將全月、FHT、PKT和SPAT的斜長石含量(或鎂鐵質礦物含量)與中央峰代表的巖層到月幔距離作關聯(lián),發(fā)現(xiàn)無論是從全球角度還是分三個月球地體來看,斜長石的含量(或鎂鐵質礦物含量)變化與其到月幔距離都沒有顯著地相關性。我們對存在PAN出露的中央峰的月幔距離進行了統(tǒng)計,發(fā)現(xiàn)其變化范圍較大,約為25-60 km。因此月殼中可能并不存在一個純斜長巖地層,或者這個地層已經(jīng)被后期的月幔巖漿侵入作用或一些大型盆地撞擊作用所改造,導致月殼成分在縱向和橫向上都變得不均勻。三大地體的成分在次表層存在一定差異,可能主要是由于其巖漿洋時期的成分和演化階段不同導致,FHT偏鎂,其巖漿演化程度低,PKT偏鐵,其巖漿演化程度高。
[Abstract]:After the Apollo sample return, the scientists found that the plagioclase content highland samples is very high (up to 90%), is proposed to explain the formation of the magma ocean model. The model indicates that the lunar crust in the late magma ocean crystallization, plagioclase began to crystallize and because of its low density and rise to the surface, the formation of anorthositic month old shell. However, samples of moon existing mainly in the lunar surface, and the distribution area is limited. Composition and mineral distribution of remote sensing research can study the moon shell from the perspective of globalization, especially the central peak caused by the formation of the moon, on behalf of the deep crust material crater central. The peak of different size, the relationship between crater diameter - mining depth, can composition and mineral distribution of lunar crust at different depths, and the origin of the magma ocean model on shell for verification or To improve. This study through the establishment of radiative transfer model of the lunar crater central peak mineral component inversion. First inversion of optical constants of olivine in the imaginary part of K with Fo (Mg/ in olivine (Mg+Fe) molar ratio) changes in the law, considering the space weathering effect, soil porosity and the backscattering effect on lunar spectral the effects of adding SMFe (sub micron Fe), using four kinds of olivine, clinopyroxene, orthopyroxene and plagioclase endmember minerals, mineral content changes from 0% to 100%, the accuracy was 5%, the establishment of mixed mineral spectral library, matching on the central peak mineral model inversion using look-up table and spectrum. We use the moon mineral plotter (M3) data. The whole month 101 diameter crater central peak spectra of 30-200 ~ km, and the use of the radiative transfer model of 86 of them have identifiable mineral characteristics of the central peak of the spectrum. With its mineral composition model. Overall, the whole month central peak mineral inversion results show that the main minerals in the lunar crust is mainly mafic minerals are plagioclase, orthopyroxene, and olivine and clinopyroxene, and high sample composition research results. We will full month the central peak of minerals in the feldspathic highlands block (FHT), ocean storm Kerrey (PKT) and Pu body pole Aitken basin body (SPAT) distribution for the analysis, it is found that: 1) the content of plagioclase FHT was higher than that of PKT and SPAT, and the shell thickness of FHT months was significantly higher than that of PKT and SPAT, suggesting that the lunar crust is thin, magnesium the higher the content of iron mineral.2) central peak rock type FHT mainly for pure anorthosite, Su Xie Changyan, Su Changyan and a small amount of plagioclase plagioclase, troctolite, olivine norite to norite; PKT central peak consists mainly of pure anorthosite, Su Hui Long / long oblique 闀垮博,鏂滈暱姍勯暱宀╁拰鑻忛暱宀╋紱SPAT鐨勪腑澶嘲涓昏鍖呭惈杈夐暱鑻忛暱宀，

本文編號：1518569