本文關(guān)鍵詞：月海玄武巖與月球演化　出處：《地球化學(xué)》2010年01期 　論文類型：期刊論文

  更多相關(guān)文章： 礦物學(xué) 地球化學(xué) 月海玄武巖 巖漿海 KREEP 月球演化

【摘要】：月海玄武巖主要產(chǎn)于月球近邊的盆地中,覆蓋面積為月球表面的1%,其形成年齡多在39～31億年之間,是各類月巖中最年輕的。與地球玄武巖相似,月海玄武巖由斜長石、輝石和橄欖石組成,但它們比地球玄武巖具有更低的Mg#、Al2O3、K和Na含量,高的FeO含量(大于16%)和變化范圍大的TiO2含量(小于1%到大于13%)。根據(jù)TiO2含量的變化,月海玄武巖分成高Ti(6%),低Ti(1.5%TiO26%)以及極低Ti(1.5%)三類。所有月海玄武巖都具有Eu負(fù)異常,并虧損揮發(fā)性元素和親鐵元素。月海玄武巖的同位素特征指示其至少為三個組分混合的產(chǎn)物:(1)高238U/204Pb、高87Sr/86Sr和負(fù)εNd組分,可能是巖漿海分異的殘余巖漿即KREEP;(2)低238U/204Pb、低87Sr/86Sr和正εNd組分,來源于原始月幔,其熔融產(chǎn)物為低Ti玄武巖;(3)中等87Sr/86Sr和εNd組分,位于月幔的頂部,經(jīng)歷了巖漿海(洋)過程中形成的堆晶物質(zhì)的再熔融,還可能受到了隕擊事件的影響,其熔融產(chǎn)物是高Ti玄武巖。月海玄武巖的元素和同位素地球化學(xué)性質(zhì)支持巖漿海的假說,其源區(qū)的形成與巖漿海的分異密切相關(guān),并經(jīng)歷了三個階段:(a)巖漿海階段,通過巖漿海的結(jié)晶分異形成頂部為斜長巖月殼,中間為高Ti、富鈦鐵礦層,底部為巨厚的硅酸鹽低Ti層的三層殼幔結(jié)構(gòu);(b)富鈦鐵礦堆晶巖(攜帶少量殘余熔體)因密度大而下沉至下部的硅酸鹽月幔(400km以下);(c)月幔中這些不同源區(qū)的巖石發(fā)生減壓熔融。早期由較淺的低熔點(diǎn)組分熔融形成低K高Ti玄武巖,之后形成來源較深的高Ti玄武巖和低Ti玄武巖。
[Abstract]:Mare basalts occur in the near side of the moon, covering an area of 1% of the lunar surface, its formation at the age of 39 to 3 billion 100 million years, is the youngest of all kinds of rocks. Similar to the earth basalts, the moon sea basalt is composed of plagioclase, pyroxene and olivine, but they have lower Mg#, Al2O3, K and Na contents than the earth basalt. The TiO2 content of the high FeO content (greater than 16%) and the wide range of variation (less than 1% to 13%). According to the changes of TiO2 content, mare basalt divided into high Ti (6%), low Ti (1.5%TiO26%) and low Ti (1.5%) three. All have the mare basalts negative Eu anomaly, and loss of volatile elements and siderophile elements. The isotopic characteristics of mare basalts indicate the product of at least three mixed components: (1) high 238U/204Pb, high 87Sr/86Sr and negative epsilon Nd components may be residual magma differentiation of the magma ocean is KREEP; (2) low 238U/204Pb, low 87Sr/86Sr and positive epsilon Nd components, from the primitive mantle the product is low, the melting of Ti basalt; (3) medium 87Sr/86Sr and epsilon Nd component, at the top of the mantle, magma experienced sea (Ocean) re melting cumulate material formed in the process, may also be affected by the meteorite strike event, its product is high Ti basalt melt. Mare basalts of elemental and isotopic geochemistry of support magma ocean hypothesis, the source region of the formation and differentiation of the magma ocean are closely related, and has experienced three stages: (a) magma sea stage, through the crystallization of magma sea differentiation at the top of the anorthosite in the lunar crust, high Ti, the titanium rich iron ore layer, the bottom three layer of crust mantle structure of thick Portland low Ti layer; (b) rich ilmenite cumulates (to carry a small amount of residual melt) because of the density of large and sink to the lower part of silicate mantle (400km); (c) the homologous decompressional melting of the rocks the mantle. In the early period, the low K high Ti basalt was formed by melting the shallow low melting point components, and then the high Ti basalt and low Ti basalt were formed.
【作者單位】： 中國科學(xué)院同位素年代學(xué)和地球化學(xué)重點(diǎn)實(shí)驗(yàn)室中國科學(xué)院廣州地球化學(xué)研究所;
【基金】：國家自然科學(xué)基金(40721063) 中國科學(xué)院知識創(chuàng)新工程方向性項(xiàng)目(KZCX2-YW-T004)
【分類號】：P184.1
【正文快照】： 1月海玄武巖的基本特征、分布和年代學(xué)1.1分布特征0引言美國于1969-1972年間實(shí)施的Apollo探月計劃是人類對月球及其演化的認(rèn)識的轉(zhuǎn)折點(diǎn)。其中最重要的原因是美國6次Apollo載人探月計劃和俄羅斯3次非載人計劃向地球返回了近地球一側(cè)9個點(diǎn)的380kg月球樣品(Apollo11、12、15、17

【共引文獻(xiàn)】

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1 李雯;崔q，

本文編號：1339043