| 南极陨石研究的启示Ⅳ．南极陨石热释光研究 |
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| 引用本文： | 陈永亨,王道德.南极陨石研究的启示Ⅳ．南极陨石热释光研究[J].极地研究,1994,6(2):16-34. |
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| 作者姓名： | 陈永亨 王道德 |
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| 作者单位： | 中国科学院广州地质新技术研究所 |
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| 基金项目： | 中国科学院“八五”重大基础资助 |
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| 摘 要： | 陨石热释光研究揭示了陨石中自然ＴＬ值取决于陨石暴露在宇宙空间时的宇宙射线辐照和自身热衰变之间的平衡。宇宙剂量率（决定于初始屏蔽作用）和反照率直接影响陨石的自然ＴＬ值。相对于非南极陨石，南极陨石由于大的地球年龄而具有更低的自然ＴＬ值。一些具有特别低自然ＴＬ值的陨石（～１５％）表明经历了近期的加热作用，它们可能以特别小的近日距（＜０．８ＡＵ）轨道到达地球上。普通球粒陨石的ＴＬ灵敏度反映了长石的性质和丰度，冲击加热不仅降低陨石的自然ＴＬ值，而且破坏ＴＬ发光体，导致ＴＬ灵敏度下降。变质作用通过原始火成玻璃的脱玻作用产生长石，使普通球粒陨石的ＴＬ灵敏度增加达１０５倍。因此，ＴＬ灵敏度的测定已用作３型普通球粒陨石，ＣＯ、ＣＶ球粒陨石和钙长辉长无球粒陨石新的分类方法。诱导ＴＬ曲线的峰温和峰宽也与陨石的热历史有关。相对于ＴＬ发光体长石的无序化，它们随着变质作用的增加而增高，使得这些参数可以用来估计变质平衡温度。新的陨石ＴＬ数据已经用于讨论来自火星的Ｓｈｅｒｇｏｔｉｔｅｓ陨石的溅射、地－月转换时间、南极陨石风化作用和可能的地外来源。
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| 关 键 词： | 南极 陨石 热释光 热历史 陨石演化 |
INSPIRATION FROM STUDY OF ANTARCTIC METEORITES Ⅳ. THERMOLUMINESCENCE STUDIES OF ANTARCTIC METEORITES |
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| Chen Yongheng.INSPIRATION FROM STUDY OF ANTARCTIC METEORITES Ⅳ. THERMOLUMINESCENCE STUDIES OF ANTARCTIC METEORITES[J].Chinese Journal of Polar Research,1994,6(2):16-34. |
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| Authors: | Chen Yongheng |
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| Abstract: | Thermoluminescence studies of meteorites suggest that the level of natural TL in meteorites is determined by competition between build up,due to exposure to cosmic radiation,and thermal decay.The cosmic dose rate (determined primarily by shielding) and albedo directly affect the level of natural TL in meteorites.Relative to non Antarctic meteorites,Antarctic meteorites have lower level of natural TL due to their large terrestrial ages.Some meteorites ( ～15%) have especially low natural TL,suggesting that they have recently been reheated.These may have come to earth on orbits with particularly small perihelion (<0.8 AU).The TL sensitivity of ordinary chondrites reflects the abundance and nature of feldspar.Shock heating not only decreases the level of natural TL in meteorites,but also destroys the TL phosphor resulting in a decrease in the TL sensitivity of meteorites. Metamorphism generates feldspar through the devitrification of primary igneous glass and causes TL sensitivity to increase by a factor of ～10 5 in ordinary chondrites.The measurement of TL sensitivity has produced new means of classification for 3 type of ordinary chondrites,CO,CV chondrites and eucrites.The peak temperature and peak width of the induced TL curve are also related with the thermal history of meteorites. Relative to disordering of feldspar-which is the TL phosphor, they increase with increasing metamorphism so that these parameters can be used to obtain an estimate of the metamorphic equilibration temperatures. New TL research data of meteorites have been used to discuss the ejection of the shergottites from Mars and earth moon transit times,weathering of Antarctic meteorites and possible differences in extraterrestrial sources. |
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| Keywords: | s Antarctica meteorites thermoluminescence thermal history evolution of meteorites |
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