The Bovedy meteorite; mineral chemistry and origin of its Ca-rich glass inclusions
The Bovedy meteorite; mineral chemistry and origin of its Ca-rich glass inclusions
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博维迪陨石；
DOI：
10.1016/0016-7037(76)90220-9
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发表时间：
1976
影响因子：
5
通讯作者：
D. Jérôme
中科院分区：
文献类型：
--
作者：
A. Graham;A. J. Easton;R. Hutchison;D. Jérôme
博韦迪陨石于1969年4月25日坠落在北方爱尔兰，主要质量为4.94公斤，位于博韦迪（北纬54°57′，西经06°37′）。它是一个L3球粒陨石，有丰富的球粒，在手标本中清晰可见。大量的化学分析，总铁含量为22.5%。橄榄石是均匀的（Fa 24），但辉石不是平衡的（Fs 8 -28）。棕色玻璃在陨石球粒中很常见，但在少数富含斜方辉石（Fs 17 -28）的陨石球粒中也有成分为An 85的透明玻璃。在陨石的一块石头中发现了一个直径为2毫米的透明玻璃泡，成分为An 85，并在玻璃中测定了五种稀土元素（La，Sm，Eu，Yb，Lu）。低稀土元素丰度加上一个大的正铕异常斜长石的特点，但更精细的细节的图案表明，这种玻璃有一个更密切的亲和力，月球斜长岩比斜长石月海玄武岩或eucritic陨石。也有证据表明，来自地球外来源的斜长石和斜长岩的Eu异常的幅度与三价稀土元素含量呈负相关。斜长岩材料的存在，并因此，分化的行星体形成之前的Bovedy陨石的建议。
The Bovedy meteorite fell on 25 April 1969 in Northern Ireland; the main mass of 4·94 kg was found at Bovedy (54°57′N, 06°37′W). It is an L3 chondrite with abundant chondrules clearly visible in hand specimen. Bulk chemical analyses are presented, the total Fe content being 22·5%. The olivines are homogeneous (Fa24) but the pyroxenes are not equilibrated (Fs8–28). Brown glass is common within chondrules but a clear glass of composition An85is present interstitially in a few orthopyroxene-rich (Fs17–28) chondrules. A bleb, 2 mm across, of clear glass, again of composition An85was found in one stone of the meteorite and in the glass five REE (rare earth elements), (La, Sm, Eu, Yb, Lu) were determined. The low REE abundances coupled with a large positive Eu anomaly are characteristic of plagioclase, but the finer details of the pattern suggest that this glass has a closer affinity to the lunar anorthosites than to plagioclases from lunar mare basalts or eucritic meteorites. There is also evidence that the magnitude of the Eu anomaly for plagioclases and anorthosites from extra-terrestrial sources is inversely related to trivalent REE content. The existence of anorthositic material and, as a consequence, a differentiated planetary body prior to the formation of the Bovedy meteorite is suggested.