Oldest high-Ti basalt and magnesian crustal materials in feldspathic lunar meteorite Dhofar 1428
Oldest high-Ti basalt and magnesian crustal materials in feldspathic lunar meteorite Dhofar 1428
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长石月球陨石 Dhofar 1428 中最古老的高钛玄武岩和镁质地壳材料
DOI：
10.1016/j.gca.2019.06.022
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发表时间：
2019-06
影响因子：
5
通讯作者：
Xu Yigang
中科院分区：
文献类型：
--
作者：
Xue Zhuqing;Xiao Long;Neal Clive R.;Xu Yigang
为了更好地了解月球地壳的组成和演化，我们对Dhofar 1428号陨石进行了彻底的分析。该样品包括一系列不均匀的岩屑，包括镁质和铁质斜长麻粒岩、镁铁质麻粒岩/麻粒角砾岩、玄武岩和不同种类的冲击熔融岩。其中，高钛玄武岩碎屑包括大的带状辉石观察。基于平衡熔体计算的矿物分带从这个玄武岩，镁辉石核心被解释为形成从轻稀土元素（LREE）富集的液体，而铁辉石边缘生长从LREE亏损的岩浆。我们建议，轻稀土贫化签名的铁辉石的结果与磷灰石共结晶。镁辉石表明，月球内部存在稀土元素含量较高的富集液，其稀土元素模式与KREEP不同。振荡的Ti/Al比值在辉石在这个玄武岩可能表明几个岩浆补给事件或晶体运动内分区岩浆房。这一特征表明，岩浆来自不同的来源周围的时间形成的玄武岩。对该玄武岩中磷灰石颗粒进行了原位U-Pb测年，（3941 ± 24 Ma，2σ）和207 Pb/206 Pb等时线年龄（3934 ± 24 Ma，2σ）表明该高钛玄武岩最可能的结晶年龄为3.94亿年，镁斜长麻粒岩在矿物学和地球化学上与许多月球陨石中贫微量元素的镁斜长麻粒岩相似。这些镁质麻粒岩不能由原始的含铁斜长岩和镁套岩石的简单混合形成，并且与KREEP或Procellarum KREEP地体没有任何亲缘关系，它们可能是远侧高地的重要组成部分。
We conducted a thorough analysis of the feldspathic breccia meteorite Dhofar 1428 with the aim of better understanding the composition and evolution of lunar crust. This sample comprises a heterogeneous array of lithic fragments including magnesian and ferroan anorthositic granulites, mafic granulites/granulitic breccia, basalts, and different kinds of impact melt rocks. In which, a high-Ti basalt clast comprising large zoned pyroxene was observed. Based on equilibrium melt calculations of mineral zonations from this basalt, Mg-pyroxene cores were interpreted to be formed from a light rare earth element (LREE) enriched liquid, whereas the Fe-pyroxene rims grew from an LREE-depleted magma. We propose that LREE-depleted signature of Fe-pyroxene results from co-crystallization with apatite. The Mg-pyroxenes suggest that enriched liquids with higher REE contents and different REE patterns relative to KREEP existed within lunar interior. Oscillating Ti/Al ratios across pyroxene in this basalt may indicate several magma recharge events or crystal movement within a zoned magma chamber. This feature illustrates that magmas were derived from a variety of sources around the time of formation of this basalt. In situ U-Pb dating was conducted on apatite grains within this basalt, the excellent consistence between the U-Pb Concordia age (3941 ± 24 Ma, 2σ) and207Pb/206Pb isochron age (3934 ± 24 Ma, 2σ) indicates the most likely crystallization age of this high-Ti basalt at ∼3940 Myr, making it one of the oldest high-Ti basalts formed on the Moon.Magnesian anorthositic granulites are mineralogically and geochemically similar to those trace element-poor magnesian anorthositic granulites in many lunar meteorites. These magnesian granulites cannot form from simple mixing of pristine Ferroan Anorthosite and lithologies from the Mg-Suite, and do not have any affinities with KREEP or the Procellarum KREEP Terrane, and they could be important components of farside highlands.
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影响因子：
5
作者：
F. McCubbin;B. Jolliff;H. Nekvasil;P. K. Carpenter;R. Zeigler;A. Steele;S. Elardo;D. Lindsley
通讯作者：
F. McCubbin;B. Jolliff;H. Nekvasil;P. K. Carpenter;R. Zeigler;A. Steele;S. Elardo;D. Lindsley
DOI：
--
发表时间：
2008-03
期刊：
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影响因子：
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影响因子：
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作者：
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DOI：
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发表时间：
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期刊：
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影响因子：
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作者：
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通讯作者：
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DOI：
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发表时间：
1972
期刊：
--
影响因子：
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作者：
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