Eutectic metal plus troilite plus Fe-Mn-Na phosphate plus Al-free chromite assemblage in shock-produced chondritic melt of the Yanzhuang chondrite
Eutectic metal plus troilite plus Fe-Mn-Na phosphate plus Al-free chromite assemblage in shock-produced chondritic melt of the Yanzhuang chondrite
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燕庄球粒陨石冲击生成球粒熔体中的共晶金属+陨铁石+磷酸铁锰钠+无铝铬铁矿组合
DOI：
10.1111/maps.12379
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发表时间：
2014
影响因子：
2.2
通讯作者：
Wang Fuya
中科院分区：
文献类型：
--
作者：
Xie Xi;e;Chen Ming;Zhai Shuangmeng;Wang Fuya
在燕庄H6陨石激波产生的球粒熔体中，鉴定出镍金属、三亚硝石、磷酸铁锰钠和无铝铬铁矿的共晶结核组合。电子探针和拉曼光谱分析表明，少数磷酸盐球具有含钠接枝石（Fe,Mn,Na）3(PO4)2的组成，而大多数磷酸盐球对应于含锰伽利略石Na(Fe,Mn)4(PO4)3和可能的新磷酸盐相Na2(Fe,Mn)17(PO4)12的组成。岩庄陨石被震至峰值压力50 GPa，峰值温度约2000℃。所有的矿物质都在压力释放后融化，形成球粒陨石融化，这是由于非常高的冲击后热量将球粒陨石物质带到了液体之上。铁长石和斜长石释放的挥发性元素P和Na以及铬铁矿释放的Cr和Mn在高温下被集中到冲击产生的Fe - Ni - S - O熔体中。在冷却过程中，微晶橄榄石和辉石首先从球粒体熔体结晶，金属-三硅石共晶共生，硅酸盐熔融玻璃最终在950-1000℃凝固。另一方面，Fe - Ni - S - O中的P、Mn和Na与Fe结合，在三苯胺中结晶为Fe - Mn - Na磷酸盐，而Cr与Fe结合，在三苯胺中结晶为无Al铬铁矿。
An assemblage with FeNi metal, troilite, Fe‐Mn‐Na phosphate, and Al‐free chromite was identified in the metal‐troilite eutectic nodules in the shock‐produced chondritic melt of the Yanzhuang H6 meteorite. Electron microprobe and Raman spectroscopic analyses show that a few phosphate globules have the composition of Na‐bearing graftonite (Fe,Mn,Na)3(PO4)2, whereas most others correspond to Mn‐bearing galileiite Na(Fe,Mn)4(PO4)3and a possible new phosphate phase of Na2(Fe,Mn)17(PO4)12composition. The Yanzhuang meteorite was shocked to a peak pressure of 50 GPa and a peak temperature of approximately 2000 °C. All minerals were melted after pressure release to form a chondritic melt due to very high postshock heat that brought the chondrite material above its liquidus. The volatile elements P and Na released from whitlockite and plagioclase along with elements Cr and Mn released from chromite are concentrated into the shock‐produced Fe‐Ni‐S‐O melt at high temperatures. During cooling, microcrystalline olivine and pyroxene first crystallized from the chondritic melt, metal‐troilite eutectic intergrowths, and silicate melt glass finally solidified at about 950–1000 °C. On the other hand, P, Mn, and Na in the Fe‐Ni‐S‐O melt combined with Fe and crystallized as Fe‐Mn‐Na phosphates within troilite, while Cr combined with Fe and crystallized as Al‐free chromite also within troilite.