Noble gases and halogens in Graves Nunataks 06129: The complex thermal history of a felsic asteroid crust
Noble gases and halogens in Graves Nunataks 06129: The complex thermal history of a felsic asteroid crust
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格雷夫斯努纳塔克斯 06129 中的稀有气体和卤素：长英质小行星地壳的复杂热历史
DOI：
10.1016/j.gca.2015.03.013
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发表时间：
2015
影响因子：
5
通讯作者：
Claydon J
中科院分区：
文献类型：
--
作者：
Claydon J
格雷夫斯冰原岛峰06128/06129陨石是长英质小行星地壳的罕见例子。了解它的历史有助于了解星子的演化过程。稀有气体可用于限制陨石的年代学和导致小行星体上挥发性元素运动的过程。利用高分辨率激光分步加热辐照样品，研究了格雷夫斯冰原岛峰06129富斜长石无球粒陨石的I-Ar和Ar-Ar系统。碘和129氚都存在，但在不同温度下释放，没有显示出相关性，因此GRA 06129中的I-氚系统没有年代学意义。我们建议，radiogenic 129氚失去了从初级阶段和parentless 129氚后来被引入到岩石中的相互作用，从一个水库，演变成一个高的I/I比值的流体来源。这可能与诱导镁橄榄石和辉石转化为氯磷灰石的富含卤素的流体相同。继承的40 Ar（即不是由40 K的原位衰变产生的）也存在于这里研究的三个碎片之一中，并且可能与无母体的129 Ar同时引入。
The meteorite Graves Nunataks 06128/06129 is a rare example of felsic asteroidal crust. Knowledge of its history can help shed light on the evolution processes of planetesimals. The noble gases can be used to constrain both the chronology of meteorites and the processes that result in movements of volatile elements on asteroidal bodies. We have examined the I–Xe and Ar–Ar systems of the plagioclase-rich achondrite, Graves Nunataks 06129 by high-resolution laser step-heating of irradiated samples. Iodine and129Xe∗are both present but are released at different temperatures and do not show a correlation, therefore the I–Xe system in GRA 06129 has no chronological significance. We propose that radiogenic129Xe∗was lost from primary phases and parentless129Xe∗was later introduced into the rock by interaction with a fluid sourced from a reservoir that evolved with a high I/Xe ratio. This could have been the same halogen-rich fluid that induced the conversion of merrillite and pyroxene into chlorapatite. Inherited40Ar (i.e. not generated byin situdecay of40K) is also present in one of three fragments studied here and may have been introduced at the same time as parentless129Xe∗.