Quartz and cristobalite ballen aggregates surrounded by dendritic cristobalite in gneiss clasts of impact melt rocks from the Ries impact structure are analyzed by Raman spectroscopy, microscopy, and electron backscattered diffraction to elucidate the development of the characteristic polycrystalline ballen that are defined by curved interfaces between each other. We suggest that the investigated ballen aggregates represent former fluid inclusion‐rich quartz grains from the granitic gneiss protolith. Upon shock loading, they transformed into an amorphous phase that partly retained information on the precursor structure. Volatiles from inclusions dissolved into the amorphous phase. During decompression and cooling, dehydration takes place and causes fracturing of the amorphous phase and disintegration into small globular ballen, with the fluid being expelled along the fractures. A similar formation of small globules due to dehydration of silica‐rich glass is known for perlitic structures of volcanic rocks. Remnants of the precursor structure are present in the amorphous phase and enabled topotactic crystallization of quartz, leading to a crystallographic preferred orientation. Crystallization of more distorted parts of the amorphous phase led to random orientations of the quartz crystals. Ballen comprised of cristobalite formed from a dehydrated amorphous phase with no structural memory of the precursor. Dendritic cristobalite exclusively occurring at the rim of quartz ballen aggregate is interpreted to have crystallized directly from a melt enriched in fluids that were expelled during dehydration of the amorphous phase.

中文翻译：

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冲击产生的非晶态相脱水形成的德国Ries冲击结构中的冲击熔岩中的石英和方石英球

通过拉曼光谱，显微镜和电子背散射衍射分析了来自Ries撞击结构的撞击熔岩的片麻岩片岩中被树枝状方石英包围的石英和方石英球状聚集体，从而阐明了特征性多晶球形物的发展，该球形物由各自之间的弯曲界面定义其他。我们建议所研究的球状骨料代表来自花岗岩片麻岩原石的富集流体包裹体的石英颗粒。受到冲击载荷后，它们转变为非晶相，从而部分保留了前体结构上的信息。夹杂物的挥发物溶解到非晶相中。在减压和冷却过程中，会发生脱水并导致非晶相破裂并崩解成小球状ball 沿裂缝驱出的流体。火山岩的珍珠岩结构也因富含二氧化硅的玻璃脱水而形成类似的小球状结构。前体结构的残余物存在于无定形相中，并且能够使石英进行晶化结晶，从而导致晶体学优选取向。非晶相的更多变形部分的结晶导致石英晶体的随机取向。由无定形脱水相形成的方石英组成的巴伦，没有前体的结构记忆。完全存在于石英球状骨料边缘的树枝状方石英被解释为直接从富含非晶态相脱水过程中排出的流体的熔体中结晶。火山岩的珍珠岩结构也因富含二氧化硅的玻璃脱水而形成类似的小球状结构。前体结构的残余物存在于无定形相中，并且能够使石英进行晶化结晶，从而导致晶体学优选取向。非晶相中更扭曲的部分的结晶导致石英晶体的随机取向。由无定形脱水相形成的方石英组成的巴伦，没有前体的结构记忆。完全存在于石英球状骨料边缘的树枝状方石英被解释为直接从富含非晶态相脱水过程中排出的流体的熔体中结晶。火山岩的珍珠岩结构也因富含二氧化硅的玻璃脱水而形成类似的小球状结构。前体结构的残余物存在于无定形相中，并且能够实现石英的晶化结晶，从而导致晶体学优选取向。非晶相中更扭曲的部分的结晶导致石英晶体的随机取向。由无定形脱水相形成的方石英组成的巴伦，没有前体的结构记忆。完全存在于石英球状骨料边缘的树枝状方石英被解释为直接从富含非晶态相脱水过程中排出的流体的熔体中结晶。