High-pressure minerals in the eucrite Padvarninkai were investigated. Parts of anorthitic plagioclase and tridymite in the host rock of Padvarninkai vitrified, indicating that the shock pressure was 22–27 GPa. Tissintite, coesite, and a majorite-bearing garnet occurred in the shock-melt veins of Padvarninkai as high-pressure minerals. Tissintite, kyanite, corundum, and dense plagioclase have occurred in the anorthitic plagioclase grains. The anorthitic plagioclase was melted and tissintite crystallized from the melt after the crystallization of kyanite and corundum. The residual melt became dense plagioclase by quenching. Tridymite has also melted and coesite crystallized from the melt. The formation of tissintite and coesite indicates that the shock pressure recorded in the veins was 2–13 GPa. The temperature increased drastically in the veins (>˜3000 K) compared with the host rock (<˜800 K). Parts of the tissintite and coesite became, respectively, amorphous (or anorthite) and quartz. Two different impact events may be recorded in Padvarninkai: The first impact event brecciated a part of the host rock, and the second impact event induced the melting of the brecciated portion, resulting in the formation of shock-melt veins where the conditions are a high temperature and a relatively low pressure. In the veins, tissintite and coesite formed first, and parts of them underwent a back-transformation due to a long cooling time.

中文翻译：

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在 Padvarninkai 中记录的复杂压力-温度路径

研究了 Padvarninkai 中的高压矿物。Padvarninkai 主岩中部分斜长石斜长石和鳞石英玻璃化，表明冲击压力为 22-27 GPa。Tissintite、柯石英和一种含主要矿物的石榴石作为高压矿物出现在 Padvarninkai 的冲击熔岩脉中。斜长石斜长石颗粒中出现了钛青石、蓝晶石、刚玉和致密斜长石。在蓝晶石和刚玉结晶后，斜长石被熔化并从熔体中结晶出组织长石。残余熔体通过淬火变成致密的斜长石。鳞石英也熔化了，柯石英从熔体中结晶出来。tissintite 和柯石英的形成表明脉中记录的冲击压力为 2-13 GPa。与主岩 (<~800 K) 相比，矿脉中的温度 (>~3000 K) 急剧增加。部分tissintite和柯石英分别变成了无定形（或钙长石）和石英。Padvarninkai 可能记录了两种不同的撞击事件：第一次撞击事件形成了一部分主岩，第二次撞击事件引发了角砾岩部分的熔化，导致在条件高的地方形成了冲击熔岩脉。温度和相对较低的压力。在矿脉中，首先形成了铁青石和柯石英，部分由于冷却时间长而发生了逆变。第一次撞击使部分主岩形成角砾岩，第二次撞击引起角砾岩部分熔融，形成了高温、低压条件下的冲击熔岩脉。在矿脉中，首先形成了铁青石和柯石英，部分由于冷却时间长而发生了逆变。第一次撞击使部分主岩形成角砾岩，第二次撞击引起角砾岩部分熔融，形成了高温、低压条件下的冲击熔岩脉。在矿脉中，首先形成了铁青石和柯石英，部分由于冷却时间长而发生了逆变。