Prior to becoming chondritic meteorites, primordial solids were a poorly consolidated mix of mm-scale igneous inclusions (chondrules) and high-porosity sub-μm dust (matrix). We used high-resolution numerical simulations to track the effect of impact-induced compaction on these materials. Here we show that impact velocities as low as 1.5 km s−1 were capable of heating the matrix to >1,000 K, with pressure–temperature varying by >10 GPa and >1,000 K over ~100 μm. Chondrules were unaffected, acting as heat-sinks: matrix temperature excursions were brief. As impact-induced compaction was a primary and ubiquitous process, our new understanding of its effects requires that key aspects of the chondrite record be re-evaluated: palaeomagnetism, petrography and variability in shock level across meteorite groups. Our data suggest a lithification mechanism for meteorites, and provide a ‘speed limit’ constraint on major compressive impacts that is inconsistent with recent models of solar system orbital architecture that require an early, rapid phase of main-belt collisional evolution.
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机译：在变成粒状陨石之前，原始固体是毫米级火成夹杂物（软骨）和高孔隙度亚微米粉尘（基质）的不良结合体。我们使用高分辨率的数值模拟来跟踪冲击致密化对这些材料的影响。在这里，我们显示出低至1.5 km s -1 的撞击速度能够将基体加热到> 1,000 K，压力-温度在〜100μm范围内变化> 10 GPa和> 1,000K。软骨不受影响，起着散热器的作用：基质温度波动很短。由于撞击引起的压实是一个普遍存在的主要过程，因此，我们对球撞击的作用的新认识要求重新评估球粒陨石记录的关键方面：古磁性，岩石学和陨石群体的震级变化。我们的数据提出了陨石的石化机制，并为主要压缩冲击提供了“速度限制”约束，这与最近的太阳系轨道结构模型（需要早期，快速的主带碰撞演化）不一致。
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