Microscopic impactor debris in the soil around Kamil crater (Egypt): Inventory,distribution, total mass,and implications for the impact scenario |
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| Authors: | Luigi Folco Massimo D'Orazio Agnese Fazio Carole Cordier Antonio Zeoli Matthias van Ginneken Ahmed El‐Barkooky |
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| Institution: | 1. Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy;2. Université de Grenoble Alpes, Grenoble, CEDEX 9, France;3. CNRS, Istitute des Sciences de la Terre (ISTerre), Grenoble, CEDEX 9, France;4. Museo Nazionale dell'Antartide, Università di Siena, Siena, Italy;5. Department of Earth Science and Engineering, Imperial College, London, UK;6. Department of Geology, Faculty of Sciences, Cairo University, Giza, Egypt |
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| Abstract: | We report on the microscopic impactor debris around Kamil crater (45 m in diameter, Egypt) collected during our 2010 geophysical expedition. The hypervelocity impact of Gebel Kamil (Ni‐rich ataxite) on a sandstone target produced a downrange ejecta curtain of microscopic impactor debris due SE–SW of the crater (extending ~300,000 m2, up to ~400 m from the crater), in agreement with previous determination of the impactor trajectory. The microscopic impactor debris include vesicular masses, spherules, and coatings of dark impact melt glass which is a mixture of impactor and target materials (Si‐, Fe‐, and Al‐rich glass), plus Fe‐Ni oxide spherules and mini shrapnel, documenting that these products can be found in craters as small as few tens of meters in diameter. The estimated mass of the microscopic impactor debris (<290 kg) derived from Ni concentrations in the soil is a small fraction of the total impactor mass (~10 t) in the form of macroscopic shrapnel. That Kamil crater was generated by a relatively small impactor is consistent with literature estimates of its pre‐atmospheric mass (>20 t, likely 50–60 t). |
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