Formation of shatter cones in MEMIN impact experiments
Formation of shatter cones in MEMIN impact experiments
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MEMIN 冲击实验中破碎锥的形成
DOI：
10.1111/maps.12682
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发表时间：
2016
影响因子：
2.2
通讯作者：
Kenkmann T.
中科院分区：
文献类型：
--
作者：
Wilk J.;Kenkmann T.
破碎锥是被认为是冲击变质作用证据的唯一宏观特征。它们的存在对于发现和验证撞击结构具有诊断意义。在整个陨石坑记录中，破碎锥的出现是不均匀的，它们的几何形状可能与典型的圆锥形状不同。破碎锥的形成机理至今尚未完全阐明。在这项研究中，我们的目标是更好地约束碰撞实验中的破碎锥形成的边界条件，并测试一种新的方法来定性和定量地描述破碎锥的几何形状的白色光干涉。我们从MEMIN陨石坑实验中回收了几个喷射碎片，这些碎片显示出轻微弯曲的条纹状表面和顶点为36°-52°的圆锥形几何形状。这些碎片满足粉碎锥的形态标准，发现在实验中与20-80厘米大小的目标立方体的砂岩，石英岩和石灰岩，但不是在高度多孔凝灰岩。目标被铝、钢和铁陨石以4.6-7.8 km s-1的速度撞击。抛射体直径范围为2.5-12 mm，产生的实验峰值压力高达86 GPa。在较低的冲击速度的实验中，破碎锥不能被发现。一个彻底的形态学分析的实验产生的破碎锥进行了三维白色光干涉扫描在微米精度。回收的碎片的表面的SEM分析表明，泡状熔融膜交替与光滑的抛光表面。我们推测，泡状熔体膜主要形成在应变释放步骤，并建议破碎锥可能是混合模式骨折。
Shatter cones are the only macroscopic feature considered as evidence for shock metamorphism. Their presence is diagnostic for the discovery and verification of impact structures. The occurrence of shatter cones is heterogeneous throughout the crater record and their geometry can diverge from the typical cone shape. The precise formation mechanism of shatter cones is still not resolved. In this study, we aim at better constraining the boundary conditions of shatter cone formation in impact experiments and test a novel approach to qualitatively and quantitatively describe shatter cone geometries by white light interferometry. We recovered several ejected fragments from MEMIN cratering experiments that show slightly curved, striated surfaces and conical geometries with apices of 36°–52°. These fragments fulfilling the morphological criteria of shatter cones were found in experiments with 20–80 cm sized target cubes of sandstone, quartzite and limestone, but not in highly porous tuff. Targets were impacted by aluminum, steel, and iron meteorite projectiles at velocities of 4.6–7.8 km s−1. The projectile sizes ranged from 2.5–12 mm in diameter and produced experimental peak pressures of up to 86 GPa. In experiments with lower impact velocities shatter cones could not be found. A thorough morphometric analysis of the experimentally generated shatter cones was made with 3D white light interferometry scans at micrometer accuracy. SEM analysis of the surfaces of recovered fragments showed vesicular melt films alternating with smoothly polished surfaces. We hypothesize that the vesicular melt films predominantly form at strain releasing steps and suggest that shatter cones are probably mixed mode fractures.
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影响因子：
5.3
作者：
A. Kowitz;N. Güldemeister;W. Reimold;R. Schmitt;K. Wünnemann
通讯作者：
A. Kowitz;N. Güldemeister;W. Reimold;R. Schmitt;K. Wünnemann
影响因子：
2.2
作者：
Cintala, MJ;Berthoud, L;Hörz, F
通讯作者：
Hörz, F
重新审视 Vredefort 破碎锥
影响因子：
--
作者：
L. Nicolaysen;W. Reimold
通讯作者：
W. Reimold
影响因子：
56.9
作者：
N. Gay
通讯作者：
N. Gay
首次在低冲击压力 (5–12.5 GPa) 下使用干燥多孔砂岩进行 MEMIN 冲击恢复实验
影响因子：
2.2
作者：
A. Kowitz;R. Schmitt;W. Uwe Reimold;U. Hornemann
通讯作者：
U. Hornemann