Ganymede crater dimensions - Implications for central peak and central pit formation and development
Ganymede crater dimensions - Implications for central peak and central pit formation and development
复制标题
DOI：
10.1016/j.icarus.2011.10.004
复制
发表时间：
2012-01-01
期刊：
影响因子：
3.2
通讯作者：
Collins, Gareth S.
中科院分区：
文献类型：
--
作者：
Bray, Veronica J.;Schenk, Paul M.;Collins, Gareth S.
冰冷的伽利略卫星上的撞击坑的形态与岩石体上的撞击坑不同。这些差异被认为是由于冰的相对脆弱性和可能存在的地下水层。根据伽利略图像建立的数字高程模型被用来测量木卫三黑暗和明亮地形上陨石坑的一系列尺寸。对每个陨石坑的多个剖面进行了测量，以便评估陨石坑尺寸的自然变化，并构建平均比例趋势。这项工作中报告的额外深度、坡度和体积信息使人们能够研究中央峰的形成和发展，并对中央坑形成的各种理论进行定量评估。我们注意到一个可能的差异，在大小形态的进展之间的小陨石坑的冰和硅酸盐机构，其中中央峰出现在小陨石坑之前，有任何塌陷的陨石坑边缘，这是相反的观察到的序列在月球上。相反，我们的陨石坑尺寸分析表明，大型月球陨石坑从中央峰到峰环的尺寸形态进展反映在木卫三上，但峰环随后被修改为中央坑形态。坑的形成可能是由于表面材料塌陷到撞击引起的挥发物逐渐释放留下的空隙中，或撞击熔化物排入亚坑裂缝中。(C)2011 Elsevier Inc. All rights reserved.
The morphology of impact craters on the icy Galilean satellites differs from craters on rocky bodies.. The differences are thought due to the relative weakness of ice and the possible presence of sub-surface water layers. Digital elevation models constructed from Galileo images were used to measure a range of dimensions of craters on the dark and bright terrains of Ganymede. Measurements were made from multiple profiles across each crater, so that natural variation in crater dimensions could be assessed and averaged scaling trends constructed. The additional depth, slope and volume information reported in this work has enabled study of central peak formation and development, and allowed a quantitative assessment of the various theories for central pit formation. We note a possible difference in the size-morphology progression between small craters on icy and silicate bodies, where central peaks occur in small craters before there is any slumping of the crater rim, which is the opposite to the observed sequence on the Moon. Conversely, our crater dimension analyses suggest that the size-morphology progression of large lunar craters from central peak to peak-ring is mirrored on Ganymede, but that the peak-ring is subsequently modified to a central pit morphology. Pit formation may occur via the collapse of surface material into a void left by the gradual release of impact-induced volatiles or the drainage of impact melt into sub-crater fractures. (C) 2011 Elsevier Inc. All rights reserved.