Timing of the faulting on the Wispy Terrain of Dione based on stratigraphic relationships with impact craters
Timing of the faulting on the Wispy Terrain of Dione based on stratigraphic relationships with impact craters
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基于与撞击坑的地层关系确定 Dione 的 Wispy Terrain 断层的时间
DOI：
10.1002/2016je005176
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Naoyuki Hirata
中科院分区：
文献类型：
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作者：
Naoyuki Hirata;Naoyuki Hirata
土卫六尾随半球的特点是“纤细地形”，它展示了叠加在月球陨石坑表面上的半球规模的伸展构造断层网络。这些断层可能反映了过去的内生活动和狄俄涅内部的热历史。尽管原始悬崖的新暴露表明断层的发生时间相对较新，但断层的绝对年龄仍然不确定。为了估计断层发生的时间，我们研究了撞击坑和断层之间的地层关系。利用卡西尼号飞船上的国际空间站相机获得的高分辨率图像，我们研究了与断层空间重合的直径超过或等于10公里的陨石坑，并将这些陨石坑分类为横切陨石坑或叠加陨石坑。结果，至少 82% 的陨石坑被解释为横切陨石坑的明显例子，12% 的陨石坑被解释为重叠陨石坑的候选者，尽管地层关系通常是模糊的。重叠陨石坑的数量和预测的陨石坑发生率表明，Wispy Terrain 的断层活动为 0.30–0.79 Ga。如果假设 12–18% 的陨石坑是重叠的，则断层活动的时间可能在 0.30–0.79 Ga 范围内。然而，Wispy Terrain 的断层活动可能仍在持续。
The trailing hemisphere of Dione is characterized by the Wispy Terrain, where it exhibits a hemispheric‐scale network of extensional tectonic faults superposed on the moon's cratered surface. The faults likely reflect past endogenic activity and Dione's interior thermal history. Although fresh exposures of pristine scarps indicate that the timing of the faulting is relatively recent, the absolute age of the faulting remains uncertain. To estimate the timing of the faulting, we investigated stratigraphic relationships between impact craters and faults. Using high‐resolution images obtained by the ISS camera onboard the Cassini spacecraft, we investigated craters with diameters exceeding or equal to 10 km that coincide spatially with the faults and classified the craters as crosscut craters or superposed craters. As a result, at least 82% of the craters were interpreted as clear examples of crosscut craters and 12% of the craters were interpreted to be candidates of superposed craters, although stratigraphic relationships are often ambiguous. The paucity of superposed craters and a predicted cratering rate indicate that the faulting of the Wispy Terrain is 0.30–0.79 Ga. If 12–18% of the craters are assumed to be superposed, the timing of the faulting could be in the range 0.30–0.79 Ga. However, it is possible that the faulting of the Wispy Terrain is still ongoing.