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Chronology of Fresh Rayed Craters in Elysium Planitia, Mars
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hundal, Carol B. Golombek, Matthew P. Daubar, Ingrid J. |
| Copyright Year | 2017 |
| Abstract | Introduction: While fresh impact craters are easily recognized by their high-albedo rays on the Moon and Mercury, fresh rayed craters on Mars have only been identified recently in thermal infrared images [1]. These rays are believed to be among the youngest geomorphic features on Mars; closer inspection of them reveals high densities of secondary impact craters [2]. Elysium Planitia has the largest concentration of identified rayed craters on Mars, and their thermal rays overlap one other in a number of regions, including the landing site for the InSight mission [3]. Similar to [4], we use superpositions of secondary craters as seen in High Resolution Imaging Science Experiment (HiRISE) images to determine relative ages among seven fresh rayed craters between 1.5 and 13.9 km in diameter (Fig 1). We further constrain these ages with crater-counting age estimates of their continuous ejecta blankets, calculated recurrence intervals, and previous estimates of the ages of these craters from the literature. Secondary Superpositions: Populations of secondary craters from a particular primary tend to exhibit a common set of morphological attributes, particularly at the same distance from the primary. Using methods described in [5], attributes such as typical diameter and distinctive ejecta were noted for each secondary population. Where both populations were present, we used these attributes to determine source craters and thus superposition relationships. Recurrence intervals: Recurrence intervals are an estimate of the average amount of time between successive impacts of a given size, over a given area [6]. The intervals in this study are based on the Neukum et al. 2001 production function [7]. Recurrence intervals (Fig. 2) are given for 30%, 50%, and 100% of Mars’ surface for three reasons. First, most of the rayed craters are found in the equatorial region in global moderate to high thermal inertia and high albedo Unit C [6]; this unit covers ~30% of Mars. Second, ~50% of Mars is within 30° of the equator where fresh rayed craters have been found [2]. Finally, recurrence intervals are often calculated over 100% of Mars’ area, so those are also included for comparison with the literature, although they are not as relevant in this case. Crater counts: Crater counts were performed on craters that had superposition relationships with sec- |
| Starting Page | 1726 |
| Ending Page | 1726 |
| Page Count | 1 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.hou.usra.edu/meetings/lpsc2017/pdf/1726.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
