1. Robbins S. J. and Hynek B. M. (2012). J. Geophys. Res., 117, E05004, doi: 10.1029/2011JE0039662. Lowell Crater. (2018, May 25). 3. Retrieved from https://www.geo.fu-berlin.de/en/geol/fachrichtungen/planet/press_rd/2019_lowell_crater/_content/faq_text/index.html4. NASA/JPL/Malin Space Science Systems5. www.lpi.usra.edu, http://www.planetary.brown.edu/planetary/documents/Micro_36/Abstracts/031_Head_etal.pdf6. Xie, Hongjie & Guana, H & Zhu, M & Thueson, M & Ackley, Stephen & Yue, Zongyu. (2019). Short communication A conceptual model for explanation of Albedo changes in Martian craters.7. Uahirise.org. (2019). HiRISE | Korolev Crater Layers (ESP_052267_2525). 8. European Space Agency. (2018). Perspective view of Korolev crater.9. Holo, S. J., Kite, E. S., and Robbins, S. J. (2018). Mars obliquity history constrained by elliptic crater orientations. Earth and Planetary Science Letters, 496, 206-214, doi: 10.1016/j.epsl.2018.05.04610. Barlow N. G.(2015). Constraining geologic properties and processes through the use of impact craters, Geomorphology, 240, 18-33, doi: 10.1016/j.geomorph.2014.08.027 11. https://mars.nasa.gov/news/nasa-mars-weathercam-helps-find-big-new-crater/ 12. Christensen, P.R., N.S. Gorelick, G.L. Mehall, and K.C. Murray, THEMIS Public Data Releases, Planetary Data System node, Arizona State University, <http://themis-data.asu.edu>.13. Brothers, T. C., and J. W. Holt (2016), Three-dimensional structure and origin of a 1.8km thick ice dome within Korolev Crater, Mars, Geophys. Res. Lett., 43, 1443–1449, doi:10.1002/ 2015GL06644014. Esa. (n.d.). Mars Express gets festive: A winter wonderland on Mars. Retrieved from https://www.esa.int/Our_Activities/Space_Science/Mars_Express/Mars_Express_gets_festive_A_winter_wonderland_on_MarsConway, S.J., Hovius, N., Barnie, T.,

Besserer, J., Le Mouélic, S., Orosei, R., Read, N.A., Climate-driven deposition of water ice and the formation of mounds in craters in Mars’ north polar region, Icarus, 220, 174-193, doi: 10.1016/j.icarus.2012.04.021, 2012.

15. Fenton, L. K. (2006). Dune migration and slip face advancement in the Rabe Crater dune field, Mars. Geophysical Research Letters,33(20). doi:10.1029/2006gl02713316. Formation of ring craters. (2018, September 12). Retrieved from https://www.geo.fu-berlin.de/en/geol/fachrichtungen/planet/press_rd/2019_lowell_crater/_content/faq_text/part3.html17. Lowell Crater - a bullseye on Mars. (n.d.). Retrieved from https://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10212/332_read-33595/year-all/332_page-1/#/gallery/3423218. Tirsch, D., Jaumann, R., Pacifici, A., and Poulet, F. ( 2011), Dark aeolian sediments in Martian craters: Composition and sources, J. Geophys. Res., 116, E03002, doi: 10.1029/2009JE003562.19. Lapotre, M. G. A. (2018), Seeing Mars in a grain of sand , Eos, 99, https://doi.org/10.1029/2018EO106925. Published on 17 October 2018.20. Conway, S.J., Hovius, N., Barnie, T., Besserer, J., Le Mouélic, S., Orosei, R., Read, N.A.: Climate-driven deposition of water ice and the formation of mounds in craters in Mars’ north polar region, Icarus, 220(1), 174-193, 2012.

References

We performed a case study on a selection of 3craters- Korolev Crater,- Lowell Crater, and- Rabe Crater.For this, we used satellite imagery from- HRSC/Mars Express,- THEMIS/Mars Odyssey,- HiRISE/Mars Reconnaissance Orbiter, andWe explored each of these craters as a wholeand some region(s) of interest. For thegeographic position of the 3 craters, see themap on the right.

IntroductionThe Mars surface is heavily cratered. As to that, catalogues provide statistically complete descriptions ofimpact craters down to ca. 1 km in diameter [1]. This includes a detailed specification of cratercharacteristics such as position, geometry, morphology, and degradation. In total, a number of severalhundred thousand craters are cataloged to date.Impact craters are a key proxy used for age-dating the Mars surface in a global sense and hold crucialimplications for the geologic history of Mars regarding volcanism and erosion processes [10]. In addition,craters allow for the reconstruction of Mars orbital parameters such as obliquity [9].Moreover, craters are promising for searching evidence of ancient life on Mars. That is because relatedimpact-induced hydrothermal systems may have sustained habitable conditions for tens to hundreds ofthousands of years. Compliant with that, Mars craters are a favorable field of study for Mars rovers.Craters are selected as landing sites for rovers, such as the Gale crater for the Curiosity rover and theJezero crater for the upcoming Mars2020 rover. In addition, the Opportunity rover visited several craterssuch as the Eagle crater, Endurance crater, Victoria crater, and Endeavour crater.

Methods and Materials

Mouza Al Amiri1, Rawdha Al Beshr1, Claus Gebhardt2, and Abdelgadir Abuelgasim2,3

1Department of Physics, College of Science, United Arab Emirates University, Al Ain 15551, United Arab Emirates, 201705722@uaeu.ac.ae, 201700281@uaeu.ac.ae 2National Space Science and Technology Center, United Arab Emirates University, Al Ain 15551, United Arab Emirates, claus.gebhardt@uaeu.ac.ae 3Geography and Urban Planning Department, College of Humanities and Social Sciences, United Arab Emirates University, Al Ain 15551, United Arab Emirates

The Rabe Crater

Rabe crater is in the Noachis Terra region (west of Hellas Basin) (43.9°S, 34.8°E), the diameter is~108 km. There is a large sand sheet with surface dunes on Rabe Crater [Fig. 3A,B]. The dunes arecolored dark and their height ranges are from 150 to 200 meters or more. They are mostly composedof transverse and barchanoid dunes [Fig. 3D,E]. Dunes of this type are expected to migratedownwind by saltation processes (if not frozen or indurated). At the downwind side of the dunes,streak patterns have been identified in Narrow Angle images of MOC/MGS. These streaks indicategrainflow events (i.e. sand avalanches). This points towards the sand dunes being at least seasonallyand partially active. The estimated sand dune migration rate is 1-2 cm per Martian Year [15].The Rabe Crater hosts an intracrater pit. At the pit walls, there is an exposed layer of dark basalticmaterial of volcanic origin. This indicates that the dark sand dunes in Rabe Crater have a localsource rather than sand being blown from outside into the crater (this is likely similar for othercraters with dark sand dunes) [18].Another interesting field of study are the Bagnold Dunes in Gale Crater. They were investigated by acampaign of the Mars Rover Curiosity from November 2015 to April 2017 [19].

The Lowell CraterLowell Crater is roughly 200 km in diameter. In its interior, there is a ring of mountains with adiameter of ca. 90 km [Fig. 4A-C]. Similar peak-rings are known from craters on the Earth,Venus, Mercury, and Moon. They form because of gravitational collapse and uplift of the floorduring the process of the formation [16]. The collapse of craters of a certain diameter can form acomplex interior structure with a flat bottom, central peaks, mountain rings [Fig.4D]The Lowell crater has large dark interior deposits of sand. These are separated into twodeposition areas by the mountain ring [Fig. 4A]. There is a compacted layer of sand in the innerdeposition area. A sand dune is discernible in the outer deposition area. These are mainlycrescent-shaped and barchanoid dunes [17].

The selected craters for this study are the Korolev Crater, Rabe Crater, and Lowell Crater. Thesecraters were selected because of interesting morphological features like ice traps, sand dunes,mountain rings, etc. This work is a student research project inspired by the discovery of theso-far-largest fresh impact crater during routine weather inspection of camera imagery fromMARCI/MRO [11].

Summary

The Korolev crater is located in the northern lowlands of Mars (latitude ca. 73°N). It isapproximately 82 km in diameter and 2 km deep. Also, it is surrounded by a 2 km high crater rim.An outstanding feature is the crater interior filled with a 1.8 km high mound of water ice[Fig. 2A,B,C]. The air over the ice cools down and becomes heavier than the surrounding air. Itthus increases thermal stability and acts as a “cold trap”, which shields the ice from disappearing[14]. The radar instrument SHARAD/MRO and HiRISE imagery at the edge of the ice moundindicate layered deposits of surface ice [Fig. 2C,D]. This layering indicates that the ice mound inKorolev Crater was formed by local deposition of surface ice rather than being part of a larger icesheet in the past [13].In total, more than 10 craters with water ice mounds are known at northern polar latitudes [20]. Inaddition to Korolev Crater, there are the Dokka and Louth Crater. The Louth Crater is located at alatitude of ca 70°N and is thus the southernmost crater with an all year long body of ice.

The Korolev Crater

List of Figures1. Mars Orbiter Laser Altimeter (MOLA), Goddard Space Flight Center, NASA.2. a. PERSPECTIVE VIEW OF KOROLEV CRATER, ID 412947 , ESA/DLR/FU Berlin

b. TOPOGRAPHIC VIEW OF KOROLEV CRATER, ID 412946, ESA/DLR/FU Berlin.c. Brothers and Holt(2016), Geophys. Res. Lett. (see also References, 13.), their Figure 4 d. Korolev Crater Layers, ESP_052280_2525, NASA/JPL/University of Arizona.

3. a. RABE CRATER, ID 310883, ESA/DLR/FU Berlin.b. RABE CRATER PRESPECTIVE, ID 310887, ESA/DLR/FU Berlin.c. HTTPS://WWW.JPL.NASA.GOV/SPACEIMAGES/DETAILS.PHP?ID=PIA22145d. HTTPS://WWW.JPL.NASA.GOV/SPACEIMAGES/DETAILS.PHP?ID=PIA22145e. Rabe Crater Dunes, ESP_055160_1360, NASA/JPL/University of Arizona.

4. a. PERSPECTIVE VIEW OF LOWELL CRATER, ID 421132, ESA/DLR/FU Berlin.b. Christensen, P.R., N.S. Gorelick, G.L. Mehall, and K.C. Murray, THEMIS Public Data Releases, Planetary Data Systemnode, Arizona State University, http://themis-data.asu.edu IMAGE ID V57922003

c. Lowell Crater, PIA19198, NASA/JPL-Caltech/ASU.d. https://www.geo.fu-berlin.de/en/geol/fachrichtungen/planet/press_rd/2019_lowell_crater/index.htmlImage Credit: modified after Melosh 1989

Fig. 2B: Topographic MapFig. 2A: HRSC Image of Korolev Crater Fig. 2D: HiRISE image

Fig. 2C: Crater cross-section from SHARAD/MRO

Fig. 3A: HRSC Image Fig. 3B: HRSC Image

Fig. 3C: Map of Rabe Crater

Fig. 3D: THEMIS VIS Image

FIGURE 3C

Fig. 3E: HiRISE Image

Background image:EXOMARS IMAGES KOROLEV CRATER, ID 393361, ESA/Roscosmos/CaSSIS

Fig. 4A: HRSC Image Fig. 4B: Map of Lowell CraterFig. 4D: Peak ring formation

Korolev crater

Rabe craterLowell crater

Fig. 4C : THEMIS VIS Image