Becquerel (Martian crater)

Becquerel is a 167 km-diameter crater at 22.1°N, 352.0°E on Mars, in Arabia Terra in Oxia Palus quadrangle. It is named after Antoine H. Becquerel.

Photographs by the Mars Global Surveyor revealed layered sedimentary rocks in the crater.Mars Exploration: Multimedia The layers appear to be only a few meters thick and show little variations in thickness. Recent studies with HiRISE have determined the exact thickness of the layers. The 66 layers measured showed one group of layers to average and another group to average in thickness.Lewis, K. et al. 2008. Quasi-Periodic Bedding in the Sedimentary Rock Record of Mars. Science. 322:1532-1535 Patterns like this are usually produced on Earth through the effects of water; volcanic deposits would not produce ash or laval flows of such regular thickness and in any event, there are no nearby volcanic vents.HiRISE | Lots of Layering in Becquerel (PSP_003656_2015)

There are cyclic variations in the thickness of the exposed sedimentary layers, possibly indicating cyclic variations in environmental conditions while the sediment was being laid down.Grotzinger, J. and R. Milliken (eds.) 2012. Sedimentary Geology of Mars. SEPM Most of the layers are parallel to each other, suggesting they formed by vertical settling, but a few are cross-bedded, indicating that at the time that the layers were deposited the sediment was transported along the ground surface by wind or water. The sedimentary material appears to be easily eroded and active wind erosion may be continuing to the current day.Mars Odyssey Mission THEMIS: Feature Image: Becquerel Crater Deposit (Released 28 May 2002)

Parts of the mound in Becquerel crater show radial faults, These may be the result of a salt diapir. On Earth these are associated with methane seepage. Perhaps the methane detected on Mars from time to time is coming from these faults.Luzzi, E., et al. 2018. BECQUEREL CRATER RADIAL FAULTS: A POSSIBLE TARGET FOR METHANE SEEPAGE INVESTIGATION. 49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083). 1494.pdf

Some parts of Becquerel show light-toned layers. Light-toned rocks on Mars have been associated with hydrated minerals like sulfates. The Mars rover Opportunity examined such layers close-up with several instruments. Scientists are excited about finding hydrated minerals such as sulfates and clays on Mars because they are usually formed in the presence of water. Places that contain clays and/or other hydrated minerals would be good places to look for evidence of life.

Many craters once contained lakes.Cabrol, N. and E. Grin. 2001. The Evolution of Lacustrine Environments on Mars: Is Mars Only Hydrologically Dormant? Icarus: 149, 291-328.Fassett, C. and J. Head. 2008. Open-basin lakes on Mars: Distribution and implications for Noachian surface and subsurface hydrology. Icarus: 198, 37-56.Fassett, C. and J. Head. 2008. Open-basin lakes on Mars: Implications of valley network lakes for the nature of Noachian hydrology. Because some crater floors show deltas, we know that water had to be present for some time. Dozens of deltas have been spotted on Mars.Wilson, J. A. Grant and A. Howard. "Inventory of Equatorial Alluvial Fans and Deltas on Mars" 44th Lunar and Planetary Science Conference. 2013. Retrieved July 3, 2019. Deltas form when sediment is washed in from a stream entering a quiet body of water. It takes a bit of time to form a delta, so the presence of a delta is exciting; it means water was there for a time, maybe for many years. Primitive organisms may have developed in such lakes; hence, some craters may be prime targets for the search for evidence of life on the Red Planet.Newsom H., Hagerty J., Thorsos I. 2001. Location and sampling of aqueous and hydrothermal deposits in martian impact craters. Astrobiology: 1, 71-88.

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Becquerel (Martian crater)

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