“Mount Sharp is composed of stratified sedimentary rocks, as seen in a picture acquired by the Curiosity Rover’s MastCam instrument. The rover has been driving up into the rocks within these hills from the bottom of the Gale crater in order to understand how the rocks vary from lower in the section (older) to higher in the section (newer) (younger). Since the mission’s inception, the rover has explored rocks at a height of more than 400 meters. Photograph courtesy of NASA’s Mars Curiosity Rover”
NASA placed the rover Curiosity at the Gale crater on Mars in 2012 after several scientists hypothesized that the crater was the site of an old lake on Mars more than 3 billion years ago. Since then, the rover has been moving around for almost 3,190 sols, doing geological studies with its array of equipment (martian days, equivalent to 3278 earth days). After examining the data, experts from The University of Hong Kong’s (HKU) Faculty of Science’s Department of Earth Sciences have argued that the sediments recorded by the rover for the majority of the mission did not originate in a lake.
The study team hypothesized that the vast pile of sedimentary rocks examined and researched over the previous eight years is really made up of sand and silt deposited by air-fall and reworked by the wind. In a lake environment, the alteration of minerals produced by the interaction of water and sand did not occur. They argue that the “wet” environment really depicts weathering comparable to soil formation during rainfall in an ancient climate quite different from todays.
The discovery was just reported in Science Advances by Jiacheng LIU, his adviser Associate Professor Dr. Joe MICHALSKI, and co-author Professor Mei Fu ZHOU, all of whom are connected with the Department of Earth Sciences. The researchers utilized chemistry and x-ray diffraction (XRD) data, as well as pictures of rock textures, to determine how compositional patterns in rocks correspond to geological processes.
Knowledge of how the Martian atmosphere and surface environment formed is critical for both the search for life on Mars and our understanding of how the Earth may have altered throughout its early history. “ Clearly, researching Mars is exceedingly challenging, necessitating the use of innovative and technologically sophisticated techniques. Liu and co-authors have discovered fascinating discoveries on the chemical composition of ancient sediments that provide light on their early genesis by utilizing remote sensing techniques. Their findings cast doubt on previously held hypotheses about the depositional environment of these unique rock formations and the atmospheric conditions under which they formed – specifically, the authors demonstrate evidence for weathering processes in a subareal environment resembling a desert, rather than formation in an aqueous lake environment. Indeed, this study will serve as a springboard for new and interesting research directions.” Dr. Ryan McKenzie, an assistant professor at the Department of Earth Science, was also added.
In May of this year, China successfully landed its first lander on Mars, Zhurong. Zhurong is now traversing the plains of Utopia Planitia, looking for evidence of recent climatic change through mineralogical and chemical analysis. China is also preparing a sample return mission, which is expected to take place by the end of this decade.
About the HKU research team:
The Department of Earth Sciences, the Research Division for Earth and Planetary Scientific, and the Laboratory for Space Research are recognized experts in applying conventional Earth and environmental research methodologies and abilities to contemporary space science issues. Dr. Joe Michalski directs the Planetary Spectroscopy and Mineralogy Laboratory at HKU and serves as the Laboratory for Space Research’s Deputy Director.
