Mars once contained massive amounts of ice, and changes in its distribution and quantity serve as important clues for understanding climate change, but the overall picture has remained unclear until now.
Associate Professor Trishit Ruj from Okayama University's Institute for Planetary Materials and his team used high-resolution images from NASA spacecraft (HiRISE and CTX) to investigate more than 750 craters in the mid-latitudes. By combining landforms created by ice, crater dating, and climate models, they revealed changes in ice accumulation and distribution over the past approximately 600 million years.
The results revealed that ice consistently tends to accumulate on the southwestern sides of craters. This was found to be caused by "cold traps" created by reduced solar radiation and shadows. Furthermore, past ice accumulation occurred not once but 2-3 times, with each episode having different supply directions and thicknesses, influenced by climate changes associated with variations in Mars' rotational axis tilt.
Approximately 640 million years ago, ice was thick and widespread, but it subsequently decreased, with the last ice accumulation (around 98 million years ago) showing a limited distribution. This indicates that Mars transitioned from a humid era to a cold and arid era. This is important knowledge that contributes not only to understanding Mars' ice and climate history but also to the utilization of water resources in future exploration. The research was published in Geology.
Credit: Ruj, T. et al. / Okayama University, Institute for Planetary Materials
Ruj commented: "These results were obtained through international collaborative research with JAMSTEC, Università d'Annunzio in Italy, Kochi University, Brown University in the United States, JAXA, and the University of Tokyo. By utilizing high-resolution images from NASA's Mars exploration spacecraft and the analytical techniques of Okayama University's Institute for Planetary Materials, we have revealed details of Mars' ice history and climate change, which is expected to contribute to considerations for future spacecraft landing sites. Would you like to experience the exciting and thrilling research that unravels the mysteries of Mars with us?"
Journal Information
Publication: Geology
Title: Long-term and multi-stage ice accumulation in the martian mid-latitudes during the Amazonian
DOI: 10.1130/G53418.1
This article has been translated by JST with permission from The Science News Ltd. (https://sci-news.co.jp/). Unauthorized reproduction of the article and photographs is prohibited.