Mars climate change research: Perspective of sulfur replacing carbon in martian sedimentary rocks

The study is designed to characterize changes in environment on early Mars by comparing the sedimentary environment of Martian sedimentary rocks with terrestrial red beds, because of their similar depositional environments, mineral contents, and chemical compositions. First, the chemical compositions and mineral contents of Martian sedimentary rocks (analyzed by NASA's Mars Curiosity Rover from Gale crater) and terrestrial red beds on Earth (collected from previous research results) were compared. Changes in aqueous environments on Mars were then investigated by conducting experiments involving replacing carbonates with sulfate in terrestrial red beds. The results showed that the calcite was converted to gypsum in the experiments where sulfur replaced carbon. In light of these results, we suggest that as volcanic activity increased the carbon cycle that initially affected Martian sedimentary rock formations was gradually replaced by a sulfur cycle, and eventually sulfates replaced carbonates in Martian sedimentary rocks. The present research could potentially contribute to the fundamental understanding of the climate change on Mars.

Automated summary

The study compares the sedimentary environment and compositions of Martian sedimentary rocks and terrestrial red beds to characterize changes in the early Mars environment. Chemical compositions and mineral contents of Martian sedimentary rocks and terrestrial red beds were compared. Experiments replacing carbonates with sulfate in terrestrial red beds revealed that calcite was converted to gypsum. The results suggest that volcanic activity gradually replaced the carbon cycle with a sulfur cycle on Mars, leading to the replacement of carbonates with sulfates in Martian sedimentary rocks. This research contributes to the understanding of climate change on Mars.