Mineral crusts and mold holes in Martian rocks: Evidence of microbes on ancient Mars

Hong-Xia Jiang¹, Ya-Sheng Wu^2,3*, Li-Jing Liu⁴, Gong-Liang Yu⁵, Xiao-Qun Yang⁶

¹Hebei Key Laboratory of Strategic Critical Mineral Resources, Hebei GEO University, Shijiazhuang 050031, China. jianghx@hgu.edu.cn

²University of Chinese Academy of Sciences, Beijing 100049, China.

³Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China. wys@mail.igcas.ac.cn

⁴State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, 710069, Xi’an, China. liulijing@nwu.edu.cn

⁵Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei Province, China. yugl@ihb.ac.cn

⁶Sinopec Petroleum Exploration and Production Research Institute, Beijing 100083, China. yangxq873.syky@sinopec.com

^*corresponding author: wys@mail.igcas.ac.cn.

Abstract

Experimental studies and observations of modern microbialites in natural environments indicate that the metabolic action of some microbes can cause minerals to precipitate on their surface and form crusts enclosing the microbes. The holes left by degradation of died microbes are called mold holes. Mineral crusts and mold holes are widespread in present and ancient microbial rocks on Earth and are evidence of once presence of microbes. Structures similar to Earth’s fossils and stromatolites and organic compounds have been found in previous studies on the photographs of Martian rocks taken by the Perseverance rover, suggesting that the Mars may have supported life. Based on an analysis of the photos by NASA's Perseverance rover in July 2022, of two drilling cores and a circular abraded surface at the Jezero crater area of Mars, this paper reports that the Martian rocks have dense mineral crusts and mold holes, suggesting that they were formed by microbial-induced precipitation, confirming the once presence of microbial communities on ancient Mars. Based on the size of the mold holes, the microbes that formed the rocks are probably cyanobacteria.

Key words: Mars, life, mineral crust, mold hole, microbialites, biolith, microbiolith

Cite it as:  Jiang, H.X., Wu, Y.S., Liu, L.J., Yu, G.L., Yang, X.Q. 2024. Mineral crusts and mold holes in Martian rocks: Evidence of microbes on ancient Mars. Biopetrology, 4(1): 1-9. https://biopetrology.com/upload/mcamhi.pdf