Recently, the Planetary Science Group at the School of Space Science and Technology, Shandong University, together with collaborators from several research institutions, has identified andesite for the first time in Utopia Planitia on Mars through the analysis of in-situ data collected by the Zhurong rover. This finding was published online in Science Bulletin, under the title "Discovery of andesite in the northern plain of Mars: Insights from Zhurong's in situ observations." Ph.D. student Su Mingyu and associate researcher Liu Changqing of Shandong University are co-first authors. Professor Ling Zongcheng of Shandong University, Researcher Shu Rong of the Shanghai Institute of Technical Physics, and Researcher Zeng Xiaojia of the Institute of Geochemistry are co-corresponding authors.

The Martian crust has been thought to be homogeneous basaltic for a long time, reflecting a relatively limited degree of magmatic evolution. Early orbital observations by the Mars Global Surveyor revealed the widespread occurrence of andesite across the northern lowland plains of Mars. However, subsequent in-situ observations by the Mars Pathfinder mission suggested that these rocks might instead represent silica-rich weathering rinds formed through acidic alteration of basaltic rocks. In recent years, the Curiosity and Perseverance rovers have identified a variety of felsic alkaline rocks in the southern highlands of Mars, while highly evolved igneous clasts have also been discovered in the Martian breccia meteorite NWA 7034. These findings have prompted a reassessment of the complexity of magmatic evolution on Mars.

However,a key scientific question remains open: Did evolved andesitic magmatism occur in the northern hemisphere of Mars? The in-situ exploration of Utopia Planitia in northern Mars by Zhurong rover has provided anunprecedented‌ opportunity to address this question.

Figure 1 Traverse route of the Zhurong rover and Martian surface rocks investigated along its path.

This study employed the Mars Surface Composition Detector (MarSCoDe) onboard the Zhurong rover to establish a machine learning model for analyzing the elemental compositions of Martian rocks. The results show that rocks investigated by Zhurong rover before Sol 110 exhibit basaltic to basaltic-andesitic compositions, whereas those analyzed during 200–300 sols display high-silica and andesitic composition. The discovery of andesite by the Zhurong rover in Utopia Planitia provides evidence that highly evolved magmatic activity persisted on Mars until the late Amazonian period.

Figure 2 Total alkali–silica (TAS) diagram of the targets analyzed by the Zhurong rover. Red stars indicate the andesitic rocks identified by Zhurong.

Based on this finding, this study proposed a novel ice-assisted petrogenetic model for Martian andesite, suggesting that its parental magma may have undergone extensive fractional crystallization under high-pressure and hydrous conditions. According to the model, an ancient ocean may have once existed in the northern plains of Mars, which subsequently developed a thick ice sheet as the Martian climate cooled. The overburden pressure exerted by the ice sheet could have suppressed the rapid eruption of basaltic magma, allowing it to remain in magma reservoirs for a long period and thereby promoting extensive fractional crystallization. As the Martian ice sheet gradually melted and sublimated, the reduction in overburden pressure may have triggered decompression melting within the magmatic system, leading to the eruption of andesitic magma onto the surface. The discovery of the andesite suggests that the Martian crust may have experienced more extensive melting and magmatic differentiation than previously recognized, indicating that the red planet may have been more geologically active than previously thought.

Figure 3 Schematic illustration of andesite formation through ice–magma interactions in the northern plains of Mars.

These findings provide new insights into the diversity of Martian igneous rocks and the planet's recent volcanic activities, offering valuable implications for understanding lithospheric formation and the evolution of habitable environments on terrestrial planets in the Solar System. This research was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, and the Natural Science Foundation of Shandong Province, among other funding sources.

Shandong University’s Planetary Science Group (SDU-PSG) has made significant contributions to China’s Tianwen-1 Mars exploration mission. Since 2015, the group has developed a LIBS system coupled with a Mars Environment Simulation Chamber. They developed spectral libraries, established machine learning approaches, and acquired chemical compositions through Tianwen-1 spectral analysis. The team has published nearly 40 research papers on laboratory analyses of Mars-related samples and Tianwen-1 scientific data.