^1,2Xiaolong Guo,^1,2Peixin Du,³Hongmei Liu,⁴Jiacheng Liu,⁵Shangying Li,^1,2Xinyi Xiang,⁶Shun Wang,⁷Peng Yuan
Journal of Geophysical Research: Planets (in Press) Link to Article [https://doi.org/10.1029/2025JE009644]
¹State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Macau, China
²CNSA Macau Center for Space Exploration and Science, Macau, China
³Guangdong Provincial Key Laboratory ofMineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
⁴Department of Earth Sciences and Laboratory for Space Research, The University of Hong Kong, Hong Kong, China
⁵School of Land Engineering, Chang’an University, Xi’an, China
⁶Qinghai Provincial Key Laboratory of Geology andEnvironment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, China
⁷School ofEnvironmental Science and Engineering, Guangdong University of Technology, Guangzhou, China
Published by arrangement with John Wiley & Sons

Poorly ordered Al/Si phases are widely distributed across the surface of Mars, among which allophane and amorphous silica are the two main constituents. Both allophane and amorphous silica can form in Al-Si systems through surface chemical weathering or subsurface hydrothermal alteration of volcanic materials. Nevertheless, our comprehension of the products derived from Al-Si hydrolysis systems remains poorly constrained. Hydrolysis experiments were conducted on Al-Si systems across an unprecedentedly wide range of Si/(Al + Si) molar ratios (n, 0 ≤ n ≤ 0.9), followed by characterizing the products using multiple techniques. At n ≤ 0.1, the products consist predominantly of Al30 (an Al polycation with a Keggin structure) and poorly ordered Al hydroxides. The introduction of Si resulted in formation of a small amount of proto-allophane. At n = 0.2 and 0.3, poorly ordered materials were still dominant, along with the presence of well-crystallized bayerite and gibbsite. The proto-allophane increased in quantity and began to assemble into allophane. At n = 0.5, well-crystallized minerals were absent and allophane dominated the product. At n = 0.7, the amount of allophane decreased significantly and at n = 0.8 and 0.9, allophane was probably absent, although proto-allophane still formed. Meanwhile, an increasing amount of amorphous silica was formed. X-ray diffraction, Fourier transform infrared, and VNIR provide information for differentiating Al-rich phases and Si-rich phases but show limited capability in identifying poorly ordered Al/Si-rich phases. NMR is powerful for identifying poorly ordered Al/Si phases, although widespread iron on the martian surface and the large instrument pose challenges to its application on Mars.

^1,2,3Fengke Cao et al. (>10)
Journal of Geophysical Research: Planets (in Press) Link to Article [https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JE009228]
¹Research Center for Planetary Science, College of Earth and Planetary Sciences, Chengdu University of Technology,Chengdu, China
²Department of Earth Sciences, Western University, London, ON, Canada
³Institute for Earth & SpaceExploration, Western University, London, ON, Canada
Published by arrangement with John Wiley & Sons

Northwest Africa (NWA) 7034 and its paired meteorites represent polymict regolith breccias derived from the ancient Martian crust. We employed micro-X-ray diffraction and Raman spectroscopy to quantitatively assess impact-induced metamorphism in plagioclase and alkali feldspar. Strain-related mosaicity (SRM) was measured via full width at half maximum in the Debye ring or chi (χ) dimension (FWHMχ) from 2D XRD images. A total of 149 plagioclase and 21 alkali feldspar grains were analyzed. Plagioclase exhibits FWHMχ values from 0.5° to 10.9°, and alkali feldspar shows a range of 2.1°–9.7°. Plagioclase grains record peak shock pressures from 0 GPa (unshocked) to 28–30 GPa based on calibrations for experimentally shocked andesine. Approximately 26% of grains show no detectable shock deformation (<1.0 GPa), while ∼4% preserve evidence of severe shock (>21.0 GPa), indicative of exposure to at least moderate shock metamorphism prior to ejection from Mars. Alkali feldspar records higher apparent peak pressures, possibly spanning 4.7–28.5 GPa. Martian crustal minerals experienced highly heterogeneous shock effects, which highlights the complex and varied impact histories of feldspar minerals during the impact-induced brecciation process. Pressure differences between plagioclase and alkali feldspar may reflect distinct source regions, pre-lithification shock events, or differing shock responses. This study highlights the importance of multi-mineral analytical approaches to enhance the accuracy of shock pressure quantification in Martian regolith breccias and to reconstruct the planet’s impact processes. This methodology should also be applied to other extraterrestrial samples to characterize shock effects across planetary bodies in the solar system.

¹Pengyu Ren,¹Changqing Liu,¹Yuzhen Wang,¹Enming Ju,¹Xin Wang,¹Ruize Zhang,¹Yanqing Xin,¹Ying-Bo Lu,¹Zongcheng Ling
Journal of Geophysical Research: Planets (in Press) Link to Article [https://doi.org/10.1029/2025JE009532]
¹Shandong Key Laboratory of Space Environment and Exploration Technology, School of Space Science and Technology,Institute of Space Sciences, Shandong University, Weihai, China
Published by arrangement with John Wiley & Sons

The Mars Mineralogical Spectrometer (MMS) onboard the Tianwen-1 orbiter can obtain high-resolution visible and infrared reflectance spectra of the Martian surface, that supports detailed analysis of mineral types and their spatial distribution across Mars. However, raw MMS data cannot be directly applied to scientific analysis. To address this limitation, this paper develops a processing pipeline for MMS data, including radiance to I/F conversion, photometric correction, inhomogeneity correction, and geometric correction. Three global maps of ferric oxides were obtained using the processed MMS data. Results reveal that the ferric oxides are nearly ubiquitous across the Martian surface, and they primarily exist in the form of nanophase ferric oxides in the bright regions of Mars (e.g., Amazonis Planitia, Tharsis Montes, and Arabia Terra). Subsequently, the distribution of gray crystalline hematite is identified in Meridiani Planum and Aram Chaos using data from MMS. Additionally, a new deposit of red crystalline hematite is detected in the southeastern part of Aram Chaos. These findings provide crucial evidence for the existence of past aqueous environments in these regions, including Fe-rich aqueous fluids under ambient conditions, hydrothermal fluids, and in-place oxidative weathering of Fe-bearing rocks under the influence of surface water. Notably, the processing pipeline and methods established in this study are critical for advancing our understanding of the ferric oxide distribution across the Martian surface using MMS data.