^1,2,3Jun Zhang et al. (>10)
Earth and Planetary Science Letters 654, 119239 Link to Article [https://doi.org/10.1016/j.epsl.2025.119239]
¹Key Laboratory of Mountain and Surface Process, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
²State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China
³University of Chinese Academy of Sciences, Beijing 100049, China
Copyright Elsevier

Grain size distribution (GSD) is crucial for understanding soil properties and surface processes. We find that both terrestrial soils and lunar soils are subjected to a unified GSD function, P(D)= g(μ)D-μexp(-D/Dc), reducing the textural fractions and grade modes to a parameter pair (μ, Dc), which unifies terrestrial and extraterrestrial soils in granular configuration, beyond the environments and mechanisms of soil genesis. To construct a framework of the soil formation, we generalize the textural composition to a grade space representing the granular configuration, and conceptualize soil genesis as the random aggregation of the fractal fragmentation of parent lithospheric material and fragments from other sources (e.g., meteorites impacts or surface transport processes). Random simulation reproduces the multiple grade modes observed in soils, and spontaneously derives the unified GSD function. Then we numerically generate the (μ, Dc)-fields for soils on earth and moon, which refine the digital data mapping based on site measurements and depict the local fluctuation of soil parameters. The GSD unity also provides a tool of generating “numerical simulants” of lunar soils to fill the gap in material simulants. The study leads to a GSD-paradigm (in contrast to the conventional landscape-paradigm) in soil study, which is expected to facilitate the data harmonization on earth and promote the generation of lunar regolith data in favor of the in-situ resource utilization and base construction on moon.

¹Daniel O. Cukierski,¹David W. Peate,^1,2Ingrid A. Ukstins,¹Christy Kloberdanz,¹C. Tom Foster,^1,3Chungwan Lim
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14322]
¹Department of Earth & Environmental Sciences, University of Iowa, Iowa City, Iowa, USA
²School of Environment, The University of Auckland, Auckland, New Zealand
³Department of Earth Science Education, Kongju National University, Kongju, Chungnam, Republic of Korea
Published by arrangement with John Wiley & Sons

Samples of impactite from the small (~350 m diameter) Monturaqui crater in northern Chile contain Fe-Ni metallic spherules sourced from the iron meteorite impactor. Textural characterization and quantification were done using SEM and μCT data. Two textural types are distinguished, with different size distributions. The smaller spherical objects (mostly <100 μm in diameter) follow a power law size distribution, while larger objects are mostly irregular-shaped patches. These are analogous to the small (nm to 50 μm) immiscible spherical metal droplets and large (150–500 μm) irregular partly fused pieces of the iron meteorite projectile observed in highly shocked ejecta fragments during hypervelocity impact experiments. Compositions of both spherule types were determined using in situ methods (electron microprobe, LA-ICP-MS), as well as solution ICP-MS on individual spherules separated from impact melt glass using electric pulse disintegration. Spherules are enriched in Ni and Co relative to Fe and W and relative to the inferred iron meteorite impactor composition, and PGEs show similar enrichments with limited fractionation between different PGEs, all consistent with selective oxidation processes. All spherules have similar chondrite-normalized patterns that are also broadly similar to weathered fragments of the iron meteorite impactor. Ni-Ge and Ni-Ir data on large (>300 μm) spherules and weathered meteorite fragments suggest that the Monturaqui impactor was a group IAB iron meteorite.