Journal article
Textural and compositional characteristics of metallic spherules in impact melt from Monturaqui crater, Chile
Meteoritics & planetary science, Vol.60(3), pp.646-662
03/2025
DOI: 10.1111/maps.14322
Appears in UI Libraries Support Open Access
Abstract
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.
Details
- Title: Subtitle
- Textural and compositional characteristics of metallic spherules in impact melt from Monturaqui crater, Chile
- Creators
- Daniel O. Cukierski - University of IowaDavid W. Peate - University of IowaIngrid A. Ukstins - University of IowaChristy Kloberdanz - University of IowaC. Tom Foster - University of IowaChungwan Lim - Kongju National University
- Resource Type
- Journal article
- Publication Details
- Meteoritics & planetary science, Vol.60(3), pp.646-662
- Publisher
- Wiley
- DOI
- 10.1111/maps.14322
- ISSN
- 1086-9379
- eISSN
- 1945-5100
- Grant note
- National Aeronautics and Space Administration: 06-PGG06-6 NASAUniversity of Iowa MPSFPGeological Society of America Student Research GrantMax & Lorraine Littlefield Fund
Field collection of samples was funded by NASA grant 06-PGG06-6 to Ukstins. Analytical work was funded by a University of Iowa MPSFP grant to Peate, a Geological Society of America Student Research Grant to Cukierski, and the Max & Lorraine Littlefield Fund to Kloberdanz. The following people are thanked for invaluable assistance with analytical work: Des Petterson & Alex Weh (SelFrag), Ellery Frahm (Minnesota EMP), Mike Rowe (WSU EMP), Lukas Baumgartner & Benita Putlitz (Lausanne mu CT), Jay Thompson (LA-ICP-MS), Ed Gillan (U of Iowa Chemistry). We thank Christopher Hamann and Matthias Ebert for their constructive reviews of an earlier version of the manuscript.
- Language
- English
- Electronic publication date
- 02/06/2025
- Date published
- 03/2025
- Academic Unit
- Honors Program; Earth and Environmental Sciences
- Record Identifier
- 9984790977502771
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