Chrome-rich spinels in micrometeorites from modern Antarctic sedimentary deposits

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

  • Van Maldeghem, Flore Sonja J
  • Ryoga Maeda
  • Bastien Soens
  • Martin D. Suttle
  • Lisa Krämer Ruggiu
  • Carole Cordier
  • Akira Yamaguchi
  • Birger Schmitz
  • Philippe Claeys
  • Luigi Folco
  • Steven Goderis

Each year, approximately 5000 tons of extraterrestrial material reaches the Earth's surface as micrometeorites, cosmic dust particles ranging from 10 to 2000 μm in size. These micrometeorites, collected from diverse environments, mainly deep-sea sediments, Antarctic ice, snow and loose sediments, and hot deserts, are crucial in understanding our Solar System's evolution. Chrome-rich spinel (Cr-spinel) minerals have gained attention as proxies for studying the extraterrestrial flux in sedimentary deposits, because these robust minerals occur, in various extraterrestrial materials, with compositions characteristic of their parent bodies. A total of 27 Cr-spinel bearing micrometeorites within the size range of 185–800 μm, were identified from approximately 6000 micrometeorites from the Transantarctic Mountains (n = 23) and the Sør Rondane Mountains (n = 4), in Antarctica, containing Cr-spinel (8–120 μm), were examined in this study for geochemical composition and high-precision oxygen isotope ratios to assess alteration and identify potential parent bodies. Oxygen isotopes in the micrometeorite groundmass and in Cr-spinel grains reveal a predominance of ordinary chondritic precursors, with only 1 in 10 micrometeorites containing Cr-spinel minerals showing a carbonaceous chondritic signature. This may be further confirmed by an elevated Al content (> 12 wt% Al2O3) in Cr-spinel from specific carbonaceous chondrite types, but a more extensive dataset is required to establish definitive criteria. The first Cr-spinel bearing particle, in an Antarctic micrometeorite, that can be linked to R-chondrites based on oxygen isotopes, has been documented, demonstrating the potential for R-chondrites as a source of chrome-rich spinels. The study also highlights the potential for chemical modifications and alteration processes that Cr-spinel minerals may undergo during their time on the parent body, atmospheric entry, and terrestrial residence. In the context of the broader micrometeorite flux, the results align with previous findings, showing a consistent contribution of micrometeorites containing Cr-spinel minerals related to ordinary chondrites over the past 2 to 4 million years. This is however a small fraction (∼ 1 %) of the total micrometeorite flux. The study further confirms that Cr-spinel minerals recovered from sedimentary deposits serve as valuable proxies for tracking events related to ordinary chondritic or achondritic materials. However, it is emphasized that Cr-spinel minerals alone cannot serve as exclusive indicators of the overall extraterrestrial flux, especially during periods dominated by carbonaceous chondritic dust in the inner Solar System. To comprehensively understand the complete extraterrestrial flux, additional proxies are needed to trace dust-producing events associated with various Solar System objects. The intricate nature of Cr-spinel compositions, and the potential for alteration processes emphasize the need for further research to refine our understanding of these extraterrestrial markers.

OriginalsprogEngelsk
Artikelnummer118837
TidsskriftEarth and Planetary Science Letters
Vol/bind641
Antal sider15
ISSN0012-821X
DOI
StatusUdgivet - 2024

Bibliografisk note

Funding Information:
We would like to thank Johan Villeneuve (CRPG) and Rei Kanemaru for their assistance during the SIMS measurement time and the EMPA analysis, respectively. We would also like to thank the Research Foundation Flanders (FWO) for funding this PhD research to FVM (research project 11C2520N ). RM acknowledges support from JSPS KAKENHI Grant Number JP23K19080 , and thanks NIPR International Internship Program for Polar Science 2021 for financial and analytical support. RM, PhC and SG acknowledge support from the Excellence of Science (EoS) project \u2018\u2018ET-HoME\u201D. SG and PC acknowledge the support by the Belgian Science Policy (BELSPO) through the BELAM, Amundsen, BAMM and DESIRED projects. SG and PC also thank the Research Foundation - Flanders (FWO \u2013 Vlaanderen), and the VUB strategic research. We thank RVM and GP for the XRF measurements. We thank Philipp Heck and 1 anonymous reviewer as well as editor Frederic Moynier for their detailed comments and suggestions that helped to improve this manuscript significantly.

Publisher Copyright:
© 2024

ID: 398077587