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Nanoparticles of iridium and other platinum group elements identified in Chicxulub asteroid impact spherules – Implications for impact winter and profound climate change

Vajda, Vivi ; Nehzati, Susan LU ; Kenny, Gavin ; Bermúdez, Hermann D. ; Krüger, Ashley ; Björling, Alexander LU ; Ocampo, Adriana ; Cui, Ying and Sigfridsson Clauss, Kajsa G.V. LU (2025) In Global and Planetary Change 245.
Abstract

The Chicxulub asteroid that ended the Cretaceous Era ∼66.05 million years ago caused a prolonged time of global darkness – the impact winter – leading to mass extinctions. Elements from the asteroid, including the platinum group elements (PGEs) osmium, iridium and platinum are known from the globally distributed boundary clay but their carrier elements have so far been unknown. We identify, for the first time in detail, the presence of these PGEs within Chicxulub impact spherules and importantly, we identify their carrier elements. We show through synchrotron Nano-XRF how these PGEs occur in nanostructures as un-ordered cube- and/or needle-like crystals co-localizing with both siderophile and chalcophile elements including Co, Ni, Cu,... (More)

The Chicxulub asteroid that ended the Cretaceous Era ∼66.05 million years ago caused a prolonged time of global darkness – the impact winter – leading to mass extinctions. Elements from the asteroid, including the platinum group elements (PGEs) osmium, iridium and platinum are known from the globally distributed boundary clay but their carrier elements have so far been unknown. We identify, for the first time in detail, the presence of these PGEs within Chicxulub impact spherules and importantly, we identify their carrier elements. We show through synchrotron Nano-XRF how these PGEs occur in nanostructures as un-ordered cube- and/or needle-like crystals co-localizing with both siderophile and chalcophile elements including Co, Ni, Cu, Zn, and Pb, derived from the asteroid. These crystals are set within a matrix of iron-rich calcium and silica glass revealing the mix of vaporized target rock and the asteroid. The results provide insights into the combination of elements present in the spherules, indicating formation of new minerals. We argue that the nano-shards of unreactive elements such as platinum, iridium and copper acted as nuclei for aerosol formation and potentially contributed to a prolonged impact winter with darkness and cooling leading to a profound and long-term climate change.

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author
; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Aerosol, EDS, Gorgonilla Island, K–Pg, Mass extinction, Osmium, Synchrotron, XANES
in
Global and Planetary Change
volume
245
article number
104659
publisher
Elsevier
external identifiers
  • scopus:85211024780
ISSN
0921-8181
DOI
10.1016/j.gloplacha.2024.104659
language
English
LU publication?
yes
id
eabf6886-ecad-477c-98c7-b5a3811a9494
date added to LUP
2025-03-03 15:57:40
date last changed
2025-04-04 14:24:40
@article{eabf6886-ecad-477c-98c7-b5a3811a9494,
  abstract     = {{<p>The Chicxulub asteroid that ended the Cretaceous Era ∼66.05 million years ago caused a prolonged time of global darkness – the impact winter – leading to mass extinctions. Elements from the asteroid, including the platinum group elements (PGEs) osmium, iridium and platinum are known from the globally distributed boundary clay but their carrier elements have so far been unknown. We identify, for the first time in detail, the presence of these PGEs within Chicxulub impact spherules and importantly, we identify their carrier elements. We show through synchrotron Nano-XRF how these PGEs occur in nanostructures as un-ordered cube- and/or needle-like crystals co-localizing with both siderophile and chalcophile elements including Co, Ni, Cu, Zn, and Pb, derived from the asteroid. These crystals are set within a matrix of iron-rich calcium and silica glass revealing the mix of vaporized target rock and the asteroid. The results provide insights into the combination of elements present in the spherules, indicating formation of new minerals. We argue that the nano-shards of unreactive elements such as platinum, iridium and copper acted as nuclei for aerosol formation and potentially contributed to a prolonged impact winter with darkness and cooling leading to a profound and long-term climate change.</p>}},
  author       = {{Vajda, Vivi and Nehzati, Susan and Kenny, Gavin and Bermúdez, Hermann D. and Krüger, Ashley and Björling, Alexander and Ocampo, Adriana and Cui, Ying and Sigfridsson Clauss, Kajsa G.V.}},
  issn         = {{0921-8181}},
  keywords     = {{Aerosol; EDS; Gorgonilla Island; K–Pg; Mass extinction; Osmium; Synchrotron; XANES}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Global and Planetary Change}},
  title        = {{Nanoparticles of iridium and other platinum group elements identified in Chicxulub asteroid impact spherules – Implications for impact winter and profound climate change}},
  url          = {{http://dx.doi.org/10.1016/j.gloplacha.2024.104659}},
  doi          = {{10.1016/j.gloplacha.2024.104659}},
  volume       = {{245}},
  year         = {{2025}},
}