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Impact melt rocks from the Late Paleocene Hiawatha impact structure, northwest Greenland

Hyde, William R. LU orcid ; Garde, Adam A. ; Keulen, Nynke ; Malkki, Sebastian N. ; Jaret, Steven J. ; Waight, Tod ; Beck, Pierre ; McDonald, Iain and Larsen, Nicolaj K. LU (2023) In Meteoritics and Planetary Science 58(6). p.789-814
Abstract

Impact melt rocks formed during hypervelocity impact events are ideal for studying impact structures. Here, we describe impact melt rock samples collected proximal to the 31 km wide 58 Ma Hiawatha impact structure, northwest Greenland, which is completely covered by the Greenland Ice Sheet. The melt rocks contain diagnostic shock indicators (e.g., planar deformation features [PDF] in quartz and shocked zircon) and form three groups based on melt textures and chemistry: (i) hypocrystalline, (ii) glassy, and (iii) carbonate-based melt rocks. The exposed foreland directly in front of the structure consists of metasedimentary successions and igneous plutons; however, the carbonate-based impactites indicate a mixed target sequence with a... (More)

Impact melt rocks formed during hypervelocity impact events are ideal for studying impact structures. Here, we describe impact melt rock samples collected proximal to the 31 km wide 58 Ma Hiawatha impact structure, northwest Greenland, which is completely covered by the Greenland Ice Sheet. The melt rocks contain diagnostic shock indicators (e.g., planar deformation features [PDF] in quartz and shocked zircon) and form three groups based on melt textures and chemistry: (i) hypocrystalline, (ii) glassy, and (iii) carbonate-based melt rocks. The exposed foreland directly in front of the structure consists of metasedimentary successions and igneous plutons; however, the carbonate-based impactites indicate a mixed target sequence with a significant carbonate-rich component. Well-preserved organic material in some melt rocks indicates that North Greenland at the time of impact was host to abundant organic material, likely a dense high-latitude temperate forest. Geochemical signatures of platinum-group elements in selected samples indicate an extraterrestrial component and support previous identification of a highly fractionated iron impactor in glaciofluvial sand. Our results illustrate the possibility to study impact structures hidden beneath a thick ice sheet based on transported samples and this opens a new avenue for identifying other potential impact craters in Greenland and Antarctica.

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author
; ; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Impact melt, Hiawatha, PGE, Shock metamorphism
in
Meteoritics and Planetary Science
volume
58
issue
6
pages
26 pages
publisher
Wiley-Blackwell
external identifiers
  • scopus:85159873813
ISSN
1086-9379
DOI
10.1111/maps.13987
language
English
LU publication?
no
additional info
Publisher Copyright: © 2023 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society.
id
4c6af4df-1463-46aa-9f3d-604daaece1ee
date added to LUP
2024-04-10 11:54:37
date last changed
2024-04-11 11:57:15
@article{4c6af4df-1463-46aa-9f3d-604daaece1ee,
  abstract     = {{<p>Impact melt rocks formed during hypervelocity impact events are ideal for studying impact structures. Here, we describe impact melt rock samples collected proximal to the 31 km wide 58 Ma Hiawatha impact structure, northwest Greenland, which is completely covered by the Greenland Ice Sheet. The melt rocks contain diagnostic shock indicators (e.g., planar deformation features [PDF] in quartz and shocked zircon) and form three groups based on melt textures and chemistry: (i) hypocrystalline, (ii) glassy, and (iii) carbonate-based melt rocks. The exposed foreland directly in front of the structure consists of metasedimentary successions and igneous plutons; however, the carbonate-based impactites indicate a mixed target sequence with a significant carbonate-rich component. Well-preserved organic material in some melt rocks indicates that North Greenland at the time of impact was host to abundant organic material, likely a dense high-latitude temperate forest. Geochemical signatures of platinum-group elements in selected samples indicate an extraterrestrial component and support previous identification of a highly fractionated iron impactor in glaciofluvial sand. Our results illustrate the possibility to study impact structures hidden beneath a thick ice sheet based on transported samples and this opens a new avenue for identifying other potential impact craters in Greenland and Antarctica.</p>}},
  author       = {{Hyde, William R. and Garde, Adam A. and Keulen, Nynke and Malkki, Sebastian N. and Jaret, Steven J. and Waight, Tod and Beck, Pierre and McDonald, Iain and Larsen, Nicolaj K.}},
  issn         = {{1086-9379}},
  keywords     = {{Impact melt; Hiawatha; PGE; Shock metamorphism}},
  language     = {{eng}},
  number       = {{6}},
  pages        = {{789--814}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Meteoritics and Planetary Science}},
  title        = {{Impact melt rocks from the Late Paleocene Hiawatha impact structure, northwest Greenland}},
  url          = {{http://dx.doi.org/10.1111/maps.13987}},
  doi          = {{10.1111/maps.13987}},
  volume       = {{58}},
  year         = {{2023}},
}