Show simple item record

dc.contributor.authorAlwmark, C.
dc.date.accessioned2021-02-12T22:53:47Z
dc.date.available2021-02-12T22:53:47Z
dc.date.issued2009-01-01
dc.identifier.citationAlwmark, C. (2009). Shocked quartz grains in the polymict breccia of the Granby structure, Sweden—Verification of an impact. Meteoritics & Planetary Science, 44(8), 1107-1113.
dc.identifier.issn1945-5100
dc.identifier.doi10.1111/j.1945-5100.2009.tb01210.x
dc.identifier.urihttp://hdl.handle.net/10150/656599
dc.description.abstractThe Middle Ordovician Granby structure in Sweden is generally considered the result of an asteroidal or cometary collision with Earth, although no hard evidence, i.e., shock metamorphic features or traces of the impactor, have been presented to date. In this study, drill core samples of a sedimentary breccia from the Granby structure have been investigated for microscopic shock metamorphic evidence in an attempt to verify the impact genesis of the structure. The finding of multiple sets of decorated planar deformation features (PDFs) in quartz grains in these samples provides unambiguous evidence that the structure is impact derived. Furthermore, the orientation of the PDFs, e.g., omega {1013}, pi {1012} and r, z {1011}, is characteristic for impact deformation. The fact that a majority of the PDFs are decorated implies a water-bearing target. The shocked quartz grains can be divided into two groups; rounded grains found in the breccia matrix likely originated from mature sandstone, and angular grains in fragments from crystalline target rocks. The absence of melt particles provides an estimated maximum shock pressure for the sedimentary derived quartz of 15-20 GPa and the frequency distribution of PDF orientations in the bedrock quartz implies pressures of the order of 10 GPa.
dc.language.isoen
dc.publisherThe Meteoritical Society
dc.relation.urlhttps://meteoritical.org/
dc.rightsCopyright © The Meteoritical Society
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectshock metamorphism
dc.subjectImpact crater Granby
dc.subjectterrestrial craters
dc.subjectSweden
dc.titleShocked quartz grains in the polymict breccia of the Granby structure, Sweden—Verification of an impact
dc.typeArticle
dc.typetext
dc.identifier.journalMeteoritics & Planetary Science
dc.description.collectioninformationThe Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.
dc.eprint.versionFinal published version
dc.description.admin-noteMigrated from OJS platform February 2021
dc.source.volume44
dc.source.issue8
dc.source.beginpage1107
dc.source.endpage1113
refterms.dateFOA2021-02-12T22:53:47Z


Files in this item

Thumbnail
Name:
15758-18111-1-PB.pdf
Size:
893.5Kb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record