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Zircons of the Sörvik granite – a link between the young Trans-scandinavian Igneous Belt and the pre-Svecofennian

Lindh, Anders LU and Scherstén, Anders LU orcid (2024) In GFF 146(1-2). p.64-71
Abstract

The Sörvik granite forms rounded intrusions in the dominating Revsund granite, north-eastern Jämtland, central Sweden. Laser-ablation single-collector magnetic sector field-inductively coupled plasma-mass spectrometry on zircons was used to date the granite. The zircons are inhomogeneous, some with evident cores. The fractionation curves, 207Pb/235U versus time (depth), are irregular and often inconsistent with expected curves due to inhomogeneities in the zircon crystals in the Sörvik granite making age determinations difficult. The best-constrained age is a Tera-Wasserburg concordia age of 1776 ± 9 Ma obtained from five points. An upper-intercept discordia age in the... (More)

The Sörvik granite forms rounded intrusions in the dominating Revsund granite, north-eastern Jämtland, central Sweden. Laser-ablation single-collector magnetic sector field-inductively coupled plasma-mass spectrometry on zircons was used to date the granite. The zircons are inhomogeneous, some with evident cores. The fractionation curves, 207Pb/235U versus time (depth), are irregular and often inconsistent with expected curves due to inhomogeneities in the zircon crystals in the Sörvik granite making age determinations difficult. The best-constrained age is a Tera-Wasserburg concordia age of 1776 ± 9 Ma obtained from five points. An upper-intercept discordia age in the 208Pb/232Th–207Pb/235U system obtained from six analyses with <|2.5|% discordance suggests an age of 1.74 . 103 Ma; these analyses give an identical 208Pb/207Pb age (age brackets ∼1.73 and ∼1.80 . 103Ma) supporting the U–Pb result. The suggested minimum age of a core and the inhomogeneities in the isotope composition of the crystals are consistent with a pre-Svecofennian age of the source rocks. These results, together with previously reported results from other rocks in the area, support earlier suggestions that the crust formation is no younger than early Palaeoproterozoic.

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type
Contribution to journal
publication status
published
subject
keywords
element fractionation, LA-SF-ICP-MS analyses, Zircon age, zircon cores
in
GFF
volume
146
issue
1-2
pages
8 pages
publisher
Taylor & Francis
external identifiers
  • scopus:105009533840
ISSN
1103-5897
DOI
10.1080/11035897.2025.2472347
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
id
a4a83f23-9df5-4b26-bf3a-ebdd4147b8f5
date added to LUP
2025-11-18 15:48:42
date last changed
2025-11-20 10:11:04
@article{a4a83f23-9df5-4b26-bf3a-ebdd4147b8f5,
  abstract     = {{<p>The Sörvik granite forms rounded intrusions in the dominating Revsund granite, north-eastern Jämtland, central Sweden. Laser-ablation single-collector magnetic sector field-inductively coupled plasma-mass spectrometry on zircons was used to date the granite. The zircons are inhomogeneous, some with evident cores. The fractionation curves, <sup>207</sup>Pb/<sup>235</sup>U versus time (depth), are irregular and often inconsistent with expected curves due to inhomogeneities in the zircon crystals in the Sörvik granite making age determinations difficult. The best-constrained age is a Tera-Wasserburg concordia age of 1776 ± 9 Ma obtained from five points. An upper-intercept discordia age in the <sup>208</sup>Pb/<sup>232</sup>Th–<sup>207</sup>Pb/<sup>235</sup>U system obtained from six analyses with &lt;|2.5|% discordance suggests an age of 1.74 <sup>.</sup> 10<sup>3</sup> Ma; these analyses give an identical <sup>208</sup>Pb/<sup>207</sup>Pb age (age brackets ∼1.73 and ∼1.80 <sup>.</sup> 10<sup>3</sup>Ma) supporting the U–Pb result. The suggested minimum age of a core and the inhomogeneities in the isotope composition of the crystals are consistent with a pre-Svecofennian age of the source rocks. These results, together with previously reported results from other rocks in the area, support earlier suggestions that the crust formation is no younger than early Palaeoproterozoic.</p>}},
  author       = {{Lindh, Anders and Scherstén, Anders}},
  issn         = {{1103-5897}},
  keywords     = {{element fractionation; LA-SF-ICP-MS analyses; Zircon age; zircon cores}},
  language     = {{eng}},
  number       = {{1-2}},
  pages        = {{64--71}},
  publisher    = {{Taylor & Francis}},
  series       = {{GFF}},
  title        = {{Zircons of the Sörvik granite – a link between the young Trans-scandinavian Igneous Belt and the pre-Svecofennian}},
  url          = {{http://dx.doi.org/10.1080/11035897.2025.2472347}},
  doi          = {{10.1080/11035897.2025.2472347}},
  volume       = {{146}},
  year         = {{2024}},
}