An Eoarchean continental nucleus for the Fennoscandian Shield and a link to the North Atlantic craton
Research output: Contribution to journal › Journal article › Research › peer-review
Enabling the build-up of continental crust is a vital step in the stabilization of cratonic lithosphere. However, these initial crustal nuclei are commonly either destroyed by recycling or buried by younger rocks. In the Fennoscandian Shield, the oldest rocks are ca. 3.5 Ga, but ca. 3.7 Ga inherited and detrital zircons suggest the presence of an older, unexposed crustal substrate. We present U-Pb, O, and Hf isotope data from detrital zircons of three major Finnish rivers as well as zircon O and Hf isotope data from previously dated rocks of the Archean Suomujärvi and Pudasjärvi complexes, central Finland. Combined, these data indicate a previously unidentified ca. 3.75 Ga crustal nucleus in the Fennoscandian Shield. This adds to the growing number of Eoarchean nuclei recognized in Archean terranes around the globe, highlighting the importance of such nuclei in enabling the growth of continental crust. The isotope signatures of the Fennoscandian nucleus correlate with equivalent-aged rocks in Greenland, consistent with a common Eoarchean evolution for Fennoscandia and the North Atlantic craton.
| Original language | English |
|---|---|
| Journal | Geology |
| Volume | 52 |
| Issue number | 3 |
| Pages (from-to) | 171-175 |
| ISSN | 0091-7613 |
| DOIs | |
| Publication status | Published - 2024 |
Bibliographical note
Funding Information:
Financial support by the Danish Independent Research Fund, DFF–Research Project 2 (grant 9040-0374B to Waight) is gratefully acknowledged. Kemp acknowledges an Australian Research Council (ARC) Future Fellowship (FT10010059). Hf isotope analysis at University of Western Australia was conducted with instrumentation funded by the ARC (grants LE100100203 and LE150100013). Matti Kurhila at GTK (Geological Survey of Finland) is thanked for providing the Pudasjärvi samples. Bin Fu is thanked for assistance during zircon O isotope analyses of igneous zircon. Valley has received funding from the European Research Council under the Horizon 2020 research and innovation program (grant agreement 856555). WiscSIMS is supported by the U.S. National Science Foundation (grant EAR-2004618) and the University of Wisconsin–Madison. The NordSIMS ion microprobe facility operates as Swedish-Icelandic infrastructure, partly funded by the Swedish Research Council (grant 2021-00276). This is NordSIMS contribution #747.
Publisher Copyright:
© 2023 Geological Society of America. For permission to copy, contact editing@geosociety.org.
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