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An Eoarchean continental nucleus for the Fennoscandian Shield and a link to the North Atlantic craton
Geology ( IF 5.8 ) Pub Date : 2024-03-01 , DOI: 10.1130/g51658.1
Andreas Petersson 1, 2 , Tod Waight 1 , Anthony I.S. Kemp 3 , Martin. J. Whitehouse 2 , John W. Valley 4
Affiliation  

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.

中文翻译:

芬诺斯堪地盾的始太古代大陆核以及与北大西洋克拉通的联系

大陆地壳的形成是稳定克拉通岩石圈的重要一步。然而,这些最初的地壳核通常要么被回收破坏,要么被较年轻的岩石掩埋。在芬诺斯坎迪亚地盾中,最古老的岩石约为 3.5 Ga,但约。3.7 Ga 继承的锆石和碎屑锆石表明存在较古老的、未暴露的地壳基底。我们提供了来自芬兰三大河流碎屑锆石的 U-Pb、O 和 Hf 同位素数据,以及来自芬兰中部太古代 Suomujärvi 和 Pudasjärvi 杂岩的先前测年岩石的锆石 O 和 Hf 同位素数据。综合起来,这些数据表明存在一个先前未识别的大约。芬诺斯坎迪亚地盾中的 3.75 Ga 地壳核。这增加了全球太古代地体中发现的始太古代核的数量不断增加,凸显了此类核在促进大陆地壳生长方面的重要性。芬诺斯坎迪亚核的同位素特征与格陵兰岛同等年龄的岩石相关,这与芬诺斯坎迪亚和北大西洋克拉通共同的太太古代演化一致。
更新日期:2024-03-02
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