Crustal evolution in the SW part of the Baltic Shield : the Hf isotope evidence | Macquarie University ResearchOnline

Home

List Of Titles

Crustal evolution in the SW part of the Baltic Shield : the Hf isotope evidence

Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.14/26337

21 Visitors

22 Hits

0 Downloads

Title: Crustal evolution in the SW part of the Baltic Shield : the Hf isotope evidence
Related: Journal of petrology, Vol. 43, Issue 9, p.1725-1747
DOI: 10.1093/petrology/43.9.1725
Publisher: Oxford University Press
Date: 2002
Author/Creator: Andersen, T
Author/Creator: Griffin, W. L
Author/Creator: Pearson, N. J
Description: The results of a laser ablation microprobe–inductively coupled plasma mass spectrometry Lu–Hf isotope study of zircons in 0·93–1·67 Ga rocks from south Norway indicate that early Proterozoic protoliths of the Baltic Shield have present-day ¹⁷⁶Hf/¹⁷⁷Hf ≤ 0·28190 [εHf(t) = 5–6], whereas 1·52–1·60 Ga juvenile additions to the continental margin have ¹⁷⁶Hf/¹⁷⁷Hf = 0·2810 [εHf(t) = 12–13]. Mid- to late Proterozoic felsic igneous rocks in the region are characterized by a range of Hf isotopic compositions suggesting mixing of material derived from Palaeoproterozoic crust from the Baltic Shield and/or mid-Proterozoic juvenile crust. New mantle-derived magmas were added to the crust at ~1·48 Ga and in Sveconorwegian time. Late Sveconorwegian granites from the area west of the Oslo Rift have inherited zircons with low ¹⁷⁶Hf/¹⁷⁷Hf (<0·28180), suggesting that a pre-1·7 Ga crustal source contributed to the magmas. The evolution of the continental crust in this region is thus a result of repeated interaction between mantle-derived magmas and mid- to early Proterozoic crustal rocks. The results of this study confirm the presence of early Proterozoic rocks in the deep crust west of the Oslo Rift, and support tectonic models in which the protolith of the western part of south Norway has been part of the Baltic Shield since the early Proterozoic.
Description: 23 page(s)
Subject Keyword: hafnium isotopes
Subject Keyword: Baltic Shield
Subject Keyword: continental crust
Subject Keyword: crustal evolution
Resource Type: journal article
Organisation: Macquarie University. Dept. of Earth and Planetary Sciences
Organisation: Macquarie University. National Key Centre for Geochemical Evolution and Metallogeny of Continents (GEMOC)

Identifier: http://hdl.handle.net/1959.14/26337
Identifier: ISSN:1460-2415
Identifier: mq-rm-2002014874
Language: eng
Reviewed

Macquarie University ResearchOnline

Search

Browse

Highlights

Resources