Please use this identifier to cite or link to this item:
https://hdl.handle.net/2440/137800
Citations | ||
Scopus | Web of Science® | Altmetric |
---|---|---|
?
|
?
|
Type: | Journal article |
Title: | A detective duo of apatite and zircon geochronology for East Avalonia, Johnston Complex, Wales |
Author: | Clarke, A. Kirkland, C. Glorie, S. |
Citation: | Journal of the Geological Society, 2023; 180(3):jgs2022-178-1-jgs2022-178-14 |
Publisher: | Geological Society |
Issue Date: | 2023 |
ISSN: | 0016-7649 2041-479X |
Statement of Responsibility: | Anthony J.I. Clarke, Christopher L. Kirkland, Stijn Glorie |
Abstract: | The Johnston Complex represents a rare inlier of the Neoproterozoic basement of southern Britain and offers a window into the tectonomagmatic regime of East Avalonia during the assembly of Gondwana. This work presents in-situ zircon (U-Pb, Lu-Hf), apatite (U-Pb), and trace element chemistry for both minerals from the Complex. Zircon and apatite yield a coeval crystallisation age of 570 ± 3 Ma, and a minor antecrystic zircon core component is identified at 615 ± 11 Ma. Zircon Lu-Hf data imply a broadly chondritic source, comparable to Nd data from East Avalonia, and TDM 2 model ages of ca. 1.5 Ga indicate source extraction during the Mesoproterozoic. Zircon trace element chemistry is consistent with an ensialic calcalkaline continental arc setting and demonstrates that magmatism was ongoing prior to terrane dispersal at 570 Ma. Apatite trace element chemistry implies a sedimentary component within the melt consistent with voluminous S-type granite production during the formation of Gondwana. The similarity of ɛHf and geochemistry between both zircon age populations suggest derivation from a uniform source that did not undergo significant modification between 615 – 570 Ma. Time-constrained apatite-zircon chemistry addresses complexities in dating S-type granitoids (zircon inheritance) and permits inferences on post-magmatic thermal histories. |
Keywords: | Neoproterozoic; U-Pb; Lu-Hf; geochemistry; Avalonia; Gondwana; southern Britain |
Description: | Published online: March 30, 2023 |
Rights: | © 2023 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0/). Published by The Geological Society of London. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics |
DOI: | 10.1144/jgs2022-178 |
Grant ID: | http://purl.org/au-research/grants/arc/DP200101881 |
Published version: | http://dx.doi.org/10.1144/jgs2022-178 |
Appears in Collections: | Geology & Geophysics publications |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
hdl_137800.pdf | Published version | 5.69 MB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.