Abstract

Oceanic mafic volcanic rocks preserve unique information regarding the nature and evolution of tectonic plates. However, constraining their age is commonly challenging because of their lack of datable minerals and high degrees of alteration. We present in situ laser ablation–inductively coupled plasma–mass spectrometry U-Pb dating of calcite phases in altered basalts in a Paleozoic subduction complex (eastern Australia). Calcite enclosed in amygdules and filled in fractures yielded two distinctive ages with contrasting geochemical signatures. These results, combined with new biostratigraphic and whole-rock geochemical data, suggest that oceanic islands formed in the Panthalassa Ocean at about 365 million years ago, accreted to eastern Gondwana at about 330 million years ago, and underwent brittle deformation at about 305 million years ago. Calcite U-Pb geochronology is valuable to help constrain minimum formation ages of volcanic rocks and their deformation history, ultimately improving ability to unravel the geological record of accretionary complexes, and more generally ancient underwater volcanic systems.

The formation and tectonic evolution of mafic oceanic crust can be determined through dating of calcite amygdules using U-Pb geochronology as well as geochemistry and biostratigraphic observations, according to a study of the New England Orogen, Australia.

Details

Title
Paleozoic ocean plate stratigraphy unraveled by calcite U-Pb dating of basalt and biostratigraphy
Author
Andjić Goran 1   VIAFID ORCID Logo  ; Zhou Renjie 2   VIAFID ORCID Logo  ; Buchs, David M 3 ; Aitchison, Jonathan C 2   VIAFID ORCID Logo  ; Zhao, Jianxin 2   VIAFID ORCID Logo 

 The University of Queensland, School of Earth and Environmental Sciences, St Lucia, Australia (GRID:grid.1003.2) (ISNI:0000 0000 9320 7537); Utrecht University, Department of Earth Sciences, Utrecht, The Netherlands (GRID:grid.5477.1) (ISNI:0000000120346234) 
 The University of Queensland, School of Earth and Environmental Sciences, St Lucia, Australia (GRID:grid.1003.2) (ISNI:0000 0000 9320 7537) 
 Cardiff University, School of Earth and Environmental Sciences, Cardiff, UK (GRID:grid.5600.3) (ISNI:0000 0001 0807 5670) 
Publication year
2022
Publication date
Dec 2022
Publisher
Nature Publishing Group
e-ISSN
26624435
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2663154749
Copyright
© The Author(s) 2022. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.