Regional zircon U-Pb geochronology for the Maniitsoq region, southwest Greenland

Hugo K H Olierook,Bradley J Mcdonald,Pedro Waterton,Michael I H Hartnady,Milo Barham,Agnete Steenfelt,Noreen J Evans,Christopher L Kirkland,Nicholas J Gardiner,Julie A Hollis,Chris Yakymchuk,Kristoffer Szilas

doi:10.1038/s41597-021-00922-x

Abstract

Zircon U-Pb geochronology places high-temperature geological events into temporal context. Here, we present a comprehensive zircon U-Pb geochronology dataset for the Meso- to Neoarchean Maniitsoq region in southwest Greenland, which includes the Akia Terrane, Tuno Terrane, and the intervening Alanngua Complex. The magmatic and metamorphic processes recorded in these terranes straddle a key change-point in early Earth geodynamics. This dataset comprises zircon U-Pb ages for 121 samples, including 46 that are newly dated. A principal crystallization peak occurs across all three terranes at ca. 3000 Ma, with subordinate crystallization age peaks at 3200 Ma (Akia Terrane and Alanngua Complex only), 2720 Ma and 2540 Ma. Metamorphic age peaks occur at 2990 Ma, 2820–2700 Ma, 2670–2600 Ma and 2540 Ma. Except for one sample, all dated metamorphic zircon growth after the Neoarchean occurred in the Alanngua Complex or within 20 km of its boundaries. This U-Pb dataset provides an important resource for addressing Earth Science topics as diverse as crustal evolution, fluid–rock interaction and mineral deposit genesis.

Highlights

Background & SummaryGeochronology aims to establish the timing of geological events using naturally-occurring radioactive isotopes
The U–Pb isotopic system is the benchmark for determining the age of geological materials because, unlike other chronometers, it exploits two independent isotopic decay schemes, allowing open-system behavior to be detected and it permits accurate evaluation of temporal context
The Akia Terrane dominantly comprises rocks with crystallization ages that fall into two distinct age and lithological groupings: (i) a dioritic core formed at ca. 3230–3190 million years ago (Ma), and (ii) voluminous 3070–2970 Ma tonalitic crust[5,6]

Summary

Introduction

Background & SummaryGeochronology aims to establish the timing of geological events using naturally-occurring radioactive isotopes. Due to the numerous questions that can be addressed with zircon geochronology of the Maniitsoq region, there have been a number of papers published on the ages of components in the Akia Terrane and its bordering tectonic belts (including the Tuno Terrane and Alanngua Complex) in the past four decades (see Data Records).

Results

Conclusion