Lu-Hf isotope system of Archean granitoids in the Karelia and its implication for regional exploration

Abstract. The Karelian craton is one of the critical minerals exploration target in Europe as it shares similarities with the most mineralized Archean cratons in the world i.e., the Yilgarn and Superior cratons, and a lot of studies have been carried out in this region to understand the mineral syst...

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Bibliographic Details
Main Author: Adegbe, C. (Christopher)
Format: Master Thesis
Language:English
Published: University of Oulu 2023
Subjects:
Online Access:http://jultika.oulu.fi/Record/nbnfioulu-202306302792
Description
Summary:Abstract. The Karelian craton is one of the critical minerals exploration target in Europe as it shares similarities with the most mineralized Archean cratons in the world i.e., the Yilgarn and Superior cratons, and a lot of studies have been carried out in this region to understand the mineral systems and potentials. The wide adoption of the Mineral Systems Approach (MSA) has encouraged the application of isotope systems to metallogeny and regional exploration. The knowledge of the geologic history and evolution of geological terrains and their paleo lithospheric architectures may reveal a component of their mineral systems, including possible metal sources, pathways of fluids, and processes responsible for mineralization. Isotope systems have been used to constrain the paleo lithospheric structure in Archean cratons. They have also been used in generating regional-scale isotopic maps to identify metallogenic blocks for decades. More and more isotopic data are being generated from different studies especially for the Sm-Nd isotope system, and more recently, for the Lu-Hf system, and the availability of more data and relevant software has now made it easier to construct isotopic maps from regional to continental scales. Abundant whole rock Sm-Nd data of Archean granitoids have been published for the Karelian craton but not much data has been generated for the Lu-Hf isotope system of zircon from Archean granitiods. Compared to bulk rock Sm-Nd isotope, zircon Lu-Hf may be less affected by later stage metamorphic events. In this study, in-situ U-Pb and Lu-Hf analyses of zircons of Archean granitoid samples from the Western Karelian province have been obtained, and the data is compared with already existing Sm-Nd isotope data and bulk zircon U-Pb age data to ascertain co-relation or disparities and possible reasons, and to investigate the geochronology, Archean tectonics and lithospheric structure of the different terrains/blocks in western Karelia, and to link the occurrence of metallogenic belts and lithospheric ...