The strong resilience of the mineral zircon and its ability to host a wealth of isotopic information make it the best deep-time archive of Earth’s continental crust. Zircon is found in most felsic igneous rocks, can be precisely dated and can fingerprint magmatic sources; thus, it has been widely used to document the formation and evolution of continental crust, from pluton- to global-scale. Here, we present a review of major contributions that zircon studies have made in terms of understanding key questions involving the formation of the continents. These include the conditions of continent formation on early Earth, the onset of plate tectonics and subduction, the rate of crustal growth through time and the governing balance of continental addition v. continental loss, and the role of preservation bias in the zircon record.
A compilation used in this study of previously published detrital zircon U-Pb-Hf isotope data are available at http://www.geolsoc.org.uk/SUP18791
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Continent Formation Through Time
The continental crust is our archive of Earth history, and the store of many natural resources; however, many key questions about its formation and evolution remain debated and unresolved:
What processes are involved in the formation, differentiation and evolution of continental crust, and how have these changed throughout Earth history?
How are plate tectonics, the supercontinent cycle and mantle cooling linked with crustal evolution?
What are the rates of generation and destruction of the continental crust through time?
How representative is the preserved geological record?
A range of approaches are used to address these questions, including field-based studies, petrology and geochemistry, geophysical methods, palaeomagnetism, whole-rock and accessory-phase isotope chemistry and geochronology. Case studies range from the Eoarchaean to Phanerozoic, and cover many different cratons and orogenic belts from across the continents.