The Hadean Crust: Evidence from >4 Ga Zircons

2009/04/27 by T. Mark Harrison · 10 citations
Earth and Planetary Sciences · Physics and Astronomy · #Geological and Geochemical Analysis #Astro and Planetary Science #High-pressure geophysics and materials

paper · doi:10.1146/annurev.earth.031208.100151

Abstract

A review of continental growth models leaves open the possibilities that Earth during the Hadean Eon (∼4.5–4.0 Ga) was characterized by massive early crust or essentially none at all. Without support from the rock record, our understanding of pre-Archean continental crust must largely come from investigating Hadean detrital zircons. We know that these ancient zircons yield relatively low crystallization temperatures and some are enriched in heavy oxygen, contain inclusions similar to modern crustal processes, and show evidence of silicate differentiation at ∼4.5 Ga. These observations are interpreted to reflect an early terrestrial hydrosphere, early felsic crust in which granitoids were produced and later weathered under high water activity conditions, and even the possible existence of plate boundary interactions—in strong contrast to the traditional view of an uninhabitable, hellish world. Possible scenarios are explored with a view to reconciling this growing but fragmentary record with our knowledge of conditions then extant in the inner solar system.

Citations

• Pb diffusion in zircon
• Chemical mass transfer in magmatic processes IV. A revised and internally consistent thermodynamic model for the interpolation and extrapolation of liquid-solid equilibria in magmatic systems at elevated temperatures and pressures
• Zircon megacrysts from kimberlite: oxygen isotope variability among mantle melts
• The Lu–Hf and Sm–Nd isotopic composition of CHUR: Constraints from unequilibrated chondrites and implications for the bulk composition of terrestrial planets
• New thermodynamic models and revised calibrations for the Ti-in-zircon and Zr-in-rutile thermometers

Cited by

• Deep Mantle–Atmosphere Coupling and Carbonaceous Bombardment: Options for Biomolecule Formation on an Oxidized Early Earth
• Hadean geodynamics and the nature of early continental crust
• Magma Oceans in the Inner Solar System
• Plate Tectonics and the Archean Earth
• Plate tectonic–like cycles since the Hadean: Initiated or inherited?
• We don't know when plate tectonics began
• Initiation and Evolution of Plate Tectonics on Earth: Theories and Observations
• Earth's Continental Lithosphere Through Time
• Planetary Felsic Crust Formation at Shallow Depth
• Onset of plate tectonics by the Eoarchean

Related

• Contemporaneous mobile- and stagnant-lid tectonics on the Hadean Earth
• The continental record and the generation of continental crust
• Plate tectonic–like cycles since the Hadean: Initiated or inherited?
• Toward a myth-free geodynamic history of Earth and its neighbors
• Subduction Origin of the Nb Anomaly in Earth’s Oldest Continents