In contrast to modern-day plate tectonics, studying Archean geodynamics presents a unique challenge, as currently there is no agreement upon a paradigm concerning the global geodynamics and lithosphere tectonics pre-1000 million years. The limited amount of geological and geophysical data available contributes significantly to the lack of a widely accepted paradigm. “What happened during Earth’s “dark age” (the first 1000 million years)?” is one of the 10 questions defining 21st century Earth sciences. The aim of this project is: To develop a self-consistent model of lithospheric dynamics in the Archean Eon.
There remains considerable controversy regarding the behavior of the lithosphere of the Earth during the first 2 billion years of its history. The planet was undoubtedly hotter than present day and different dynamic processes are likely to have operated than are represented by well-documented modern Plate Tectonics. The outstanding issues are; (i) What tectonic regime was driving evolution of continental lithosphere during the Archean Eon: vertical or horizontal tectonic? (ii) What was the nature of the transition between pre-plate tectonics to present day tectonics? (iii) How are vertical and horizontal tectonic regimes expressed and recorded in the geological record in terms of structure, magmatisim and mineralization?
The geodynamic controls on early Earth evolution remain a controversial and thus unresolved barrier in furthering our understanding of the evolution of the Earth. The lack of a widely accepted paradigm of global geodynamics and lithosphere tectonics for the early Earth, such as exists for modern-day plate tectonics, is limiting progress toward better understanding Archean geodynamics. It is important to note that a growing suite of observations and analytical data can now be employed for the validation of existing and new models that are developed.
To overcome these limitations, this project will introduce a novel approach to understanding the tectonics of the early continental lithosphere. A state of the art fully coupled 2D and 3D thermo-mechanical-petrological numerical model will be used1. Special emphasis will be placed upon quantitative testing of existing geodynamic concepts developed for the Archean using both global and regional scale fully coupled numerical models. The advantage of this approach is twofold: (1) testing a variety of concepts with the same thermodynamic numerical approach will give comparative results that (2) will proved an atlas of large scale processes validated by geological record in terms of the cooling history of the Earth, which leads to stabilization of cratons and the establishment of well defined plate tectonics in Proterozoic. Besides the insights on the Archean continental deformation dynamics, this project’s ambition is to provide solid link between tectonic processes, magmatisim and mineralization widely present in the Archean Eon.
- Taras Gerya, ETH-Zurich, Switzerland
- Katia Vogt, Utrecht University, Netherlands