This assignment exhibits the period since Earth has formed until boundary conditions and tectonics started to stabilize. This period is called Precambrian and consists the 7/8 of Earth’s history. Precambrian lasts 3,9 Ga and is separated into three Eons, Hadean, Archean and Proterozoic with respect to time occurrence.
Earth loses heat through time due to gradually decrease in decay of radiogenic isotopes which are dispersed into the core, mantle and continental crust. Therefore, Earth composition and tectonics distinctly change. Tectonics generally change from vertical patterns to horizontal and the continental crust forms until the end of the Precambrian to the 82% of the overall crust, covering Earth now. Moreover, different movements of Supercontinents which fragmented, dispersed and collided where studied through geological, paleomagnetic and paleoclimatic studies.
Inhaltsverzeichnis (Table of Contents)
- ABSTRACT
- INTRODUCTION
- First Cratons
- PRECAMBRIAN HEAT FLOW
- HADEAN EON 4,5 - 3,9 GA
- EARTH'S OLDEST ROCKS STUDIES
- TTGs Studies
- Hadean detrital Zircon
- HADEAN TECTONIC MODELS
- TTGs
- Zircon:
- ARCHEAN EON 3,9 – 2,5 GA
- GENERAL CHARACTERISTICS OF CRATONIC MANTLE LITHOSPHERE
- GENERAL GEOLOGY OF ARCHEAN CRATONS
- Greenstones.
- High-grade gneiss terrains.
- FORMATION OF THE ARCHEAN MANTLE LITHOSPHERE
- FORMATION OF THE ARCHEAN CRUST
- Dome and Keel Tectonics
- ARCHEAN – PROTEROZOIC BOUNDARY
- PROTEROZOIC EON 2,5 - 0,6 GA
- GENERAL GEOLOGY OF PROTEROZOIC CRATONS
- PROTEROZOIC PLATE TECTONICS
- SUPERCONTINENTAL CYCLE
- LATE ARCHEAN - EARLY PROTEROZOIC SUPERCONTINENTS
- LATE PROTEROZOIC SUPERCONTINENTS
- SUMMARY
- BIBLIOGRAPHY
- REFERENCES CITED
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This assignment focuses on the period from the formation of Earth until the stabilization of boundary conditions and tectonics, known as the Precambrian. The text aims to describe the development of Earth's crust and tectonic processes during this period, which encompasses approximately 7/8 of Earth's history.- The formation and evolution of the Earth's continental crust during the Precambrian.
- The changes in Earth's heat flow and its influence on tectonic processes.
- The development of cratons and their role in the stabilization of the continental lithosphere.
- The different tectonic models proposed for the Hadean and Archean Eons.
- The supercontinental cycles and the formation and breakup of supercontinents during the Precambrian.
Zusammenfassung der Kapitel (Chapter Summaries)
This assignment focuses on the period from the formation of Earth until the stabilization of boundary conditions and tectonics, known as the Precambrian. The text aims to describe the development of Earth's crust and tectonic processes during this period, which encompasses approximately 7/8 of Earth's history. The text begins by discussing the formation of the first cratons, which mark the transition from the early, hot Magma Ocean stage to a state where crustal preservation became possible. The assignment explores the Precambrian heat flow and its impact on tectonic processes, highlighting the gradual decrease in heat flow due to the decay of radiogenic isotopes. The text then delves into the Hadean Eon, examining the oldest rocks and the tectonic models proposed for this period. The assignment discusses the formation and characteristics of the Archean mantle lithosphere and crust, emphasizing the formation of greenstones and high-grade gneiss terrains. The text also explores the transition between the Archean and Proterozoic Eons, including the Proterozoic plate tectonics and the supercontinental cycles. The assignment focuses on the formation and breakup of supercontinents during the Precambrian, providing insights into the geological history of the Earth during this crucial period.Schlüsselwörter (Keywords)
The assignment focuses on Precambrian tectonics, exploring the formation and evolution of the Earth's crust, the development of cratons, the impact of heat flow on tectonic processes, and the supercontinental cycles. Key concepts include the Hadean, Archean, and Proterozoic Eons, TTGs, zircon, greenstones, high-grade gneiss terrains, dome and keel tectonics, and supercontinent formation and breakup. The assignment sheds light on the geological processes that shaped the Earth's surface during the Precambrian period.
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- Anastasia Kokkinou (Author), 2016, Precambrian Tectonics. Tectonics throughout the Hadean and Archean Eon, Munich, GRIN Verlag, https://www.grin.com/document/417008
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