Mechanism of Continental Crustal Growth

M. Stein*, Z. Ben-Avraham

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

3 Scopus citations

Abstract

The continental crust comprising the outmost 20-80 km of the solid surface of the Earth and covering ~ 41% of the Earth's surface area is of great antiquity and contains the record of most of the geological (physical and chemical) evolution of the Earth. The oldest surviving rocks date from more than four billion years ago, a few hundred million years after the formation of the Earth. A major research theme in Earth Sciences is the understanding of the mechanism of continental crust growth. Different models suggested early creation and subsequent recycling of continental crust material or continuous or episodic crustal growth (the "Anderson-Moorbath debate'). This debate is entwined with discussions on the geodynamic-magmatic environment of crustal growth and the role that arcs and/or mantle plumes play in juvenile crustal growth (the "Reymer and Schubert dilemma'). We discuss mantle overturn and accretion models that invoke episodic activity of large mantle plumes and accretion of juvenile mantle material (such as the oceanic plateaus) to the continents (the "MOMO model'), alternative arc-tectonic models, or recent suggestions for continents preservation models. New insights on the earliest history of continental crust and the relation to mantle evolution come from the exciting studies on radiogenic isotopes of Hf in zircons and radiogenic Nd isotopes (e.g. 143Nd and 142Nd, the decay products of 147Sm and the extinct 146Sm) in magmatic rocks.It appears that throughout the past ~ 2.7 Ga major segments of continental crust over the globe were evolved through similar evolution and petrogenetic histories: early formation of thick sequences of basalts in oceanic environment that resemble those of plume-related oceanic plateaus (e.g. the Cretaceous Ontong Java plateau in the Pacific), this phase is followed by a long phase (~250-300 Ma) of arc subducation-related calc-alkaline magmatism (such as the western Pacific arc) that comprise major juvenile addition to the continental crust. After cessation of subduction process, the existing crust and lithospheric mantle evolve through metamorphism and melting that produce calc-alkaline and alkaline granitic magmas that comprise most of the uppermost continental crust. Production of granitic magmas requires water in their sources (e.g. amphibolites). The role of water in shaping the unique structure, composition, and landscape of the outermost Earth is emphasized in the Campbell and Taylor concept of: no water, no granites, no oceans, no continents.

Original languageEnglish
Title of host publicationEvolution of the Earth
PublisherElsevier Inc.
Pages173-199
Number of pages27
Volume9
ISBN (Electronic)9780444538031
ISBN (Print)9780444538024
DOIs
StatePublished - 1 Jan 2015

Keywords

  • Arcs
  • Continental-crust
  • Geochronology
  • Granites
  • Mantle-plumes
  • Radiogenic-isotopes

Fingerprint

Dive into the research topics of 'Mechanism of Continental Crustal Growth'. Together they form a unique fingerprint.

Cite this