Growth and accretion of continental crust

Inferences based on Laurentia

Kent C. Condie*

*Corresponding author for this work

Research output: Contribution to journalArticle

66 Citations (Scopus)

Abstract

Nd isotopic data and U-Pb zircon ages from Laurentia (North America and the Baltic Shield) indicate that continental growth (extraction from the mantle) and accretion (collision of arcs and microcontinents) have been episodic with maxima at 2.7, 1.9, 1.8 and 1.7 Ga ago and a major period of accretion at ∼ 1.9 Ga ago. In general, accretion follows mantle extraction by <100 Ma. Archean and Early Proterozoic continental growth rates are 0.5-0.7 km3 a-1, whereas Late Proterozoic and Phanerozoic rates are 0.2-0.3 km3 a-1. Laurentia reached 40% of its present volume by the end of the Archean and 75% by 1.6 Ga ago. Reworking of continental crust does not become significant until after 1.2 Ga. Calculated worldwide continental growth rates for the Late Archean, Early Proterozoic and Late Proterozoic-Phanerozoic are ∼3, ∼1.5 and ∼ 1.1km3 a-1, respectively. These rates are in good agreement with growth rates predicted by assuming that continental growth rate is proportional to the decrease in radiogenic heat production in the Earth with time.

Original languageEnglish
Pages (from-to)183-194
Number of pages12
JournalChemical Geology
Volume83
Issue number3-4
DOIs
Publication statusPublished - 25 Jun 1990
Externally publishedYes

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