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Archean sedimentary systems and crustal evolutionCurrent knowledge of preserved Archean sedimentary rocks suggests that they accumulated in at least three major depositional settings. These are represented generally by sedimentary units: (1) in early Archean, pre-3.0 Ga old greenstone belts, (2) on late Archean sialic cratons, and (3) in late Archean, post-3.0 Ga old greenstone belts. Research suggests that the Archean was characterized by at least two distinctive and largely diachronous styles of crustal evolution. Thick, stable early Archean simatic platforms, perhaps analogous to modern oceanic islands formed over hot spots, underwent a single cycle of cratonization to form stable continental blocks in the early Archean. Later formed Archean continents show a two stage evolution. The initial stage is reflected in the existence of older sialic material, perhaps representing incompletely cratonized areas or microcontinents of as yet unknown origin. During the second stage, late Archean greenstone belts, perhaps analogous to modern magmatic arcs or back arc basins, developed upon or adjacent to these older sialic blocks. The formation of this generation of Archean continents was largely complete by the end of the Archean. These results suggest that Archean greenstone belts may represent a considerable range of sedimentological and tectonic settings.
Document ID
19850024769
Document Type
Conference Paper
Authors
Lowe, D. R. (Louisiana State Univ. Baton Rouge, LA, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1985
Publication Information
Publication: Lunar and Planetary Inst. Workshop on the Early Earth: The Interval from Accretion to the Older Archean
Subject Category
LUNAR AND PLANETARY EXPLORATION
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19850024749Analytic PrimaryWorkshop on the Early Earth: The Interval from Accretion to the Older Archean