Abstract
Paleoarchean rocks of the tonalite-trondhjemite-granodiorite (TTG) series require a basaltic source region more enriched in K, LILE, Th and LREE than the low-K tholeiites typical of Archean supracrustal sequences. Most TTG of the Pilbara Craton, in northwestern Australia, formed between 3.5 and 3.42 Ga through infracrustal melting of a source older than 3.5 Ga. Basaltic to andesitic rocks of the 3.51 Ga Coucal Formation, at the base of the Pilbara Supergroup, are amongst the only well-preserved remnants of pre-3.5 Ga supracrustal material on Earth, and may have formed a large proportion of pre-3.5 Ga Pilbara crust. These rocks are significantly enriched in K, LILE, Th and LREE compared to post-3.5 Ga Paleoarchean basalts and andesites, and form a compositionally suitable source for TTG. Enrichment in these basalts was not the result of crustal assimilation but was inherited from a mantle source that was less depleted than modern MORB-source and was enriched in recycled crustal components. We suggest that the formation of Paleoarchean TTG and of their voluminous mafic source regions reflects both a primitive stage in the thermal and compositional evolution of the mantle and a significant prehistory of crustal recycling. Crown
| Original language | English |
|---|---|
| Pages (from-to) | 298-306 |
| Number of pages | 9 |
| Journal | Earth and Planetary Science Letters |
| Volume | 281 |
| Issue number | 3-4 |
| DOIs | |
| Publication status | Published - May 15 2009 |
| Externally published | Yes |
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Keywords
- crustal evolution
- enriched basalt
- infracrustal melting
- Paleoarchean
- source regions
- tonalite-trondhjemite-granodiorite (TTG)
ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
Cite this
Formation of Paleoarchean continental crust through infracrustal melting of enriched basalt. / Smithies, R. H.; Champion, D. C.; Van Kranendonk, Martin.
In: Earth and Planetary Science Letters, Vol. 281, No. 3-4, 15.05.2009, p. 298-306.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Formation of Paleoarchean continental crust through infracrustal melting of enriched basalt
AU - Smithies, R. H.
AU - Champion, D. C.
AU - Van Kranendonk, Martin
PY - 2009/5/15
Y1 - 2009/5/15
N2 - Paleoarchean rocks of the tonalite-trondhjemite-granodiorite (TTG) series require a basaltic source region more enriched in K, LILE, Th and LREE than the low-K tholeiites typical of Archean supracrustal sequences. Most TTG of the Pilbara Craton, in northwestern Australia, formed between 3.5 and 3.42 Ga through infracrustal melting of a source older than 3.5 Ga. Basaltic to andesitic rocks of the 3.51 Ga Coucal Formation, at the base of the Pilbara Supergroup, are amongst the only well-preserved remnants of pre-3.5 Ga supracrustal material on Earth, and may have formed a large proportion of pre-3.5 Ga Pilbara crust. These rocks are significantly enriched in K, LILE, Th and LREE compared to post-3.5 Ga Paleoarchean basalts and andesites, and form a compositionally suitable source for TTG. Enrichment in these basalts was not the result of crustal assimilation but was inherited from a mantle source that was less depleted than modern MORB-source and was enriched in recycled crustal components. We suggest that the formation of Paleoarchean TTG and of their voluminous mafic source regions reflects both a primitive stage in the thermal and compositional evolution of the mantle and a significant prehistory of crustal recycling. Crown
AB - Paleoarchean rocks of the tonalite-trondhjemite-granodiorite (TTG) series require a basaltic source region more enriched in K, LILE, Th and LREE than the low-K tholeiites typical of Archean supracrustal sequences. Most TTG of the Pilbara Craton, in northwestern Australia, formed between 3.5 and 3.42 Ga through infracrustal melting of a source older than 3.5 Ga. Basaltic to andesitic rocks of the 3.51 Ga Coucal Formation, at the base of the Pilbara Supergroup, are amongst the only well-preserved remnants of pre-3.5 Ga supracrustal material on Earth, and may have formed a large proportion of pre-3.5 Ga Pilbara crust. These rocks are significantly enriched in K, LILE, Th and LREE compared to post-3.5 Ga Paleoarchean basalts and andesites, and form a compositionally suitable source for TTG. Enrichment in these basalts was not the result of crustal assimilation but was inherited from a mantle source that was less depleted than modern MORB-source and was enriched in recycled crustal components. We suggest that the formation of Paleoarchean TTG and of their voluminous mafic source regions reflects both a primitive stage in the thermal and compositional evolution of the mantle and a significant prehistory of crustal recycling. Crown
KW - crustal evolution
KW - enriched basalt
KW - infracrustal melting
KW - Paleoarchean
KW - source regions
KW - tonalite-trondhjemite-granodiorite (TTG)
UR - http://www.scopus.com/inward/record.url?scp=64549123422&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=64549123422&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2009.03.003
DO - 10.1016/j.epsl.2009.03.003
M3 - Article
AN - SCOPUS:64549123422
VL - 281
SP - 298
EP - 306
JO - Earth and Planetary Sciences Letters
JF - Earth and Planetary Sciences Letters
SN - 0012-821X
IS - 3-4
ER -