| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
Assessing Origins of End-Triassic Tholeiites From Eastern North America Using Hafnium Isotopes
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| Autores: |
Elkins, Lynne J.
Meyzen, Christine M.
Callegaro, Sara
Marzoli, Andrea
Bizimis, Michael
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| Data: |
2020-06
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| Ano: |
2020
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| Palavras-chave: |
Basalt
CAMP
Hafnium
Rift
LIP
Isotope
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| Resumo: |
The driving processes responsible for producing the Central Atlantic Magmatic Province, the Large Igneous Province associated with end-Triassic rifting of Pangea, remain largely debated. Because their compositions encompass most of the Central Atlantic basalt spectrum, tholeiites from southern Eastern North America are considered pivotal for identifying magma origins. New(176)Hf/Hf-177 measurements for 201 Ma Eastern North American tholeiites dominantly record a local petrogenetic history. Their epsilon(Hf)ratios, corrected to an emplacement age of 201 Ma (-7.85 to +5.86), form a positive but shallowly sloped array slightly deviating from the terrestrial array on a epsilon(Hf)versus epsilon(Nd)diagram. Comparison of(176)Hf/Hf-177 to other isotope ratios and trace elements helps to rule out several petrogenetic scenarios, particularly mixing of melts from global depleted or enriched mantle components. In contrast, partial melting of subduction-metasomatized mantle can explain the parental magma composition for southern Eastern North America. Such metasomatism likely occurred during Paleozoic subduction around Pangea and may have been dominated by sediment-derived fluid reactions. The observed(176)Hf/Hf-177 versus(143)Nd/Nd-144 array may reflect subsequent assimilation of lower continental crust, perhaps together with limited direct melting of recycled continental crust in the asthenosphere. The proposed recycling scenario does not specifically support or preclude a mantle plume origin for the Central Atlantic Magmatic Province but instead points toward the presence of a distinct local mantle source and crustal assimilation processes during magma transport. Detailed understanding of these local effects is needed in order to more accurately understand the origins of Large Igneous Provinces.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
https://archimer.ifremer.fr/doc/00687/79862/82716.pdf
https://archimer.ifremer.fr/doc/00687/79862/82717.pdf
https://archimer.ifremer.fr/doc/00687/79862/82718.xlsx
DOI:10.1029/2020GC008999
https://archimer.ifremer.fr/doc/00687/79862/
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| Editor: |
Amer Geophysical Union
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| Formato: |
application/pdf
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| Fonte: |
Geochemistry Geophysics Geosystems (1525-2027) (Amer Geophysical Union), 2020-06 , Vol. 21 , N. 6 , P. e2020GC008999
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| Direitos: |
info:eu-repo/semantics/openAccess
restricted use
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