Speculations on nature and extent of Archean basement in Labrador as indicated by SR, ND and PB isotopic systematics of proterozoic intrusives
The Sm-Nd and Rb-Sr isotopic compositions of mid to late Proterozoic (approximately 1.6 to 1.1 Ga) massif-type anorthosites and mafic intrusives in the eastern Canadian shield are correlated with geographic location. Complexes in the Grenville province have positive epsilon sub Nd values and initial...
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ftnasantrs:oai:casi.ntrs.nasa.gov:19860019064 2023-05-15T17:13:58+02:00 Speculations on nature and extent of Archean basement in Labrador as indicated by SR, ND and PB isotopic systematics of proterozoic intrusives Wooden, J. L. Emslie, R. F. Ashwal, L. D. Unclassified, Unlimited, Publicly available JAN 1, 1986 application/pdf http://hdl.handle.net/2060/19860019064 unknown Document ID: 19860019064 Accession ID: 86N28536 http://hdl.handle.net/2060/19860019064 No Copyright CASI GEOPHYSICS Workshop on Early Crustal Genesis: The World's Oldest Rocks; p 17-21 1986 ftnasantrs 2016-06-11T22:52:12Z The Sm-Nd and Rb-Sr isotopic compositions of mid to late Proterozoic (approximately 1.6 to 1.1 Ga) massif-type anorthosites and mafic intrusives in the eastern Canadian shield are correlated with geographic location. Complexes in the Grenville province have positive epsilon sub Nd values and initial Sr-87/Sr-86 (I sub Sr) generally less than 0.703, suggesting derivation from depleted mantle. In Labrador, similar complexes close to or northwest of a line roughly corresponding to the Grenville Front have negative epsilon sub Nd values and I sub Sr 0.703. This contrast was intrepreted as reflecting either enriched mantle under the Nain Province, or contamination of the Nain intrusives with older crustal components. Lead isotopic compositions, however, favor the latter. The possibility of using these Proterozoic intrusives as tracers to characterize the nature and extent of older basement types in Labrador is discussed. Other/Unknown Material Nain NASA Technical Reports Server (NTRS) Nain ENVELOPE(-61.695,-61.695,56.542,56.542) |
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NASA Technical Reports Server (NTRS) |
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ftnasantrs |
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topic |
GEOPHYSICS |
spellingShingle |
GEOPHYSICS Wooden, J. L. Emslie, R. F. Ashwal, L. D. Speculations on nature and extent of Archean basement in Labrador as indicated by SR, ND and PB isotopic systematics of proterozoic intrusives |
topic_facet |
GEOPHYSICS |
description |
The Sm-Nd and Rb-Sr isotopic compositions of mid to late Proterozoic (approximately 1.6 to 1.1 Ga) massif-type anorthosites and mafic intrusives in the eastern Canadian shield are correlated with geographic location. Complexes in the Grenville province have positive epsilon sub Nd values and initial Sr-87/Sr-86 (I sub Sr) generally less than 0.703, suggesting derivation from depleted mantle. In Labrador, similar complexes close to or northwest of a line roughly corresponding to the Grenville Front have negative epsilon sub Nd values and I sub Sr 0.703. This contrast was intrepreted as reflecting either enriched mantle under the Nain Province, or contamination of the Nain intrusives with older crustal components. Lead isotopic compositions, however, favor the latter. The possibility of using these Proterozoic intrusives as tracers to characterize the nature and extent of older basement types in Labrador is discussed. |
format |
Other/Unknown Material |
author |
Wooden, J. L. Emslie, R. F. Ashwal, L. D. |
author_facet |
Wooden, J. L. Emslie, R. F. Ashwal, L. D. |
author_sort |
Wooden, J. L. |
title |
Speculations on nature and extent of Archean basement in Labrador as indicated by SR, ND and PB isotopic systematics of proterozoic intrusives |
title_short |
Speculations on nature and extent of Archean basement in Labrador as indicated by SR, ND and PB isotopic systematics of proterozoic intrusives |
title_full |
Speculations on nature and extent of Archean basement in Labrador as indicated by SR, ND and PB isotopic systematics of proterozoic intrusives |
title_fullStr |
Speculations on nature and extent of Archean basement in Labrador as indicated by SR, ND and PB isotopic systematics of proterozoic intrusives |
title_full_unstemmed |
Speculations on nature and extent of Archean basement in Labrador as indicated by SR, ND and PB isotopic systematics of proterozoic intrusives |
title_sort |
speculations on nature and extent of archean basement in labrador as indicated by sr, nd and pb isotopic systematics of proterozoic intrusives |
publishDate |
1986 |
url |
http://hdl.handle.net/2060/19860019064 |
op_coverage |
Unclassified, Unlimited, Publicly available |
long_lat |
ENVELOPE(-61.695,-61.695,56.542,56.542) |
geographic |
Nain |
geographic_facet |
Nain |
genre |
Nain |
genre_facet |
Nain |
op_source |
CASI |
op_relation |
Document ID: 19860019064 Accession ID: 86N28536 http://hdl.handle.net/2060/19860019064 |
op_rights |
No Copyright |
_version_ |
1766071211950866432 |