Depleted Basaltic Lavas from the Proto-Iceland Plume, Central East Greenland
New geochemical and isotopic data are presented for volumetrically minor, depleted low-Ti basalts that occur in the Plateau Basalt succession of central East Greenland (CEG), formed during the initial stages of opening of the North Atlantic at 55 Ma. The basalts have mid-ocean ridge basalt (MORB)-li...
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fthighwire:oai:open-archive.highwire.org:petrology:53/8/1569 2023-05-15T16:03:44+02:00 Depleted Basaltic Lavas from the Proto-Iceland Plume, Central East Greenland Waight, Tod E. Baker, Joel A. 2012-08-01 00:00:00.0 text/html http://petrology.oxfordjournals.org/cgi/content/short/53/8/1569 https://doi.org/10.1093/petrology/egs026 en eng Oxford University Press http://petrology.oxfordjournals.org/cgi/content/short/53/8/1569 http://dx.doi.org/10.1093/petrology/egs026 Copyright (C) 2012, Oxford University Press Original Papers TEXT 2012 fthighwire https://doi.org/10.1093/petrology/egs026 2013-05-28T09:18:22Z New geochemical and isotopic data are presented for volumetrically minor, depleted low-Ti basalts that occur in the Plateau Basalt succession of central East Greenland (CEG), formed during the initial stages of opening of the North Atlantic at 55 Ma. The basalts have mid-ocean ridge basalt (MORB)-like geochemistry (e.g. depleted light rare earth elements) and are distinct from the high-Ti lavas that dominate the sequence. Rare earth element geochemistry implies derivation from a source more depleted than the typical MORB source, and suggests polybaric melting and contributions from both spinel- and garnet-facies mantle. The low-Ti basalts have Sr–Nd–Pb–Hf isotopic characteristics that are similar to those of depleted magmas from Iceland (e.g. Theistareykir) and adjacent ridges (Kolbeinsey and Reykjanes) and distinct from global MORB (e.g. negative Δ207Pb, and Hf and Nd isotope compositions that plot above the mantle reference line). Isotope and trace element data indicate the involvement of two depleted source components. One component has isotopic compositions similar to other depleted components identified in the North Atlantic and has high Rb/Zr and Ba/Nb. The second is isotopically less depleted with lower Rb/Zr and Ba/Nb. Small degrees of crustal contamination (< 1%) by both amphibolitic and granulitic crust result in relatively large changes in isotopic composition ( c . 1% lower for 206Pb/204Pb and 0·1% higher for 87Sr/86Sr depending on the contaminant). Negative ΔNb suggests a MORB affinity for the low-Ti magmas; however, they are distinguished from global normal (N)-MORB on the basis of vertical deviations from the Northern Hemisphere Reference Line (negative Δ207Pb and positive Δ208Pb), and relative enrichments in Ba, Sr and Pb. The isotopic compositions of the low-Ti CEG basalts suggest correlation with modern depleted components beneath Iceland and adjacent ridges, considered to be derived from upper mantle sources polluted by the Iceland plume. However, small positive Pb peaks when normalized to ... Text East Greenland Greenland Iceland Kolbeinsey North Atlantic HighWire Press (Stanford University) Greenland Reykjanes ENVELOPE(-22.250,-22.250,65.467,65.467) Kolbeinsey ENVELOPE(-18.687,-18.687,67.149,67.149) Journal of Petrology 53 8 1569 1596 |
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HighWire Press (Stanford University) |
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language |
English |
topic |
Original Papers |
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Original Papers Waight, Tod E. Baker, Joel A. Depleted Basaltic Lavas from the Proto-Iceland Plume, Central East Greenland |
topic_facet |
Original Papers |
description |
New geochemical and isotopic data are presented for volumetrically minor, depleted low-Ti basalts that occur in the Plateau Basalt succession of central East Greenland (CEG), formed during the initial stages of opening of the North Atlantic at 55 Ma. The basalts have mid-ocean ridge basalt (MORB)-like geochemistry (e.g. depleted light rare earth elements) and are distinct from the high-Ti lavas that dominate the sequence. Rare earth element geochemistry implies derivation from a source more depleted than the typical MORB source, and suggests polybaric melting and contributions from both spinel- and garnet-facies mantle. The low-Ti basalts have Sr–Nd–Pb–Hf isotopic characteristics that are similar to those of depleted magmas from Iceland (e.g. Theistareykir) and adjacent ridges (Kolbeinsey and Reykjanes) and distinct from global MORB (e.g. negative Δ207Pb, and Hf and Nd isotope compositions that plot above the mantle reference line). Isotope and trace element data indicate the involvement of two depleted source components. One component has isotopic compositions similar to other depleted components identified in the North Atlantic and has high Rb/Zr and Ba/Nb. The second is isotopically less depleted with lower Rb/Zr and Ba/Nb. Small degrees of crustal contamination (< 1%) by both amphibolitic and granulitic crust result in relatively large changes in isotopic composition ( c . 1% lower for 206Pb/204Pb and 0·1% higher for 87Sr/86Sr depending on the contaminant). Negative ΔNb suggests a MORB affinity for the low-Ti magmas; however, they are distinguished from global normal (N)-MORB on the basis of vertical deviations from the Northern Hemisphere Reference Line (negative Δ207Pb and positive Δ208Pb), and relative enrichments in Ba, Sr and Pb. The isotopic compositions of the low-Ti CEG basalts suggest correlation with modern depleted components beneath Iceland and adjacent ridges, considered to be derived from upper mantle sources polluted by the Iceland plume. However, small positive Pb peaks when normalized to ... |
format |
Text |
author |
Waight, Tod E. Baker, Joel A. |
author_facet |
Waight, Tod E. Baker, Joel A. |
author_sort |
Waight, Tod E. |
title |
Depleted Basaltic Lavas from the Proto-Iceland Plume, Central East Greenland |
title_short |
Depleted Basaltic Lavas from the Proto-Iceland Plume, Central East Greenland |
title_full |
Depleted Basaltic Lavas from the Proto-Iceland Plume, Central East Greenland |
title_fullStr |
Depleted Basaltic Lavas from the Proto-Iceland Plume, Central East Greenland |
title_full_unstemmed |
Depleted Basaltic Lavas from the Proto-Iceland Plume, Central East Greenland |
title_sort |
depleted basaltic lavas from the proto-iceland plume, central east greenland |
publisher |
Oxford University Press |
publishDate |
2012 |
url |
http://petrology.oxfordjournals.org/cgi/content/short/53/8/1569 https://doi.org/10.1093/petrology/egs026 |
long_lat |
ENVELOPE(-22.250,-22.250,65.467,65.467) ENVELOPE(-18.687,-18.687,67.149,67.149) |
geographic |
Greenland Reykjanes Kolbeinsey |
geographic_facet |
Greenland Reykjanes Kolbeinsey |
genre |
East Greenland Greenland Iceland Kolbeinsey North Atlantic |
genre_facet |
East Greenland Greenland Iceland Kolbeinsey North Atlantic |
op_relation |
http://petrology.oxfordjournals.org/cgi/content/short/53/8/1569 http://dx.doi.org/10.1093/petrology/egs026 |
op_rights |
Copyright (C) 2012, Oxford University Press |
op_doi |
https://doi.org/10.1093/petrology/egs026 |
container_title |
Journal of Petrology |
container_volume |
53 |
container_issue |
8 |
container_start_page |
1569 |
op_container_end_page |
1596 |
_version_ |
1766399423116476416 |