Limits...
How and when plume zonation appeared during the 132 Myr evolution of the Tristan Hotspot.

Hoernle K, Rohde J, Hauff F, Garbe-Schönberg D, Homrighausen S, Werner R, Morgan JP - Nat Commun (2015)

Bottom Line: The origin of this zonation is currently unclear.Recently zonation was found along the last ∼70 Myr of the Tristan-Gough hotspot track.Here we present a model that can explain the temporal evolution and origin of plume zonation for both the Tristan-Gough and Hawaiian hotspots, two end member types of zoned plumes, through processes taking place in the plume sources at the base of the lower mantle.

View Article: PubMed Central - PubMed

Affiliation: 1] GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany [2] CAU Kiel University, Institute of Geosciences, Ludewig-Meyn-Strasse 10, D-24118 Kiel, Germany.

ABSTRACT
Increasingly, spatial geochemical zonation, present as geographically distinct, subparallel trends, is observed along hotspot tracks, such as Hawaii and the Galapagos. The origin of this zonation is currently unclear. Recently zonation was found along the last ∼70 Myr of the Tristan-Gough hotspot track. Here we present new Sr-Nd-Pb-Hf isotope data from the older parts of this hotspot track (Walvis Ridge and Rio Grande Rise) and re-evaluate published data from the Etendeka and Parana flood basalts erupted at the initiation of the hotspot track. We show that only the enriched Gough, but not the less-enriched Tristan, component is present in the earlier (70-132 Ma) history of the hotspot. Here we present a model that can explain the temporal evolution and origin of plume zonation for both the Tristan-Gough and Hawaiian hotspots, two end member types of zoned plumes, through processes taking place in the plume sources at the base of the lower mantle.

No MeSH data available.


Related in: MedlinePlus

Bathymetric map of the South Atlantic Ocean and its margins showing the Tristan-Gough hotspot track.The map shows the Tristan-Gough hotspot track including the ∼132 Myr (ref. 22) old Etendeka and Parana continental flood basalt provinces, the Rio Grand Rise and Walvis Ridge (both within the age range ∼60–115 Ma), the Guyot Province at the southwestern end of the Walvis Ridge containing the Tristan da Cunha and Gough Island groups (∼0–60 Ma)24. Ages for late-stage volcanism are not shown. Age range in italics (87–107 Ma) is estimated using a spatial age progression equation24. Sample locations are denoted by symbols: large symbols this study and small symbols as reported in ref. 13. Source of base map is http://www.geomapapp.org. All sites are from the Deep Sea Drilling Project. The scale bar in the lower right hand corner indicates a distance of ∼500 km.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4525177&req=5

f1: Bathymetric map of the South Atlantic Ocean and its margins showing the Tristan-Gough hotspot track.The map shows the Tristan-Gough hotspot track including the ∼132 Myr (ref. 22) old Etendeka and Parana continental flood basalt provinces, the Rio Grand Rise and Walvis Ridge (both within the age range ∼60–115 Ma), the Guyot Province at the southwestern end of the Walvis Ridge containing the Tristan da Cunha and Gough Island groups (∼0–60 Ma)24. Ages for late-stage volcanism are not shown. Age range in italics (87–107 Ma) is estimated using a spatial age progression equation24. Sample locations are denoted by symbols: large symbols this study and small symbols as reported in ref. 13. Source of base map is http://www.geomapapp.org. All sites are from the Deep Sea Drilling Project. The scale bar in the lower right hand corner indicates a distance of ∼500 km.

Mentions: The Tristan-Gough hotspot track (Fig. 1) represents the classic evolution of a hotspot18 with active volcanic islands at its young end and flood basalt provinces at its older end. It has been termed one of the seven hotspots most likely to be derived from the lowermost mantle from a ‘primary' plume19 with its base currently located at the margin of the African LLSVP2021. The emplacement of a Tristan-Gough plume head at the base of the Gondwana lithosphere caused massive volcanism forming the Parana (eastern South America) and Etendeka (western Africa) flood basalts at ∼132 Ma22 and may have contributed to the breakup of Africa from South America and the formation of the South Atlantic Ocean basin23. As the Atlantic opened, the ridge-centred plume tail formed the Walvis Ridge on the African Plate and the Rio Grande Rise (possibly underlain by a thinned continental block) on the South American Plate. As the South Atlantic mid-ocean ridge drifted westwards away from the plume tail ∼50–60 Ma, the hotspot became intraplate forming the Guyot Province, consisting of separate volcanic tracks leading to the active volcanic islands of Tristan da Cunha and Gough24.


How and when plume zonation appeared during the 132 Myr evolution of the Tristan Hotspot.

Hoernle K, Rohde J, Hauff F, Garbe-Schönberg D, Homrighausen S, Werner R, Morgan JP - Nat Commun (2015)

Bathymetric map of the South Atlantic Ocean and its margins showing the Tristan-Gough hotspot track.The map shows the Tristan-Gough hotspot track including the ∼132 Myr (ref. 22) old Etendeka and Parana continental flood basalt provinces, the Rio Grand Rise and Walvis Ridge (both within the age range ∼60–115 Ma), the Guyot Province at the southwestern end of the Walvis Ridge containing the Tristan da Cunha and Gough Island groups (∼0–60 Ma)24. Ages for late-stage volcanism are not shown. Age range in italics (87–107 Ma) is estimated using a spatial age progression equation24. Sample locations are denoted by symbols: large symbols this study and small symbols as reported in ref. 13. Source of base map is http://www.geomapapp.org. All sites are from the Deep Sea Drilling Project. The scale bar in the lower right hand corner indicates a distance of ∼500 km.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525177&req=5

f1: Bathymetric map of the South Atlantic Ocean and its margins showing the Tristan-Gough hotspot track.The map shows the Tristan-Gough hotspot track including the ∼132 Myr (ref. 22) old Etendeka and Parana continental flood basalt provinces, the Rio Grand Rise and Walvis Ridge (both within the age range ∼60–115 Ma), the Guyot Province at the southwestern end of the Walvis Ridge containing the Tristan da Cunha and Gough Island groups (∼0–60 Ma)24. Ages for late-stage volcanism are not shown. Age range in italics (87–107 Ma) is estimated using a spatial age progression equation24. Sample locations are denoted by symbols: large symbols this study and small symbols as reported in ref. 13. Source of base map is http://www.geomapapp.org. All sites are from the Deep Sea Drilling Project. The scale bar in the lower right hand corner indicates a distance of ∼500 km.
Mentions: The Tristan-Gough hotspot track (Fig. 1) represents the classic evolution of a hotspot18 with active volcanic islands at its young end and flood basalt provinces at its older end. It has been termed one of the seven hotspots most likely to be derived from the lowermost mantle from a ‘primary' plume19 with its base currently located at the margin of the African LLSVP2021. The emplacement of a Tristan-Gough plume head at the base of the Gondwana lithosphere caused massive volcanism forming the Parana (eastern South America) and Etendeka (western Africa) flood basalts at ∼132 Ma22 and may have contributed to the breakup of Africa from South America and the formation of the South Atlantic Ocean basin23. As the Atlantic opened, the ridge-centred plume tail formed the Walvis Ridge on the African Plate and the Rio Grande Rise (possibly underlain by a thinned continental block) on the South American Plate. As the South Atlantic mid-ocean ridge drifted westwards away from the plume tail ∼50–60 Ma, the hotspot became intraplate forming the Guyot Province, consisting of separate volcanic tracks leading to the active volcanic islands of Tristan da Cunha and Gough24.

Bottom Line: The origin of this zonation is currently unclear.Recently zonation was found along the last ∼70 Myr of the Tristan-Gough hotspot track.Here we present a model that can explain the temporal evolution and origin of plume zonation for both the Tristan-Gough and Hawaiian hotspots, two end member types of zoned plumes, through processes taking place in the plume sources at the base of the lower mantle.

View Article: PubMed Central - PubMed

Affiliation: 1] GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany [2] CAU Kiel University, Institute of Geosciences, Ludewig-Meyn-Strasse 10, D-24118 Kiel, Germany.

ABSTRACT
Increasingly, spatial geochemical zonation, present as geographically distinct, subparallel trends, is observed along hotspot tracks, such as Hawaii and the Galapagos. The origin of this zonation is currently unclear. Recently zonation was found along the last ∼70 Myr of the Tristan-Gough hotspot track. Here we present new Sr-Nd-Pb-Hf isotope data from the older parts of this hotspot track (Walvis Ridge and Rio Grande Rise) and re-evaluate published data from the Etendeka and Parana flood basalts erupted at the initiation of the hotspot track. We show that only the enriched Gough, but not the less-enriched Tristan, component is present in the earlier (70-132 Ma) history of the hotspot. Here we present a model that can explain the temporal evolution and origin of plume zonation for both the Tristan-Gough and Hawaiian hotspots, two end member types of zoned plumes, through processes taking place in the plume sources at the base of the lower mantle.

No MeSH data available.


Related in: MedlinePlus