Luenha picrites, Central Mozambique – Messengers from a mantle plume source of Karoo continental flood basalts?

Julkaisun otsikon käännös: Luenhan pikriitit keskisestä Mosambikista - Viestintuojia Karoon laakiobasalttien vaippapluumilähteestä?

Tutkimustuotos: ArtikkelijulkaisuArtikkeliTieteellinenvertaisarvioitu

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We present geochemical and isotopic (Nd, Sr) data for a picrite lava suite from the Luenha River and adjacent areas in Mozambique. The Luenha picrites represent a previously unknown type of picrites related to the Karoo large igneous province (LIP) and are distinguished by their notably low TiO2 contents (0.3-1.0 wt%) and coupling of high Nb/Y with low Zr/Y and Sm/Yb. Relatively high CaO and low Zn/Fe point to a peridotitic mantle source. Contamination-sensitive incompatible element ratios show that one lava flow is likely to be uncontaminated by the crust and its composition suggests a mantle source with primitive mantle-like incompatible element ratios and mildly depleted isotopic ratios (initial Sr-87/Sr-86 = 0.7041 and epsilon(Nd) = +1.4 at 180 Ma). The primary melts of the Luenha picrites had MgO contents in the range of 13-21 wt%. Our preferred estimate for a primary melt composition (MgO = 18 wt%) resembles experimental melts of fertile mantle peridotite at 3-4 GPa and indicates liquidus temperature of 1445-1582 degrees C. Geochemical similarities suggest the Luenha picrites were generated from the same overall primitive mantle-like reservoir that produced the main volume of Karoo flood basalts in the Karoo, Kalahari, and Zambezi basins, whereas the previously identified enriched and depleted (upper) mantle sources of Karoo picrite suites (Mwenezi, Antarctica) were subordinate sources for flood basalts. We propose that the Luenha picrites record melting of a hot, chemically primitive mantle plume source that may have been rooted in the sub-African large low shear velocity province boundary and that such a source might have been the most significant magma source in the Karoo LIP. (C) 2019 The Author(s). Published by Elsevier B.V.

Alkuperäiskielienglanti
Artikkeli105152
LehtiLithos
Vuosikerta346-347
Sivumäärä16
ISSN0024-4937
DOI - pysyväislinkit
TilaJulkaistu - 15 marraskuuta 2019
OKM-julkaisutyyppiA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä, vertaisarvioitu

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  • 1171 Geotieteet

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@article{a923ba908c984fdfbab695d5ed4f946e,
title = "Luenha picrites, Central Mozambique – Messengers from a mantle plume source of Karoo continental flood basalts?",
abstract = "We present geochemical and isotopic (Nd, Sr) data for a picrite lava suite from the Luenha River and adjacent areas in Mozambique. The Luenha picrites represent a previously unknown type of picrites related to the Karoo large igneous province (LIP) and are distinguished by their notably low TiO2 contents (0.3-1.0 wt{\%}) and coupling of high Nb/Y with low Zr/Y and Sm/Yb. Relatively high CaO and low Zn/Fe point to a peridotitic mantle source. Contamination-sensitive incompatible element ratios show that one lava flow is likely to be uncontaminated by the crust and its composition suggests a mantle source with primitive mantle-like incompatible element ratios and mildly depleted isotopic ratios (initial Sr-87/Sr-86 = 0.7041 and epsilon(Nd) = +1.4 at 180 Ma). The primary melts of the Luenha picrites had MgO contents in the range of 13-21 wt{\%}. Our preferred estimate for a primary melt composition (MgO = 18 wt{\%}) resembles experimental melts of fertile mantle peridotite at 3-4 GPa and indicates liquidus temperature of 1445-1582 degrees C. Geochemical similarities suggest the Luenha picrites were generated from the same overall primitive mantle-like reservoir that produced the main volume of Karoo flood basalts in the Karoo, Kalahari, and Zambezi basins, whereas the previously identified enriched and depleted (upper) mantle sources of Karoo picrite suites (Mwenezi, Antarctica) were subordinate sources for flood basalts. We propose that the Luenha picrites record melting of a hot, chemically primitive mantle plume source that may have been rooted in the sub-African large low shear velocity province boundary and that such a source might have been the most significant magma source in the Karoo LIP. (C) 2019 The Author(s). Published by Elsevier B.V.",
keywords = "1171 Geosciences, Picrite, Flood basalt, Mantle source, Large igneous province, Mantle plume, DRONNING-MAUD-LAND, LARGE IGNEOUS PROVINCE, TRACE-ELEMENT COMPOSITION, PERIDOTITE SOURCES, MELT INCLUSIONS, DEPLETED MORB, OLIVINE, ANTARCTICA, MAGMAS, LITHOSPHERE, Picrite, Flood basalt, Mantle source, Large igneous province, Mantle plume, DRONNING-MAUD-LAND, LARGE IGNEOUS PROVINCE, TRACE-ELEMENT COMPOSITION, PERIDOTITE SOURCES, MELT INCLUSIONS, DEPLETED MORB, OLIVINE, ANTARCTICA, MAGMAS, LITHOSPHERE",
author = "Turunen, {Sanni T.} and Luttinen, {Arto V.} and Heinonen, {Jussi S.} and Jamal, {Da{\'u}d L.}",
year = "2019",
month = "11",
day = "15",
doi = "10.1016/j.lithos.2019.105152",
language = "English",
volume = "346-347",
journal = "Lithos",
issn = "0024-4937",
publisher = "Elsevier Scientific Publ. Co",

}

Luenha picrites, Central Mozambique – Messengers from a mantle plume source of Karoo continental flood basalts? / Turunen, Sanni T.; Luttinen, Arto V.; Heinonen, Jussi S.; Jamal, Daúd L.

julkaisussa: Lithos, Vuosikerta 346-347, 105152, 15.11.2019.

Tutkimustuotos: ArtikkelijulkaisuArtikkeliTieteellinenvertaisarvioitu

TY - JOUR

T1 - Luenha picrites, Central Mozambique – Messengers from a mantle plume source of Karoo continental flood basalts?

AU - Turunen, Sanni T.

AU - Luttinen, Arto V.

AU - Heinonen, Jussi S.

AU - Jamal, Daúd L.

PY - 2019/11/15

Y1 - 2019/11/15

N2 - We present geochemical and isotopic (Nd, Sr) data for a picrite lava suite from the Luenha River and adjacent areas in Mozambique. The Luenha picrites represent a previously unknown type of picrites related to the Karoo large igneous province (LIP) and are distinguished by their notably low TiO2 contents (0.3-1.0 wt%) and coupling of high Nb/Y with low Zr/Y and Sm/Yb. Relatively high CaO and low Zn/Fe point to a peridotitic mantle source. Contamination-sensitive incompatible element ratios show that one lava flow is likely to be uncontaminated by the crust and its composition suggests a mantle source with primitive mantle-like incompatible element ratios and mildly depleted isotopic ratios (initial Sr-87/Sr-86 = 0.7041 and epsilon(Nd) = +1.4 at 180 Ma). The primary melts of the Luenha picrites had MgO contents in the range of 13-21 wt%. Our preferred estimate for a primary melt composition (MgO = 18 wt%) resembles experimental melts of fertile mantle peridotite at 3-4 GPa and indicates liquidus temperature of 1445-1582 degrees C. Geochemical similarities suggest the Luenha picrites were generated from the same overall primitive mantle-like reservoir that produced the main volume of Karoo flood basalts in the Karoo, Kalahari, and Zambezi basins, whereas the previously identified enriched and depleted (upper) mantle sources of Karoo picrite suites (Mwenezi, Antarctica) were subordinate sources for flood basalts. We propose that the Luenha picrites record melting of a hot, chemically primitive mantle plume source that may have been rooted in the sub-African large low shear velocity province boundary and that such a source might have been the most significant magma source in the Karoo LIP. (C) 2019 The Author(s). Published by Elsevier B.V.

AB - We present geochemical and isotopic (Nd, Sr) data for a picrite lava suite from the Luenha River and adjacent areas in Mozambique. The Luenha picrites represent a previously unknown type of picrites related to the Karoo large igneous province (LIP) and are distinguished by their notably low TiO2 contents (0.3-1.0 wt%) and coupling of high Nb/Y with low Zr/Y and Sm/Yb. Relatively high CaO and low Zn/Fe point to a peridotitic mantle source. Contamination-sensitive incompatible element ratios show that one lava flow is likely to be uncontaminated by the crust and its composition suggests a mantle source with primitive mantle-like incompatible element ratios and mildly depleted isotopic ratios (initial Sr-87/Sr-86 = 0.7041 and epsilon(Nd) = +1.4 at 180 Ma). The primary melts of the Luenha picrites had MgO contents in the range of 13-21 wt%. Our preferred estimate for a primary melt composition (MgO = 18 wt%) resembles experimental melts of fertile mantle peridotite at 3-4 GPa and indicates liquidus temperature of 1445-1582 degrees C. Geochemical similarities suggest the Luenha picrites were generated from the same overall primitive mantle-like reservoir that produced the main volume of Karoo flood basalts in the Karoo, Kalahari, and Zambezi basins, whereas the previously identified enriched and depleted (upper) mantle sources of Karoo picrite suites (Mwenezi, Antarctica) were subordinate sources for flood basalts. We propose that the Luenha picrites record melting of a hot, chemically primitive mantle plume source that may have been rooted in the sub-African large low shear velocity province boundary and that such a source might have been the most significant magma source in the Karoo LIP. (C) 2019 The Author(s). Published by Elsevier B.V.

KW - 1171 Geosciences

KW - Picrite

KW - Flood basalt

KW - Mantle source

KW - Large igneous province

KW - Mantle plume

KW - DRONNING-MAUD-LAND

KW - LARGE IGNEOUS PROVINCE

KW - TRACE-ELEMENT COMPOSITION

KW - PERIDOTITE SOURCES

KW - MELT INCLUSIONS

KW - DEPLETED MORB

KW - OLIVINE

KW - ANTARCTICA

KW - MAGMAS

KW - LITHOSPHERE

KW - Picrite

KW - Flood basalt

KW - Mantle source

KW - Large igneous province

KW - Mantle plume

KW - DRONNING-MAUD-LAND

KW - LARGE IGNEOUS PROVINCE

KW - TRACE-ELEMENT COMPOSITION

KW - PERIDOTITE SOURCES

KW - MELT INCLUSIONS

KW - DEPLETED MORB

KW - OLIVINE

KW - ANTARCTICA

KW - MAGMAS

KW - LITHOSPHERE

U2 - 10.1016/j.lithos.2019.105152

DO - 10.1016/j.lithos.2019.105152

M3 - Article

VL - 346-347

JO - Lithos

JF - Lithos

SN - 0024-4937

M1 - 105152

ER -