The mantle source of thermal plumes: Trace and minor elements in olivine and major oxides of primitive liquids (and why the olivine compositions don't matter)
We estimate the mantle source compositions for mantle plumes and, by implication, Earth's lower mantle by: (1) measuring trace (e.g, Sc, V, Cu) and minor (e.g., Ca, Mn, Ni) element concentrations of high-forsterite olivine grains from several plume localities, (2) estimating the parent liquid c...
Published in: | American Mineralogist |
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Main Authors: | , , , , , |
Format: | Report |
Language: | English |
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MINERALOGICAL SOC AMER
2018
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Online Access: | http://ir.gig.ac.cn/handle/344008/39219 https://doi.org/10.2138/am-2018-6192 |
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ftchacadscgigcas:oai:ir.gig.ac.cn:344008/39219 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) |
op_collection_id |
ftchacadscgigcas |
language |
English |
topic |
Geochemistry & Geophysics Mineralogy Olivine plumes mantle composition lower mantle Baffin Island Hawaii Deccan Emeishan EAST PACIFIC RISE MIDOCEAN RIDGE BASALTS OCEAN ISLAND BASALTS TRANSITION ZONE PARTITION-COEFFICIENTS MELTING EXPERIMENTS PICRITIC BASALTS PERIDOTITE KLB-1 DEPLETED MANTLE OXIDATION-STATE |
spellingShingle |
Geochemistry & Geophysics Mineralogy Olivine plumes mantle composition lower mantle Baffin Island Hawaii Deccan Emeishan EAST PACIFIC RISE MIDOCEAN RIDGE BASALTS OCEAN ISLAND BASALTS TRANSITION ZONE PARTITION-COEFFICIENTS MELTING EXPERIMENTS PICRITIC BASALTS PERIDOTITE KLB-1 DEPLETED MANTLE OXIDATION-STATE Putirka, Keith Tao, Yan Hari, K. R. Perfit, Michael R. Jackson, Matthew G. Arevalo, Ricardo, Jr. The mantle source of thermal plumes: Trace and minor elements in olivine and major oxides of primitive liquids (and why the olivine compositions don't matter) |
topic_facet |
Geochemistry & Geophysics Mineralogy Olivine plumes mantle composition lower mantle Baffin Island Hawaii Deccan Emeishan EAST PACIFIC RISE MIDOCEAN RIDGE BASALTS OCEAN ISLAND BASALTS TRANSITION ZONE PARTITION-COEFFICIENTS MELTING EXPERIMENTS PICRITIC BASALTS PERIDOTITE KLB-1 DEPLETED MANTLE OXIDATION-STATE |
description |
We estimate the mantle source compositions for mantle plumes and, by implication, Earth's lower mantle by: (1) measuring trace (e.g, Sc, V, Cu) and minor (e.g., Ca, Mn, Ni) element concentrations of high-forsterite olivine grains from several plume localities, (2) estimating the parent liquid compositions from which they crystallized, (3) calculating mantle potential temperatures and degrees of partial melting, and (4) estimating trace element compositions of depleted and enriched mantle sources. Our sample set includes two continental flood basalt provinces (Emeishan and Deccan), a flood basalt that erupted in a continental rift setting (Baffin Island), our type example of a thermal mantle plume (Hawaii), and lavas from the Siqueiros Transform at the East Pacific Rise, which represent the mid-ocean ridge system. We also present olivine (Ol) compositions for peridotite xenoliths from Kilbourne Hole, New Mexico, U.S.A., which are commonly used as primary and secondary analytical standards. We find that trace elements in lava-hosted olivine grains are too far removed from their mantle source to provide anything but greatly hindered views of such. Olivine compositions reflect not only evolving liquid compositions (including partial melting conditions and later fractionation), but also evolving Ol+liq partition coefficients, which mostly increase with decreasing T during crystallization. Mantle compositions, delimited by maximum forsterite contents and estimates of parental magmas (and experimentally determined partition coefficients) indicate that our selected plumes reflect some combination of (1) a depleted mantle source that is quite similar to that obtained by other methods and (2) a variably enriched plume source that is more enriched than current estimates of pyrolite. The enriched plume mantle sources can be explained remarkably well as a mixture of subducted mid-ocean ridge basalt (MORB; Gale et al. 2013) and depleted MORB mantle (DM; Salters and Stracke 2004), with MORB:DMM ratios of 1:5 to 1:4. These ratios are most sensitive to estimates of melt fraction where plume parental magmas are last equilibrated with their mantle source, but are nonetheless consistent across a wide range of chemically very different elements, and estimates of MORB and DM obtained by very different means. Baffin Island is of particular interest. Like prior studies, we verify a high mantle potential temperature (T-p) of 1630 degrees C (compared to T-p = 1320-1420 degrees C for MORB from Cottrell and Kelley 2011 for Ol of Fo(89.3-91.4)). The Baffin source is also within error the same as DM with respect to trace elements, although still isotopically distinct; Baffin appears to be sourced in something that is akin to DMM that lies at the base of the mantle, where plumes acquire their excess heat. Thus while part of our analysis supports the concept of a "slab graveyard" at the bottom of the lower mantle (e.g., Wyession 1996), that cemetery is by no means ubiquitous at the CMB: subducted slabs are either unevenly interred, or efficiently excavated by later upwellings. |
format |
Report |
author |
Putirka, Keith Tao, Yan Hari, K. R. Perfit, Michael R. Jackson, Matthew G. Arevalo, Ricardo, Jr. |
author_facet |
Putirka, Keith Tao, Yan Hari, K. R. Perfit, Michael R. Jackson, Matthew G. Arevalo, Ricardo, Jr. |
author_sort |
Putirka, Keith |
title |
The mantle source of thermal plumes: Trace and minor elements in olivine and major oxides of primitive liquids (and why the olivine compositions don't matter) |
title_short |
The mantle source of thermal plumes: Trace and minor elements in olivine and major oxides of primitive liquids (and why the olivine compositions don't matter) |
title_full |
The mantle source of thermal plumes: Trace and minor elements in olivine and major oxides of primitive liquids (and why the olivine compositions don't matter) |
title_fullStr |
The mantle source of thermal plumes: Trace and minor elements in olivine and major oxides of primitive liquids (and why the olivine compositions don't matter) |
title_full_unstemmed |
The mantle source of thermal plumes: Trace and minor elements in olivine and major oxides of primitive liquids (and why the olivine compositions don't matter) |
title_sort |
mantle source of thermal plumes: trace and minor elements in olivine and major oxides of primitive liquids (and why the olivine compositions don't matter) |
publisher |
MINERALOGICAL SOC AMER |
publishDate |
2018 |
url |
http://ir.gig.ac.cn/handle/344008/39219 https://doi.org/10.2138/am-2018-6192 |
geographic |
Baffin Island Pacific |
geographic_facet |
Baffin Island Pacific |
genre |
Baffin Island Baffin Ocean Island |
genre_facet |
Baffin Island Baffin Ocean Island |
op_relation |
AMERICAN MINERALOGIST http://ir.gig.ac.cn/handle/344008/39219 doi:10.2138/am-2018-6192 |
op_doi |
https://doi.org/10.2138/am-2018-6192 |
container_title |
American Mineralogist |
container_volume |
103 |
container_issue |
8 |
container_start_page |
1253 |
op_container_end_page |
1270 |
_version_ |
1766365766551076864 |
spelling |
ftchacadscgigcas:oai:ir.gig.ac.cn:344008/39219 2023-05-15T15:35:26+02:00 The mantle source of thermal plumes: Trace and minor elements in olivine and major oxides of primitive liquids (and why the olivine compositions don't matter) Putirka, Keith Tao, Yan Hari, K. R. Perfit, Michael R. Jackson, Matthew G. Arevalo, Ricardo, Jr. 2018-08-01 http://ir.gig.ac.cn/handle/344008/39219 https://doi.org/10.2138/am-2018-6192 英语 eng MINERALOGICAL SOC AMER AMERICAN MINERALOGIST http://ir.gig.ac.cn/handle/344008/39219 doi:10.2138/am-2018-6192 Geochemistry & Geophysics Mineralogy Olivine plumes mantle composition lower mantle Baffin Island Hawaii Deccan Emeishan EAST PACIFIC RISE MIDOCEAN RIDGE BASALTS OCEAN ISLAND BASALTS TRANSITION ZONE PARTITION-COEFFICIENTS MELTING EXPERIMENTS PICRITIC BASALTS PERIDOTITE KLB-1 DEPLETED MANTLE OXIDATION-STATE 期刊论文 2018 ftchacadscgigcas https://doi.org/10.2138/am-2018-6192 2020-12-22T07:21:29Z We estimate the mantle source compositions for mantle plumes and, by implication, Earth's lower mantle by: (1) measuring trace (e.g, Sc, V, Cu) and minor (e.g., Ca, Mn, Ni) element concentrations of high-forsterite olivine grains from several plume localities, (2) estimating the parent liquid compositions from which they crystallized, (3) calculating mantle potential temperatures and degrees of partial melting, and (4) estimating trace element compositions of depleted and enriched mantle sources. Our sample set includes two continental flood basalt provinces (Emeishan and Deccan), a flood basalt that erupted in a continental rift setting (Baffin Island), our type example of a thermal mantle plume (Hawaii), and lavas from the Siqueiros Transform at the East Pacific Rise, which represent the mid-ocean ridge system. We also present olivine (Ol) compositions for peridotite xenoliths from Kilbourne Hole, New Mexico, U.S.A., which are commonly used as primary and secondary analytical standards. We find that trace elements in lava-hosted olivine grains are too far removed from their mantle source to provide anything but greatly hindered views of such. Olivine compositions reflect not only evolving liquid compositions (including partial melting conditions and later fractionation), but also evolving Ol+liq partition coefficients, which mostly increase with decreasing T during crystallization. Mantle compositions, delimited by maximum forsterite contents and estimates of parental magmas (and experimentally determined partition coefficients) indicate that our selected plumes reflect some combination of (1) a depleted mantle source that is quite similar to that obtained by other methods and (2) a variably enriched plume source that is more enriched than current estimates of pyrolite. The enriched plume mantle sources can be explained remarkably well as a mixture of subducted mid-ocean ridge basalt (MORB; Gale et al. 2013) and depleted MORB mantle (DM; Salters and Stracke 2004), with MORB:DMM ratios of 1:5 to 1:4. These ratios are most sensitive to estimates of melt fraction where plume parental magmas are last equilibrated with their mantle source, but are nonetheless consistent across a wide range of chemically very different elements, and estimates of MORB and DM obtained by very different means. Baffin Island is of particular interest. Like prior studies, we verify a high mantle potential temperature (T-p) of 1630 degrees C (compared to T-p = 1320-1420 degrees C for MORB from Cottrell and Kelley 2011 for Ol of Fo(89.3-91.4)). The Baffin source is also within error the same as DM with respect to trace elements, although still isotopically distinct; Baffin appears to be sourced in something that is akin to DMM that lies at the base of the mantle, where plumes acquire their excess heat. Thus while part of our analysis supports the concept of a "slab graveyard" at the bottom of the lower mantle (e.g., Wyession 1996), that cemetery is by no means ubiquitous at the CMB: subducted slabs are either unevenly interred, or efficiently excavated by later upwellings. Report Baffin Island Baffin Ocean Island Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) Baffin Island Pacific American Mineralogist 103 8 1253 1270 |