Trace element partitioning between mantle wedge peridotite and hydrous MgO-rich melt
Magmas erupted at convergent margins consist of components from both mantle wedge and subducted slab. In an effort to quantify the relative contributions of these sources, we have determined 19 trace element partition coefficients (D values) for orthopyroxene and clinopyroxene, in equilibrium with s...
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ftuloxford:oai:ora.ox.ac.uk:uuid:9dcc4941-88ff-46f9-bd4f-e7979149b454 2023-05-15T18:23:33+02:00 Trace element partitioning between mantle wedge peridotite and hydrous MgO-rich melt McDade, P Blundy, J Wood, B 2016-07-29 https://ora.ox.ac.uk/objects/uuid:9dcc4941-88ff-46f9-bd4f-e7979149b454 eng eng https://ora.ox.ac.uk/objects/uuid:9dcc4941-88ff-46f9-bd4f-e7979149b454 info:eu-repo/semantics/embargoedAccess Journal article 2016 ftuloxford 2022-06-28T20:19:34Z Magmas erupted at convergent margins consist of components from both mantle wedge and subducted slab. In an effort to quantify the relative contributions of these sources, we have determined 19 trace element partition coefficients (D values) for orthopyroxene and clinopyroxene, in equilibrium with spinel and hydrous high-MgO melt under conditions appropriate to melting in the mantle wedge, i.e., 1.3 GPa, 1245 °C, and ∫o2 of NNO + 1. All trace elements are more incompatible in clinopyroxene during hydrous melting than during anhydrous melting of fertile and depleted peridotite. Orthopyroxene D values are relatively insensitive to pressure, temperature, and phase composition. The new D values are used to calculate the trace-element composition of the mantle wedge, which produced primitive South Sandwich Islands and St. Vincent (Lesser Antilles) arc basalts. Both sources correspond to previously depleted mantle that has been enriched in LILEs and LREEs by slab-derived fluids. In the case of the South Sandwich Islands, the calculated source is in very close agreement with dredged fore-arc lherzolites. Our partitioning data confirm that hydrous melting of wedge peridotite itself cannot produce the characteristic enrichments of LILEs over REEs and HFSEs. Our estimates of the slab component in South Sandwich Islands and St. Vincent are consistent with estimates from other arcs, derived by alternative methods. Article in Journal/Newspaper South Sandwich Islands ORA - Oxford University Research Archive Sandwich Islands South Sandwich Islands |
institution |
Open Polar |
collection |
ORA - Oxford University Research Archive |
op_collection_id |
ftuloxford |
language |
English |
description |
Magmas erupted at convergent margins consist of components from both mantle wedge and subducted slab. In an effort to quantify the relative contributions of these sources, we have determined 19 trace element partition coefficients (D values) for orthopyroxene and clinopyroxene, in equilibrium with spinel and hydrous high-MgO melt under conditions appropriate to melting in the mantle wedge, i.e., 1.3 GPa, 1245 °C, and ∫o2 of NNO + 1. All trace elements are more incompatible in clinopyroxene during hydrous melting than during anhydrous melting of fertile and depleted peridotite. Orthopyroxene D values are relatively insensitive to pressure, temperature, and phase composition. The new D values are used to calculate the trace-element composition of the mantle wedge, which produced primitive South Sandwich Islands and St. Vincent (Lesser Antilles) arc basalts. Both sources correspond to previously depleted mantle that has been enriched in LILEs and LREEs by slab-derived fluids. In the case of the South Sandwich Islands, the calculated source is in very close agreement with dredged fore-arc lherzolites. Our partitioning data confirm that hydrous melting of wedge peridotite itself cannot produce the characteristic enrichments of LILEs over REEs and HFSEs. Our estimates of the slab component in South Sandwich Islands and St. Vincent are consistent with estimates from other arcs, derived by alternative methods. |
format |
Article in Journal/Newspaper |
author |
McDade, P Blundy, J Wood, B |
spellingShingle |
McDade, P Blundy, J Wood, B Trace element partitioning between mantle wedge peridotite and hydrous MgO-rich melt |
author_facet |
McDade, P Blundy, J Wood, B |
author_sort |
McDade, P |
title |
Trace element partitioning between mantle wedge peridotite and hydrous MgO-rich melt |
title_short |
Trace element partitioning between mantle wedge peridotite and hydrous MgO-rich melt |
title_full |
Trace element partitioning between mantle wedge peridotite and hydrous MgO-rich melt |
title_fullStr |
Trace element partitioning between mantle wedge peridotite and hydrous MgO-rich melt |
title_full_unstemmed |
Trace element partitioning between mantle wedge peridotite and hydrous MgO-rich melt |
title_sort |
trace element partitioning between mantle wedge peridotite and hydrous mgo-rich melt |
publishDate |
2016 |
url |
https://ora.ox.ac.uk/objects/uuid:9dcc4941-88ff-46f9-bd4f-e7979149b454 |
geographic |
Sandwich Islands South Sandwich Islands |
geographic_facet |
Sandwich Islands South Sandwich Islands |
genre |
South Sandwich Islands |
genre_facet |
South Sandwich Islands |
op_relation |
https://ora.ox.ac.uk/objects/uuid:9dcc4941-88ff-46f9-bd4f-e7979149b454 |
op_rights |
info:eu-repo/semantics/embargoedAccess |
_version_ |
1766203567065006080 |