Enrichments of the mantle sources beneath the Southern Volcanic Zone (Andes) by fluids and melts derived from abraded upper continental crust
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Enrichments of the mantle sources beneath the Southern Volcanic Zone (Andes) by fluids and melts derived from abraded upper continental crust. / Holm, Paul Martin; Søager, Nina; Dyhr, Charlotte Thorup; Nielsen, Mia Rohde.
In: Contributions to Mineralogy and Petrology, Vol. 167, 1004, 2014.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Enrichments of the mantle sources beneath the Southern Volcanic Zone (Andes) by fluids and melts derived from abraded upper continental crust
AU - Holm, Paul Martin
AU - Søager, Nina
AU - Dyhr, Charlotte Thorup
AU - Nielsen, Mia Rohde
PY - 2014
Y1 - 2014
N2 - Mafic basaltic-andesitic volcanic rocks from the Andean Southern Volcanic Zone (SVZ) exhibit a northward increase in crustal components in primitive arc magmas from the Central through the Transitional and Northern SVZ segments. New elemental and Sr–Nd-high-precision Pb isotope data from the Quaternary arc volcanic centres of Maipo (NSVZ) and Infernillo and Laguna del Maule (TSVZ) are argued to reflect mainly their mantle source and its melting. For the C-T-NSVZ, we identify two types of source enrichment: one, represented by Antuco in CSVZ, but also present northward along the arc, was dominated by fluids which enriched a pre-metasomatic South Atlantic depleted MORB mantle type asthenosphere. The second enrichment was by melts having the characteristics of upper continental crust (UCC), distinctly different from Chile trench sediments. We suggest that granitic rocks entered the source mantle by means of subduction erosion in response to the northward increasingly strong coupling of the converging plates. Both types of enrichment had the same Pb isotope composition in the TSVZ with no significant component derived from the subducting oceanic crust. Pb–Sr–Nd isotopes indicate a major crustal compositional change at the southern end of the NSVZ. Modelling suggests addition of around 2 % UCC for Infernillo and 5 % for Maipo
AB - Mafic basaltic-andesitic volcanic rocks from the Andean Southern Volcanic Zone (SVZ) exhibit a northward increase in crustal components in primitive arc magmas from the Central through the Transitional and Northern SVZ segments. New elemental and Sr–Nd-high-precision Pb isotope data from the Quaternary arc volcanic centres of Maipo (NSVZ) and Infernillo and Laguna del Maule (TSVZ) are argued to reflect mainly their mantle source and its melting. For the C-T-NSVZ, we identify two types of source enrichment: one, represented by Antuco in CSVZ, but also present northward along the arc, was dominated by fluids which enriched a pre-metasomatic South Atlantic depleted MORB mantle type asthenosphere. The second enrichment was by melts having the characteristics of upper continental crust (UCC), distinctly different from Chile trench sediments. We suggest that granitic rocks entered the source mantle by means of subduction erosion in response to the northward increasingly strong coupling of the converging plates. Both types of enrichment had the same Pb isotope composition in the TSVZ with no significant component derived from the subducting oceanic crust. Pb–Sr–Nd isotopes indicate a major crustal compositional change at the southern end of the NSVZ. Modelling suggests addition of around 2 % UCC for Infernillo and 5 % for Maipo
KW - Faculty of Science
KW - Andean volcanism
KW - Southern Volcanic Zone
KW - Basaltic andesite
KW - Pb-Sr-Nd isotopes
KW - Mantle melting
KW - Subduction erosion
U2 - 10.1007/s00410-014-1004-8
DO - 10.1007/s00410-014-1004-8
M3 - Journal article
VL - 167
JO - Contributions to Mineralogy and Petrology
JF - Contributions to Mineralogy and Petrology
SN - 0010-7999
M1 - 1004
ER -
ID: 93952688