An experimental study of the partitioning of trace elements between rutile and silicate melt as a function of oxygen fugacity

Autor(es)

Mallmann, Guilherme ^{[1, 2]} ; Fonseca, Raul O. C. ^[3] ; Silva, Adolfo B. ^[4]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Geociencias, BR-05508080 Sao Paulo - Brazil

^[2] Univ Queensland, Sch Earth Sci, Brisbane, Qld 4072 - Australia

^[3] Univ Bonn, Steinmann Inst Geol Mineral & Paleontol, D-53115 Bonn - Germany

^[4] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Anais da Academia Brasileira de Ciências; v. 86, n. 4, p. 1609-1629, DEC 2014.
• Citações Web of Science: 4

Resumo

Subduction zone or arc magmas are known to display a characteristic depletion of High Field Strength Elements (HFSE) relative to other similarly incompatible elements, which can be attributed to the presence of the accessory mineral rutile (TiO2) in the residual slab. Here we show that the partitioning behavior of vanadium between rutile and silicate melt varies from incompatible (similar to 0.1) to compatible (similar to 18) as a function of oxygen fugacity. We also confirm that the HFSE are compatible in rutile, with D(Ta) > D(Nb) >> (D(Hf) >/similar to D(Zr), but that the level of compatibility is strongly dependent on melt composition, with partition coefficients increasing about one order of magnitude with increasing melt polymerization (or decreasing basicity). Our partitioning results also indicate that residual rutile may fractionate U from Th due to the contrasting (over 2 orders of magnitude) partitioning between these two elements. We confirm that, in addition to the HFSE, Cr, Cu, Zn and W are compatible in rutile at all oxygen fugacity conditions. (AU)

• Processo FAPESP: 10/05512-1 - Estudos experimentais de acresção e diferenciação planetária
• Beneficiário: Guilherme Mallmann
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores