Geochemical evidence for melting of carbonated peridotite on Santa Maria Island, Azores

Beier C, Mata J, Stoeckhert F, Mattielli N, Brandl P, Madureira P, Genske F, Martins S, Madeira J, Haase K (2013)

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2013

Journal

Publisher: Springer Verlag (Germany)

Book Volume: 165

Pages Range: 823-841

Journal Issue: 5

DOI: 10.1007/s00410-012-0837-2

Abstract

The islands of the Azores archipelago emerge from an oceanic plateau built on lithosphere increasing in age with distance from the Mid-Atlantic Ridge from 10 to 45 Ma. Here, we present the first comprehensive major and trace element and Sr-Nd-Pb isotope data from Santa Maria, the easternmost island of the archipelago, along with published data from the other Azores islands situated much closer to the Mid-Atlantic Ridge axis. We can show that the distinctively more variable and more enriched trace element ratios at Santa Maria combined with a relatively small range in Sr-Nd-Pb isotope ratios are the result of low degrees of partial melting of a common Azores mantle plume source underneath thicker lithosphere. This implies that melt extraction processes and melting dynamics may be able to better preserve the trace element mantle source variability underneath thicker lithosphere. These conclusions may apply widely for oceanic melts erupted on relatively thick lithosphere. In addition, lower Ti/Sm and K/La ratios and SiO contents of Santa Maria lavas imply melting of a carbonated peridotite source. Mixing of variable portions of deep small-degree carbonated peridotite melts and shallow volatile-free garnet peridotite could explain the geochemical variability underneath Santa Maria in agreement with the volatile-rich nature of the Azores mantle source. However, Santa Maria is the Azores island where the CO-rich nature of the mantle source is more evident, reflecting a combination of a smaller extent of partial melting and the positioning at the edge of the tilted Azores mantle plume. © 2012 Springer-Verlag Berlin Heidelberg.

Authors with CRIS profile

Involved external institutions

University of Lisbon / Universidade de Lisboa (ULisboa) Portugal (PT) Université libre de Bruxelles (ULB) / Free University of Brussels Belgium (BE) Estrutura de Missão para a Extensão da Plataforma Continental Portugal (PT)

How to cite

APA:

Beier, C., Mata, J., Stoeckhert, F., Mattielli, N., Brandl, P., Madureira, P.,... Haase, K. (2013). Geochemical evidence for melting of carbonated peridotite on Santa Maria Island, Azores. Contributions To Mineralogy and Petrology, 165(5), 823-841. https://dx.doi.org/10.1007/s00410-012-0837-2

MLA:

Beier, Christoph, et al. "Geochemical evidence for melting of carbonated peridotite on Santa Maria Island, Azores." Contributions To Mineralogy and Petrology 165.5 (2013): 823-841.

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