Ahmadi, P.

Babazadeh, S.

Braschi, E.

Cai, Y.

Coltorti, M.

Conticelli, S.

Fioretti, A. M.

Ghorbani, M. R.

Giacomoni, P. P.

Kuritani, T.

English

Florence Research

Geophysical Research AbstractsVol. 19, EGU2017-11578-1, 2017EGU General Assembly 2017© Author(s) 2017. CC Attribution 3.0 License.Slab-derived melt involvement in petrogenesis of the high-Nb basalts andmagnesian andesites-dacites from NE IranParham Ahmadi (1), Mohammad Reza Ghorbani (1), Massimo Coltorti (2), Takeshi Kuritani (3), Yue Cai (4),Anna Maria Fioretti (5), Eleonora Braschi (6), Pier Paolo Giacomoni (2), Shahrouz Babazadeh (1), SandroConticelli (6,7)(1) Department of Geology, Tarbiat Modares University, Tehran 114115-175, Iran, (2) Department of Earth Sciences, FerraraUniversity, Via Saragat 1, 44100 Ferrara, Italy, (3) Department of Earh and Planetary Sciences, Graduage School of Science,Hokkaido University, (4) Lamont Doherty Earth Observatory at the Columbia University, 61 Route 9W, Palisades NY 10964,USA, (5) CNR, Istituto di Geoscienze e Georisorse, sezione di Padova, Corso Garibaldi 37, I-35137 Padova, Italy, (6) CNR,Istituto di Geoscienze e Georisorse, sezione di Firenze, Via Giorgio La Pira, 4,I-50121, Firenze, Italy, (7) Dipartimento diScienze della Terra, Università degli Studi di Firenze, Via Giorgio La Pira, 4,I-50121, Firenze, ItalyAbstractTertiary volcanic rocks in NW Firoozeh region, also known as Meshkan triangular structural unit, represent anepisode of Tertiary post-collisional magmatism in NE Iran. The volcanic suite is made of Magnesian andesitesto dacites associated with some high-Nb basalts. Despite a rather restricted range of emplacement age, variablefrom 24.1 to 21.7 Ma obtained on the basis of 40Ar-39Ar dating. Major and trace element data show that Firoozehvolcanic rocks were derived from two distinct parental magmas. The dominant high magnesian magmatic seriesconstitutes a wide spectrum of volcanic rocks from andesite to dacite. The magnesian andesites-dacites aresubalkaline and characterized by rather high MgO, Ni, Cr and Sr/Y ratio. High Sr/Y ratio of the magnesianandesites-dacites as well as their Sr-Nd isotopic composition support the notion that the magnesian andesiteswere originated by interaction of slab derived melts with overlying mantle wedge. Fractional crystallization ofan amphibole and plagioclase mineral assemblage is found responsible for evolutionary path form the magnesianandesite to more evolved rocks. In contrast to the sabalkaline magnesian andesites- dacites, the high Nb basaltsare sodic alkaline rocks and show silica-undersaturated degree. The high-Nb basalts are enriched in Nb, and awide range of incompatible trace elements that include LILE, LREE. Almost identical Sr-Nd isotopic compositionof the magnesian andesites-dacites and high-Nb basalts imply that the two magmatic series has probably shareda common mantle source. Generation of parental magmas of the two magmatic series are attributed to theasthenospheric upwelling and subsequent partial melting of mantle metasomatized by slab-derived melts.Key words: slab melt, High-Nb basalt, 40Ar/39Ar, High-Mg andesiteView publication stats

Slab-derived melt involvement in petrogenesis of the high-Nb basalts and magnesian andesites-dacites from NE Iran

https://flore.unifi.it/bitstream/2158/1122936/1/2017-EGU_Ahmadi%2balii_11578-1.pdf

Slab-derived melt involvement in petrogenesis of the high-Nb basalts and magnesian andesites-dacites from NE Iran

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