Staff directory
Jean-Paul Liégeois
Earth Sciences
Geodynamics and mineral resources
Geodynamics and mineral resources
Publication details
Deevsalar, R., Shinjo, R., Liégeois, J.P., Valizadeh, M.V., Ahmadian, J., Yeganehfar, H., Murata, M. & Neill, I. 2018. ‘Subduction-related mafic to felsic magmatism in the Malayer–Boroujerd plutonic complex, western Iran’. Swiss Journal of Geosciences. DOI: https://doi.org/10.1007/s00015-017-0287-y. I.F. 1.53.
Article in a scientific Journal / Article in a Journal
The Malayer–Boroujerd plutonic complex (MBPC) in western Iran, consists of a portion of a magmatic arc built by the
northeast verging subduction of the Neo-Tethys plate beneath the Central Iranian Microcontinent (CIMC). Middle Jurassicaged
felsic magmatic activity in MBPC is manifested by I-type and S-type granites. The mafic rocks include gabbroic
intrusions and dykes and intermediate rocks are dioritic dykes and minor intrusions, as well as mafic microgranular
enclaves (MMEs). MBPC Jurassic-aged rocks exhibit arc-like geochemical signatures, as they are LILE- and LREEenriched
and HFSE- and HREE-depleted and display negative Nb–Ta anomalies. The gabbro dykes and intrusions originated
from metasomatically enriched garnet-spinel lherzolite [Degree of melting (fmel) * 15%] and exhibit negative Nd
and positive to slightly negative eHf(T) (? 3.0 to - 1.6). The data reveal that evolution of Middle Jurassic magmatism
occurred in two stages: (1) deep mantle-crust interplay zone and (2) the shallow level upper crustal magma chamber. The
geochemical and isotopic data, as well as trace element modeling, indicate the parent magma for the MBPC S-type granites
are products of upper crustal greywacke (fmel: 0.2), while I-type granites formed by partial melting of amphibolitic lower
crust (fmel: 0.25) and mixing with upper crustal greywacke melt in a shallow level magma chamber [Degree of mixing
(fmix): 0.3]. Mixing between andesitic melt leaving behind a refractory dense cumulates during partial crystallization of
mantle-derived magma and lower crustal partial melt most likely produced MMEs (fmix: 0.2). However, enriched and
moderately variable eNd(T) (- 3.21 to - 4.33) and high (87Sr/86Sr)i (0.7085–0.7092) in dioritic intrusions indicate that
these magmas are likely experienced assimilation of upper crustal materials. The interpretations of magmatic activity in the
MBPC is consistent with the role considered for mantle-derived magma as heat and mass supplier for initiation and
evolution of magmatism in continental arc setting, elsewhere.