Petrogenesis of Plio-Quaternary post-collisional ultrapotassic volcanism in NW of Marand, NW Iran

Ahmadzadeh, G.; Jahangiri, Ahmad; Lentz, David D.R.; Mojtahedi, M

doi:10.1016/j.jseaes.2010.02.008

Cited by 55 publications

(30 citation statements)

References 51 publications

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“…Simplified and modified after Babakhani, Lesquyer & Rico (1990) represented by the UDMA and AMB, is attributed to a sequence of episodes starting with direct subduction (e.g. Berberian et al 1982;Shahabpour, 2007, among others), slab break-off (Ghasemi & Talbot, 2006) and slab roll-back (Ahmadzadeh et al 2010). Consequently, varied petrogenetic models have been suggested from continental arc settings (Berberian & King, 1981;J.…”

Section: Outline Of Regional Geologymentioning

confidence: 99%

Post-collisional polycyclic plutonism from the Zagros hinterland: the Shaivar Dagh plutonic complex, Alborz belt, Iran

et al. 2011

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-The petrological and geochronological study of the Cenozoic Shaivar Dagh composite intrusion in the Alborz Mountain belt (NW Iran) reveals important clues to decipher complex relations between magmatic and tectonic processes in the central sectors of the Tethyan (Alpine-Himalayan) orogenic belt. This pluton is formed by intrusion at different times of two main magmatic cycles. The older (Cycle 1) is formed by calc-alkaline silicic rocks, which range in composition from diorites to granodiorites and biotite granites, with abundant mafic microgranular enclaves. The younger cycle (Cycle 2) is formed by K-rich monzodiorite and monzonite of marked shoshonitic affinity. The latter form the larger volumes of the exposed plutonic rocks in the studied complex. Zircon geochronology (laser ablation ICP-MS analyses) gives a concordia age of 30.8 ± 2.1 Ma for the calc-alkaline rocks (Cycle 1) and a range from 23.3 ± 0.5 to 25.1 ± 0.9 Ma for the shoshonitic association (Cycle 2). Major and trace element relations strongly support distinct origins for each magmatic cycle. Rocks of Cycle 1 have all the characteristic features of active continental margins. Shoshonitic rocks (Cycle 2) define two continuous fractionation trends: one departing from a K-rich basaltic composition and the other from an intermediate, K-rich composition. A metasomatized-mantle origin for the two shoshonitic series of Cycle 2 is proposed on the basis of comparisons with experimental data. The origin of the calc-alkaline series is more controversial but it can be attributed to processes in the suprasubduction mantle wedge related to the incorporation of subducted mélanges in the form of silicic cold plumes. A time sequence can be established for the processes responsible of the generation of the two magmatic cycles: first a calc-alkaline cycle typical of active continental margins, and second a K-rich cycle formed by monzonites and monzodiorites. This sequence precludes the younger potassic magmas as precursors of the older calc-alkaline series. By contrast, the older calc-alkaline magmas may represent the metasomatic agents that modified the mantle wedge during the last stages of subduction and cooked a fertile mantle region for late potassic magmatism after continental collision.

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Section: Outline Of Regional Geologymentioning

confidence: 99%

Post-collisional polycyclic plutonism from the Zagros hinterland: the Shaivar Dagh plutonic complex, Alborz belt, Iran

et al. 2011

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“…The northern part of UDMA has experienced calc-alkaline magmatism during the Eocene period and alkaline and ultrapotassic magmatism during the Quaternary period (Ahmadzadeh et al 2010). Preliminary research indicates that calc-alkaline magmatism during the Eocene is related to subduction of Neo-Tethys oceanic crust beneath CIM.…”

Section: Geodynamic Implicationsmentioning

confidence: 93%

“…As a result of extensional transtensional regime, local volcanic activities occurred along the main dextral faults, like the north-Tabriz dextral fault. The volcanic activity along the north Tabriz dextral fault is represented by the Late Miocene and ultrapotassic and alkaline mafic magmas with adakitic signatures during the PlioceneQuaternary (Ahmadzadeh et al 2010).…”

Section: Geodynamic Implicationsmentioning

confidence: 99%

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Quaternary post-collision alkaline volcanism NW of Ahar (NW Iran): geochemical constraints of fractional crystallization process

Dabiri¹,

Emami²,

Mollaei³

et al. 2011

Geologica Carpathica

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Major and trace elements and Sr-Nd isotopic data are presented for the Quaternary alkaline volcanism NW of Ahar (NW Iran). The exposed rocks mainly consist of alkali basalts, trachybasalts, basaltic trachyandesites and trachyandesites. Alkali basalts and trachybasalts display microlithic porphyritic texture with phenocrysts of olivine, clinopyroxene, and plagioclase in microlithic groundmass. In the more evolved rocks (basaltic trachyandesites and trachyandesites), amphibole and biotite have appeared. Sr ratio and high MgO, Ni and Cr contents indicate that they were generated from relatively primitive magmas. Ba, Cr and La/Sm ratios versus Rb suggest that fractional crystallization of alkali basalts could have played a significant role in the formation of evolved rocks. Assimilation and fractional crystallization modelling, as well as Rb/Zr, Th/Yb and Ta/Yb ratios clearly indicate that crustal contamination accompanied by the fractional crystallization played an important role in petrogenesis of the trachyandesites. The small compositional differences between magma types, isotopic composition, mineralogy and nonlinear trends on Harker diagrams also indicate that magma mixing was not an essential process in the evolution of the Ahar magmas. Petrogenetic modelling has been used to constrain sources. Trace element ratio plots and REE modelling indicate that the alkali basalts were generated from a spinel-peridotite source via small degrees (~2.5%) of fractional melting.

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“…They characterized with significant enrichment in LILE and LREE and depletion in highfield-strength elements. So, the metasomatized lithospheric mantle composed of garnet lherzulite and high fugacity of CO 2 /H 2 O ratio played a significant role in their genesis (Ahmadzadeh, 2010 andKhezerlu, 2008).…”

Section: Alborz-arasbaran-lesser Caucasus Belt (Aalcb)mentioning

confidence: 99%

Petrogenesis and Tectono-Magmatic Setting of Meso-Cenozoic Magmatism in Azerbaijan Province, Northwestern Iran

Jamali¹,

Yaghubpur²,

Mehrabi³

et al. 2012

Petrology - New Perspectives and Applications

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Petrogenesis of Plio-Quaternary post-collisional ultrapotassic volcanism in NW of Marand, NW Iran

Cited by 55 publications

References 51 publications

Post-collisional polycyclic plutonism from the Zagros hinterland: the Shaivar Dagh plutonic complex, Alborz belt, Iran

Post-collisional polycyclic plutonism from the Zagros hinterland: the Shaivar Dagh plutonic complex, Alborz belt, Iran

Quaternary post-collision alkaline volcanism NW of Ahar (NW Iran): geochemical constraints of fractional crystallization process

Petrogenesis and Tectono-Magmatic Setting of Meso-Cenozoic Magmatism in Azerbaijan Province, Northwestern Iran

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