The magmatic record in the Arghash region (northeast Iran) and tectonic implications

Alaminia, Zahra; Karimpour, Mohammad Hassan; Homam, Seyed Massoud; Finger, Friedrich

doi:10.1007/s00531-013-0897-1

Cited by 34 publications

(10 citation statements)

References 33 publications

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“…Back‐arc basin formation was concomitant with faulting, uplift and core complex exhumation in parts of the Iranian plateau (Malekpour‐Alamdari et al, 2017; Moritz et al, 2006; Verdel et al, 2007). Back‐arc plutonism intensified between 105 and 90 Ma, as also suggested by Alaminia et al (2013). Intrusive rocks from this episode have calc‐alkaline characteristics whereas most extrusive rocks have MORB‐like geochemical signatures.…”

Section: Discussionsupporting

confidence: 71%

Neotethyan Subduction Ignited the Iran Arc and Backarc Differently

Moghadam

et al. 2020

JGR Solid Earth

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Most arcs show systematic temporal and spatial variations in magmatism with clear shifts in igneous rock compositions between those of the magmatic front (MF) and those in the backarc (BA). It is unclear if similar magmatic polarity is seen for extensional continental arcs. Herein, we use geochemical and isotopic characteristics coupled with zircon U‐Pb geochronology to identify the different magmatic style of the Iran convergent margin, an extensional system that evolved over 100 Myr. Our new and compiled U‐Pb ages indicate that major magmatic episodes for the NE Iran BA occurred at 110–80, 75–50, 50–35, 35–20, and 15–10 Ma. In contrast to NE Iran BA magmatic episodes, compiled data from MF display two main magmatic episodes at 95–75 and 55–5 Ma, indicating more continuous magmatism for the MF than for the BA. We show that Paleogene Iran serves as a useful example of a continental arc under extension. Our data also suggest that there is not a clear relationship between the subduction velocity of Neotethyan Ocean beneath Iran and magmatic activity in Iran. Our results imply that the isotopic compositions of Iran BA igneous rocks do not directly correspond to the changes in tectonic processes or geodynamics, but other parameters such as the composition of lithosphere and melt source(s) should be considered. In addition, changes in subduction zone dynamics and contractional versus extensional tectonic regimes influenced the composition of MF and BA magmatic rocks. These controls diminished the geochemical and isotopic variations between the magmatic front and backarc.

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Section: Discussionsupporting

confidence: 71%

Neotethyan Subduction Ignited the Iran Arc and Backarc Differently

Moghadam

et al. 2020

JGR Solid Earth

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“…granite, granodiorite, and tonalite) from the South Bohemian Batholith (Liew et al 1989 ; Fuchs and Thiele 1968 ) and the Austrian Hohe Tauern Batholith (Finger and Steyrer 1988 ). 9: a volcanic-arc granodiorite (I-type) from the Zagros orogen in Iran (Alaminia et al 2013 ). 10: fractionated biotite-amphibole granite from the Boggy Plain high-T, I-type suite (Wyborn et al 1987 ; Chappell et al 1998 ).…”

Section: Modeling – T and – mentioning

confidence: 99%

Application of Ti-in-zircon thermometry to granite studies: problems and possible solutions

Schiller

Finger

2019

Contrib Mineral Petrol

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157

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The application of the Ti-in-zircon thermometer to granitic rock requires consideration of and during zircon crystallization. Thermodynamic software programs such as rhyolite-MELTS or Perple_X permit the estimation of and values from whole-rock geochemical data as a function of pressure and temperature. Model calculations carried out on a set of 14 different granite types at 2 kbar, 5 kbar, and H 2 O = 3 wt% show during zircon crystallization close to 1 (0.75–1) and generally far below unity (0.1–0.6). This would suggest that Ti-in-zircon temperatures for granites must be significantly upward corrected relative to the original TiO 2 - and SiO 2 -saturated calibration of the thermometer. Both the rhyolite-MELTS and Perple_X calculations indicate that is typically around 0.5 in ilmenite-bearing granites. Thus, for ilmenite-series granites (that is, almost all S-type and many I-type granites), it could be a reasonable first order approximation to apply a constant temperature correction of + 70 °C to the Ti-in-zircon thermometer. Granites lacking the paragenesis zircon–ilmenite, that is, some A-type granites and a few special I-type granites may have even lower (0.1–0.5) and some of them may require a huge upward correction of Ti-in-zircon temperatures on the order of 100–200 °C. Using a set of Ti-in-zircon measurements from a Variscan granite of the Bohemian Massif, we introduce a novel T -dependent and correction of Ti-in-zircon calculated temperatures which is based on -, – T functions modelled with rhyolite-MELTS. This method takes into account that early and late zircons in granitic systems may crystallize at different and . Furthermore, we highlight the usefulness of comparing the corrected results of Ti-in-zircon thermometry with bulk-rock-Zr-based zircon solubility thermometry and ideal zircon crystallization temperature distributions for granites, and we present a graphical method that enables this comparison. In addition, this paper addresses the problem that Ti-in-zircon measurements are commonly collected with only moderate spatial analytical resolution, which leads to an averaging effect and to difficulties in recording accurate crystallization temperatures. Therefore, we propose that Ti-in-zircon thermometry for granites should generally rely on the more representative median- T ( T med ) value of a series of zircon analyses. Peak magma temperatures will be, in general, 35–50 °C above T med , as can be modelled using zircon crystallization temperature distributions.

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“…In addition to the ophiolitic assemblage, there are a large number of post-ophiolitic rocks in SR. These rocks appear as various plutonic, sub-volcanic and volcanic bodies, and many of them have adakitic properties [3,19,29,40].…”

Section: Geological Background and Sample Selectionmentioning

confidence: 99%

Geochemical and environmental investigation of sewage-irrigated soils and crops of Sabzevar, NE of Iran

2019

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The present study identifies the effects of sewage irrigation on the surface soils geochemistry and the concentration of heavy metals in plants of Sabzevar area, which were irrigated for a long time by wastewater. This study shows that the sewage irrigation has led to decreasing pH and increasing organic matter, and also it makes the accumulation of P 2 O 5 , high-field-strength elements (Ga, Ta, Th, U and Y) and heavy metals (Cd, Co, Cu, Pb, Sn and Zn) in contaminated soils. Likewise, the concentration of rare-earth elements (REE) in contaminated soils is more than background samples with moderate enrichment of light REE compared with high REE in REE pattern diagram (mean La N /Lu N = 5.77). The calculated transfer factor and enrichment factor indexes in plants grown on the polluted soils are significantly higher than the control samples which show the heavy metal enrichment in the contaminated samples. Although the cultivated crops on this area (maize, beet, alfalfa, barely) are used only for animal feed, the heavy metal analysis indicated that the concentration of Cr, Cu, Ni and Pb in these plants, especially alfalfa and maize, is more than the maximum permitted levels defined in different standards.

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The magmatic record in the Arghash region (northeast Iran) and tectonic implications

Cited by 34 publications

References 33 publications

Neotethyan Subduction Ignited the Iran Arc and Backarc Differently

Neotethyan Subduction Ignited the Iran Arc and Backarc Differently

Application of Ti-in-zircon thermometry to granite studies: problems and possible solutions

Geochemical and environmental investigation of sewage-irrigated soils and crops of Sabzevar, NE of Iran

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