High-Nb hawaiite–mugearite and high-Mg calc-alkaline lavas from northeastern Iran: Oligo-Miocene melts from modified mantle wedge

Ahmadi, Parham; Ghorbani, Mohammad Reza; Coltorti, Massimo; Kuritani, Takeshi; Cai, Yue; Fioretti, A. M.; Braschi, Eleonora; Giacomoni, Pier Paolo; Aghabazaz, Farzaneh; Babazadeh, Shahrouz; Conticelli, Sandro

doi:10.1080/00206814.2017.1416502

Cited by 8 publications

(10 citation statements)

References 96 publications

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“…Zircons from this sample yielded a weighted mean 206 Pb/ 238 U age of 24.2 ± 0.3 Ma. This agrees with the bulk rock 40 Ar‐ 39 Ar ages of 24.1 ± 0.4 and 22.9 ± 0.5 Ma for the intermediate to felsic volcanic rocks (Ahmadi et al, 2017).…”

Section: Geological and Geochronological Characteristics Of Ne Iran Bsupporting

confidence: 88%

“…MC volcanic rocks show variable compositions in the K 2 O + Na 2 O versus SiO 2 diagram (Figure 5b), ranging from trachy‐basaltic andesite to andesite‐dacite to trachyte (Ahmadi et al, 2017), but most are calc‐alkaline (Figure 5d). These rocks have both low and high Th/Yb ratio, but Nb/Yb ratio is high in all rocks (Figure 6b).…”

Section: Geochemical Characteristics Of Magmatic Episodes From Ne Iramentioning

confidence: 99%

“…In the QAP diagram, MC igneous rocks show dacitic‐andesitic to basaltic compositions (Figure 2e). Geochemically, these rocks are classified as high‐Mg basaltic andesites to dacites as well as high‐Nb hawaiites and mugearites (Ahmadi et al, 2017). Whole rock 40 Ar/ 39 Ar ages of 24.1 ± 0.4 and 22.9 ± 0.5 Ma are reported for the volcanic rocks (Ahmadi et al, 2017).…”

Section: Geological and Geochronological Characteristics Of Ne Iran Bmentioning

confidence: 99%

“…Cadomian rocks north of Bardaskan are from Moghadam, Li, Santos, et al et al (2017). Ar‐Ar data of Region c are from Ahmadi et al (2017). (c–e) Zircon U‐Pb age histograms of the magmatic pulses from Iran magmatic fronts (Regions 4 and 5 in Figure 1a) and backarcs (Regions 1 to 3).…”

Section: Introductionmentioning

confidence: 99%

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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: Geological and Geochronological Characteristics Of Ne Iran Bsupporting

confidence: 88%

Section: Geochemical Characteristics Of Magmatic Episodes From Ne Iramentioning

confidence: 99%

Section: Geological and Geochronological Characteristics Of Ne Iran Bmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Neotethyan Subduction Ignited the Iran Arc and Backarc Differently

Moghadam

et al. 2020

JGR Solid Earth

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“…The sediments were freeze-dried at − 50°C and powdered with an agate mortar and pestle, and~4 g of powder was pressed to obtain powder pellets (Ahmadi et al 2019). The trace elements were analyzed by x-ray fluorescence (XRF) with the pressed power pellets, using an ARL AdvantXP automated X-ray spectrometer (Ruzickova et al 2018).…”

Section: Sample Collection and Analysismentioning

confidence: 99%

Distribution and risk assessment of trace metals in riverine surface sediments in gold mining area

Song

Liu

Sheng

2019

Environ Monit Assess

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Recognizing the pollution characteristics and potential risks of trace metals in sediments are important to protect water ecosystem safety. In the present study, a systematic investigation was performed to assess the pollution and risk level of trace metals in river sediments located in the greatest gold production base in China. The geo-accumulation index was used to assess the contamination degree. The sediment quality guidelines and potential ecological risk index were employed to complete an ecological risk assessment. A noncarcinogenic health risk assessment was also carried out to evaluate potential adverse health risks. Correlations and principal component analyses were applied to check relationships among trace metals and ascertain potential pollution sources. The results suggested that the sediments in the river were most polluted by As, Cd, and Hg followed by Cu, Pb, and Zn. The assessment of potential human health risk revealed that there was no significant non-carcinogenic risk to the inhabitants. Gold mining and smelting activities and the long-term excessive application of fertilizers and agrochemicals were identified as the main anthropogenic releases. This study contributed an understanding that possible sources, contamination degree, and ecological risk level of trace metals in riverine surface sediments in a gold mining area.

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