On the role of contamination and hybridism in formation of the composite Raumid pluton granites (Pamir Mnts.): Results of Sm–Nd Isotope Study

Volkov, Vladimir; Шатагин, К. Н.; Kramchaninov, A. Yu.

doi:10.1134/s1028334x16090233

Cited by 4 publications

(2 citation statements)

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“…Previous studies have also identified Eocene igneous rocks in the Central and South Pamir terranes (Schwab et al, 2004;Stearns et al, 2015;Volkov et al, 2016), although there has been no effort to correlate this magmatism along strike or evaluate its tectonic significance. The results presented in this paper suggest that the Eocene igneous rocks are part of single magmatic complex that we refer to as the Vanj complex, because the rocks are most readily accessible along the Vanj river valley in the western Pamir (Fig.…”

Section: Cenozoic Magmatism In the Pamirmentioning

confidence: 99%

Mesozoic to Cenozoic magmatic history of the Pamir

Chapman

Scoggin

Kapp

et al. 2018

Earth and Planetary Science Letters

130

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New geochronologic, geochemical, and isotopic data for Mesozoic to Cenozoic igneous rocks and detrital minerals from the Pamir Mountains help to distinguish major regional magmatic episodes and constrain the tectonic evolution of the Pamir orogenic system. After final accretion of the Central and South Pamir terranes during the Late Triassic to Early Jurassic, the Pamir was largely amagmatic until the emplacement of the intermediate (SiO 2 > 60 wt. %), calcalkaline, and isotopically evolved (-13 to-5 zircon εHf (t)) South Pamir batholith between 120-100 Ma, which is the most volumetrically significant magmatic complex in the Pamir and includes a high flux magmatic event at ~105 Ma. The South Pamir batholith is interpreted as the northern (inboard) equivalent of the Cretaceous Karakoram batholith and the along-strike equivalent of an Early Cretaceous magmatic belt in the northern Lhasa terrane in Tibet. The northern Lhasa terrane is characterized by a similar high-flux event at ~110 Ma. Migration of continental arc magmatism into the South Pamir terrane during the mid-Cretaceous is interpreted to reflect northward directed, low-angle to flat-slab subduction of the Neo-Tethyan oceanic lithosphere. Late Cretaceous magmatism (80-70 Ma) in the Pamir is scarce, but concentrated in the Central and northern South Pamir terranes where it is comparatively more mafic (SiO 2 < 60 wt. %), alkaline, and isotopically juvenile (-2 to +2 zircon εHf (t)) than the South Pamir batholith. Late Cretaceous magmatism in the Pamir is interpreted here to be the result of extension *Manuscript Click here to view linked References directly south of the Tanymas-Jinsha suture zone, an important lithospheric and rheological boundary that focused mantle lithosphere deformation after India-Asia collision. Miocene magmatism (20-10 Ma) in the Pamir includes:1) isotopically evolved migmatite and leucogranite related to crustal anataxis and decompression melting within extensional gneiss domes, and; 2) localized intra-continental magmatism in the Dunkeldik/Taxkorgan complex. Bangong suture zone (Fig. 1) (Yin and Harrison, 2000). The Qiangtang terrane is laterally equivalent to (from north to south) the Central Pamir terrane, the South Pamir terrane, and the Karakoram terrane, whereas there is no direct equivalent of the Lhasa terrane in the Pamir (Fig. 1 and 2) (Robinson et al., 2012). The Central Pamir terrane was accreted to the Triassic Karakul-Mazar arc-accretionary complex along the Tanymas suture (Fig. 2) (Burtman and Molnar, 1993) and the Qiangtang terrane was accreted to the Triassic Songpan-Ganzi turbidite complex along the Jinsha suture in Tibet during Late Triassic-Early Jurassic time (Yin and Harrison, 2000). The Karakul-Mazar complex in the Pamir consists of relatively undeformed Late Triassic intermediate intrusive rocks that were emplaced into a Triassic accretionary complex (Schwab et al., 2004; Robinson et al., 2012). The Karakul-Mazar magmatic rocks are believed to have originated above a north-dipping subduction zone (Schwab et al...

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Section: Cenozoic Magmatism In the Pamirmentioning

confidence: 99%

Mesozoic to Cenozoic magmatic history of the Pamir

Chapman

Scoggin

Kapp

et al. 2018

Earth and Planetary Science Letters

130

View full text Add to dashboard Cite

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“…Recently, some geologists discovered that the formation ages of granodiorite from the northern margin of the South Pamir block are 170 Ma and 198 Ma (Schwab et al, 2004;Chapman et al, 2018). The monzonite was formed at an age of 75 Ma (Schwab et al, 2004), and the age of the granite formation was 40 Ma (Volkov et al, 2016). This indicates that there are also Early Middle Jurassic and Late Cretaceous magmatism events, in addition to Eocene magmatism, on the northern margin of the South Pamir block.…”

Section: Formation Age Of the Granitementioning

confidence: 99%

Petrogenesis and metallogenic significance of late Mesozoic granites in the Akjilga mining area, Tajikistan: constraints from geochronology and geochemistry

Li,

Hu,

Qin

et al. 2023

Front. Earth Sci.

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The Akjilga (Акджилга) mining area in Tajikistan sits in the central part of the Pamir syntaxis in the western part of the Indo–Eurasia collisional orogenic belt. Recently, the mineralization phenomena of skarn-type tin polymetallic ore bodies and dolomite-type rare-earth metals in the copper polymetallic mining area have been reported. However, the limited knowledge on the genesis of granite and its relationship with mineralization in this area hinders further research. Here, the Late Mesozoic granite rocks in the mining area were studied by petrology, geochemistry, and zircon U–Pb dating. The results showed that the rocks comprise majorly porphyric biotite syenogranite and minorly porphyric biotite monzogranite. The zircon U–Pb age of the porphyric biotite syenogranite was 108.3 ± 2.0 Ma, highlighting the Early Cretaceous period. The porphyric biotite syenogranite features high silicon and potassium contents and low iron, magnesium, calcium, sodium, titanium, and phosphorus contents. Furthermore, their aluminum saturation indexes were 1.11–1.21. Therefore, they were classified as high-potassium calc-alkaline strong peraluminous rocks. Trace-element analysis showed the enrichment of large ionic lithophile elements and light rare-earth elements (REEs); the deficiency of high-field-strength elements and heavy REEs; and the negative anomalies of Nb, P, and Ti. Compared with ordinary granites, the porphyric biotite syenogranite exhibits a higher differentiation index (91.20–93.96) and strong negative Eu anomaly (0.05–0.26), as well as a low Zr content and abnormally low Nb/Ta, Zr/Hf, Y/Ho, ∑LREE/∑HREE ratios. Therefore, the rocks are considered highly differentiated I-type granites with good Sn polymetallic and rare-metal prospecting potentials, and it resulted in the subduction-collision of the Rushan-Pshart ocean between the Middle Pamir block and the South Pamir block during the northward subduction process of the Late Mesozoic New Tethys ocean (Shyok ocean).

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