Triassic-Jurassic Granitoids and Pegmatites from Western Kunlun-Pamir Syntax: Implications for the Paleo-Tethys Evolution at the Northern Margin of the Tibetan Plateau
| العنوان: | Triassic-Jurassic Granitoids and Pegmatites from Western Kunlun-Pamir Syntax: Implications for the Paleo-Tethys Evolution at the Northern Margin of the Tibetan Plateau |
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| المؤلفون: | Xiao-Shu Hao, Chuan-Lin Zhang, Xiao-Qiang Liu, Hai-Xiang Zhao, Haibo Zou, Xian-Tao Ye, Qian Wang |
| المصدر: | Lithosphere. 2020 |
| بيانات النشر: | GeoScienceWorld, 2020. |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | Paleontology, geography, Plateau, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Syntax (programming languages), Margin (machine learning), Geology, 010502 geochemistry & geophysics, 01 natural sciences, Pegmatite, 0105 earth and related environmental sciences |
| الوصف: | The Western Kunlun-Pamir-Karakorum (WKPK) at the northwestern Tibetan Plateau underwent long-term terrane accretion from the Paleozoic to the Cenozoic. Within this time span, four phases of magmatism occurred in WKPK during the Early Paleozoic, Triassic-Jurassic, Early Cretaceous, and Cenozoic. These voluminous magmatic rocks contain critical information on the evolution of the Tethys Oceans. In this contribution, we provide field observations, petrography, ages, whole-rock elemental and Sr-Nd isotopic compositions, and zircon in situ Lu-Hf isotopes of the Triassic-Jurassic granitoids and pegmatites from the Dahongliutan in Western Kunlun and Turuke area at the Pamir Plateau, in an attempt to constrain their petrogenesis and to decipher a more detailed Paleo-Tethys evolution process. The Dahongliutan pluton is composed of diorites (ca. 210 Ma) and monzogranite (ca. 200 Ma). The diorites have moderate SiO2 (56.77–62.22 wt. %), variable Mg# (46–49), and low Cr (34.4–50.6 ppm) and Ni contents (7.0–14.5 ppm). They show LREE-enriched patterns (LaN/YbN=4.3–17), with variable negative Eu anomalies (0.63–0.91) and variable ratios of Nb/La (0.27–0.97). Isotopically, the diorites display enriched whole-rock εNdt (-5.43 to -7.67) and negative to positive zircon εHft values (-6.6 to 0.4). They were most likely generated by melting of a subduction-modified mantle source with subsequent assimilation and fractional crystallization. The Turuke monzogranites (ca. 202–197 Ma) have S-type granite characteristics and are characterized by high SiO2 (70.36–76.12 wt. %) and A/CNK values (1.19–1.36), variable LREE-enriched patterns (LaN/YbN=8.87–14.40), negative Eu anomaly (0.07–0.56), relatively uniform whole-rock εNdt (-10.49 to -11.22), and variable negative zircon εHft values (-10.7 to -1.3). They were probably generated by muscovite-dehydration melting of dominantly metapelitic sources. The widespread pegmatites (ca. 195 Ma) at the Dahongliutan area record an extensional setting after the collision of Karakorum with the South Kunlun-Tianshuihai terrane. Combining our new data with the previous studies, we propose a divergent double-sided subduction of the Paleo-Tethys Ocean (243–208 Ma) and a gradual closure of the Paleo-Tethys Ocean from east (ca. 200 Ma) to west (ca. 180 Ma) to explain the Triassic-Jurassic tectono-magmatism in the WKPK. |
| تدمد: | 1947-4253 1941-8264 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::bcb0f39a562b672a96638edd52450f1b https://doi.org/10.2113/2020/7282037 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi...........bcb0f39a562b672a96638edd52450f1b |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 19474253 19418264 |
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