First identification of postcollisional A-type magmatism in the Himalayan-Tibetan orogen

Hao, Lu‐Lu; Wang, Qiang; Wyman, Derek A.; Ma, Lin; Wang, Jun; Xia, Xiaoping; Ou, Qingyu

doi:10.1130/g45526.1

Cited by 29 publications

(24 citation statements)

References 18 publications

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“…Nd values based on the exponential law. Standard NIST SRM 987 was measured during the analysis of the Sr isotope, and the standards yielded an 87 Sr/ 86 Sr ratio of 0:710244 ± 22 (2SD, n = 32), within error to their published values (0:710241 ± 12). Standard JNdi-i was used during analysis of the Nd isotope, which yielded a 143 Nd/ 144 Nd ratio of 0:512118 ± 15 (2SD, n = 31) within error to their published values (0:512115 ± 07).…”

Section: Bulk Rock Major and Trace Elementmentioning

confidence: 57%

“…The adakitic rocks derived from the metasomatized mantle exhibit high K and Mg# (>50) [70]. In addition, potassic and ultrapotassic rocks are widely recognized as products of metasomatized lithospheric mantle melting [46], and the Miocene ultrapotassic rocks which were found in the Himalayan Orogen exhibit initial 87 Sr/ 86 Sr ratios of 0.719-0.721 and ε Nd values of -10.7--10.8 [73]. The Kuday adakitic rocks have low Mg, Ni, Cr contents, and Mg# (Figure 9), initial 87 Sr/ 86 Sr ratios of 0.707-0.711, and ε Nd values of -3.74--6.75 (Figure 8).…”

Section: Discussionmentioning

confidence: 99%

“…In addition, potassic and ultrapotassic rocks are widely recognized as products of metasomatized lithospheric mantle melting [46], and the Miocene ultrapotassic rocks which were found in the Himalayan Orogen exhibit initial 87 Sr/ 86 Sr ratios of 0.719-0.721 and ε Nd values of -10.7--10.8 [73]. The Kuday adakitic rocks have low Mg, Ni, Cr contents, and Mg# (Figure 9), initial 87 Sr/ 86 Sr ratios of 0.707-0.711, and ε Nd values of -3.74--6.75 (Figure 8). Consequently, it is unlikely that the Kuday adakitic rocks are related to the subducted oceanic plate or upper mantle metasomatized by the slabderived melts/fluids.…”

Section: Discussionmentioning

confidence: 99%

“…All of the samples display homogeneous Sr-Nd compositions. The Kuday granitoid porphyrite dikes have initial 87 Sr/ 86 Sr values ranging from 0.707 to 0.711 and ε Nd ðtÞ values ranging from -3.7 to -6.7. Two stages of Nd model age (TDM2) of these rocks range from 1005 to 1260 Ma.…”

Section: Sr-nd Isotopementioning

confidence: 99%

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Origin of the Miocene Adakitic Rocks and Implication for Tectonic Transition in the Himalayan Orogen: Constraints from Kuday Granitoid Porphyry in Southern Tibet

et al. 2022

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Postcollisional adakitic magmatism in the Himalayan Orogen provides a probe into the evolution of the collisional orogen. During the Miocene, the Himalayan Orogen underwent a tectonic transition, which was characterized by a series of tectonic events, including the activity of the North-South Trending Rift, exhumation of eclogite, rapid uplift of the orogen, and the extensive adakitic rocks. In this study, we reported the geochemistry and geochronological data of the Kuday dikes intruding into the Tethys Himalayan Sequence near the Sakya Dome of southern Tibet. The Kuday dikes are granitoid porphyries with zircon U-Pb ages of ca. 11 Ma. The Kuday granitoid porphyry dikes have high SiO2 (63.01–68.41 wt.%) and Al2O3 (17.31–19.87 wt.%) but low Mg (0.88–1.41 wt.%), Mg# (36–50), Ni (2.8–19.3 ppm), and Cr (2.9–26.4 ppm), indicating no input of mantle material. They have high Sr (934–1881 ppm), (La/Yb)N (18.84–113.13), and Sr/Y ratios (89.25–305.85) but low K2O/Na2O ratios (0.17–0.79), indicating that they are adakitic affinity. They display initial 87Sr/86Sr ratios of 0.707–0.711 and εNdt values of -3.7–-6.7. These geochemical signatures indicate that the Kuday granitoid porphyrite dikes were derived from the partial melting of the thickened lower crust of the Himalayan Orogen. Partial melting of the thickened lower crust requires additional heat, so the delamination model with lithospheric mantle thinning and asthenospheric upwelling is proposed to explain the formation of the Kuday adakitic rock. The delamination model can also provide a reasonable explanation for the tectonic events during the Miocene in the Himalayan Orogen.

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Section: Bulk Rock Major and Trace Elementmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Sr-nd Isotopementioning

confidence: 99%

See 2 more Smart Citations

Origin of the Miocene Adakitic Rocks and Implication for Tectonic Transition in the Himalayan Orogen: Constraints from Kuday Granitoid Porphyry in Southern Tibet

et al. 2022

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“…The Atype granites involving "alkaline" "anhydrous" and "anorogenic" characteristics are recognized in anorogenic and extensional tectonic settings (Eby, 1992). However, Atype magmas occurred throughout geologic time in different tectonic settings (Whalen et al, 1987), with recently published data (Ge et al, 2012;Hao et al, 2019;Xiao et al, 2019) providing robust examples that granitoids with A-type affinity also originate from a convergent plate boundary.…”

Section: Petrogenesismentioning

confidence: 99%

Geochemistry and Geochronology of the Cenozoic Zhalaga Granitoids of the Yulong Alkali‐rich Porphyry Belt in Eastern Tibet (Xizang), SW China: Petrogenesis and Tectonic Implications

Yuan

Xiao

et al. 2020

Acta Geologica Sinica (Eng)

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The Jinshajiang-Ailaoshan magmatic domain is a prolific polymetallic metallogenic belt in the Sanjiang region, SE Tibet Plateau that has attracted the attention of scientists worldwide (Xia et al., 2018; Yan et al., 2018). It hosts the Yulong porphyry copper belt (Fig. 1), an important porphyry copper belt related to collision in an orogenic environment (Chung et al., 2005; Deng et al., 2014a). This NW-SE-trending copper belt is about 400 km long and 15-30 km wide, comprising a giant ore deposit (Yulong), two large ore deposits (Duoxiasongduo and Malasongduo), and two medium-sized ore deposits (Zhalaga and Mangzong) (Knudsen et al., 2001; Deng et al., 2014a, b). The Cenozoic ore-bearing porphyry deposit, exposed along the Yulong porphyry copper belt, is characterized by alkali-rich rocks (Deng et al., 2014a) that are vital for understanding the tectono-magmatic processes in the Jinshajiang-Ailaoshan region. The Zalaga porphyry body outcropping in the northern Yulong porphyry copper belt (Fig. 1), based on K-Ar dating of K-feldspar and biotite (Liu and Zhao, 1981; Tang and Luo, 1995; Zhang et al., 1997) and zircon U-Pb dating (Liang et al., 2006; He et al., 2014), is assigned ages from ca. 33.9 to 41.0 Ma, highlighting multiple magmatic events and mineralization (Zhang et al., 1998). However, the petrogenesis of the Zalaga alkali-rich porphyry and tectono-magmatic processes in the Jinshanjiang-Ailaoshan region remain controversial. The four principal models proposed on the tectonic setting and

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Cenozoic ultrahigh-temperature metamorphism in pelitic granulites from the Mogok metamorphic belt, Myanmar

Chen

et al. 2021

Sci. China Earth Sci.

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First identification of postcollisional A-type magmatism in the Himalayan-Tibetan orogen

Cited by 29 publications

References 18 publications

Origin of the Miocene Adakitic Rocks and Implication for Tectonic Transition in the Himalayan Orogen: Constraints from Kuday Granitoid Porphyry in Southern Tibet

Origin of the Miocene Adakitic Rocks and Implication for Tectonic Transition in the Himalayan Orogen: Constraints from Kuday Granitoid Porphyry in Southern Tibet

Geochemistry and Geochronology of the Cenozoic Zhalaga Granitoids of the Yulong Alkali‐rich Porphyry Belt in Eastern Tibet (Xizang), SW China: Petrogenesis and Tectonic Implications

Cenozoic ultrahigh-temperature metamorphism in pelitic granulites from the Mogok metamorphic belt, Myanmar

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