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- W2985655641 abstract "Abstract Although continental crust is characterized by the widespread occurrence of granitoids, the causal relationship between continental crust growth and granitic magmatism still remains enigmatic. While fractional crystallization of basaltic magmas (with or without crustal contamination) and partial melting of mafic lower crust are two feasible mechanisms for the production of granitoids in continental arc regions, the problem has been encountered in discriminating between the two mechanisms by whole-rock geochemistry. This can be resolved by an integrated study of zircon U-Pb ages and Hf-O isotopes together with whole-rock major-trace elements and Sr-Nd-Pb isotopes, which is illustrated for Mesozoic granitoids from the Gangdese orogen in southern Tibet. The results provide geochemical evidence for prompt reworking of the juvenile mafic arc crust in the newly accreted continental margin. The target granitoids exhibit high contents of SiO2 (65.76–70.75 wt%) and Na2O + K2O (6.38–8.15 wt%) but low contents of MgO (0.19–0.98 wt%), Fe2O3 (0.88–3.13 wt%), CaO (2.00–3.82 wt%), Ni (<5.8 ppm), and Cr (≤10 ppm). They are enriched in large ion lithophile elements, Pb, and light rare earth elements but depleted in high field strength elements. The granitoids are relatively depleted in whole-rock Sr-Nd isotope compositions with low (87Sr/86Sr)i ratios of 0.7043–0.7048 and positive εNd(t) values of 0.5–2.6, and have relatively low 207Pb/204Pb and 208Pb/204Pb ratios at given 206Pb/204Pb ratios. Laser ablation–inductively coupled plasma–mass spectrometry and secondary ion mass spectrometry U-Pb dating on synmagmatic zircons yield ages of 77 ± 2–81 ± 1 Ma in the Late Cretaceous for their emplacement. Relict zircons have two groups of U-Pb ages in the late Mesozoic and the late Paleozoic, respectively. The whole-rock Sr-Nd isotopes in the granitoids are quite similar to those of Late Cretaceous mafic rocks in the Gangdese batholith. In addition, both synmagmatic zircons and relict zircons with Late Cretaceous U-Pb ages exhibit almost the same Hf-O isotope compositions to those of the slightly earlier mafic rocks. All these observations indicate that the granitoids were mainly derived from partial melting of the juvenile mafic arc crust. Therefore, reworking of the juvenile mafic arc crust is the mechanism for the origin of isotopically depleted granitoids in southern Tibet. It is this process that leads to differentiation of the juvenile mafic arc crust toward the felsic lithology in the continental arc. In this regard, the granitoids with depleted radiogenic isotope compositions do not necessarily contribute to the crustal growth at convergent plate boundaries." @default.
- W2985655641 created "2019-11-22" @default.
- W2985655641 creator A5011306686 @default.
- W2985655641 creator A5012324763 @default.
- W2985655641 creator A5038597407 @default.
- W2985655641 creator A5038855167 @default.
- W2985655641 date "2019-11-07" @default.
- W2985655641 modified "2023-10-18" @default.
- W2985655641 title "Geochemical evidence for the production of granitoids through reworking of the juvenile mafic arc crust in the Gangdese orogen, southern Tibet" @default.
- W2985655641 cites W1509769237 @default.
- W2985655641 cites W1559691030 @default.
- W2985655641 cites W1871734886 @default.
- W2985655641 cites W1964617878 @default.
- W2985655641 cites W1965561103 @default.
- W2985655641 cites W1967082613 @default.
- W2985655641 cites W1967719508 @default.
- W2985655641 cites W1969859799 @default.
- W2985655641 cites W1979705656 @default.
- W2985655641 cites W1981207838 @default.
- W2985655641 cites W1983339705 @default.
- W2985655641 cites W1985854661 @default.
- W2985655641 cites W1989556245 @default.
- W2985655641 cites W1991591808 @default.
- W2985655641 cites W1997142214 @default.
- W2985655641 cites W2003668476 @default.
- W2985655641 cites W2004433109 @default.
- W2985655641 cites W2004724861 @default.
- W2985655641 cites W2004780129 @default.
- W2985655641 cites W2005769501 @default.
- W2985655641 cites W2005807431 @default.
- W2985655641 cites W2005994637 @default.
- W2985655641 cites W2006196198 @default.
- W2985655641 cites W2006909936 @default.
- W2985655641 cites W2007105153 @default.
- W2985655641 cites W2010253617 @default.
- W2985655641 cites W2010457088 @default.
- W2985655641 cites W2013857416 @default.
- W2985655641 cites W2018682595 @default.
- W2985655641 cites W2018704618 @default.
- W2985655641 cites W2019748000 @default.
- W2985655641 cites W2022017333 @default.
- W2985655641 cites W2022276073 @default.
- W2985655641 cites W2022382004 @default.
- W2985655641 cites W2022859730 @default.
- W2985655641 cites W2023320566 @default.
- W2985655641 cites W2024585020 @default.
- W2985655641 cites W2025081092 @default.
- W2985655641 cites W2025765909 @default.
- W2985655641 cites W2028120826 @default.
- W2985655641 cites W2028298395 @default.
- W2985655641 cites W2030661236 @default.
- W2985655641 cites W2033267677 @default.
- W2985655641 cites W2037708864 @default.
- W2985655641 cites W2037923466 @default.
- W2985655641 cites W2039515073 @default.
- W2985655641 cites W2040126025 @default.
- W2985655641 cites W2040470138 @default.
- W2985655641 cites W2041837766 @default.
- W2985655641 cites W2042722986 @default.
- W2985655641 cites W2044911516 @default.
- W2985655641 cites W2044921168 @default.
- W2985655641 cites W2047567126 @default.
- W2985655641 cites W2047745886 @default.
- W2985655641 cites W2048857036 @default.
- W2985655641 cites W2051273227 @default.
- W2985655641 cites W2052574706 @default.
- W2985655641 cites W2053273118 @default.
- W2985655641 cites W2059010589 @default.
- W2985655641 cites W2060932144 @default.
- W2985655641 cites W2061262769 @default.
- W2985655641 cites W2062828467 @default.
- W2985655641 cites W2066270070 @default.
- W2985655641 cites W2069647204 @default.
- W2985655641 cites W2076395812 @default.
- W2985655641 cites W2078073473 @default.
- W2985655641 cites W2078105240 @default.
- W2985655641 cites W2082002326 @default.
- W2985655641 cites W2083108669 @default.
- W2985655641 cites W2083226499 @default.
- W2985655641 cites W2084886893 @default.
- W2985655641 cites W2086308255 @default.
- W2985655641 cites W2091441425 @default.
- W2985655641 cites W2093043576 @default.
- W2985655641 cites W2096276260 @default.
- W2985655641 cites W2097622004 @default.
- W2985655641 cites W2098262145 @default.
- W2985655641 cites W2098677480 @default.
- W2985655641 cites W2101782242 @default.
- W2985655641 cites W2102704186 @default.
- W2985655641 cites W2102828314 @default.
- W2985655641 cites W2104763301 @default.
- W2985655641 cites W2105265476 @default.
- W2985655641 cites W2109359181 @default.
- W2985655641 cites W2115108800 @default.
- W2985655641 cites W2115518283 @default.
- W2985655641 cites W2120265417 @default.
- W2985655641 cites W2126309541 @default.
- W2985655641 cites W2127172635 @default.