气候变化领域集成服务门户(CCPortal): Thermotectonic evolution of the Paleozoic granites along the Shangdan suture zone (central China): Crustal growth and differentiation by magma underplating in an orogenic belt

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DOI	10.1130/B35466.1
	Thermotectonic evolution of the Paleozoic granites along the Shangdan suture zone (central China): Crustal growth and differentiation by magma underplating in an orogenic belt
	Qin J.-F.; Lai S.-C.; Long X.-P.; Zhang Z.-Z.; Ju Y.-J.; Zhu R.-Z.; Wang X.-Y.; Li Y.-F.; Wang J.-B.; Li T.
发表日期	2021
ISSN	167606
起始页码	523
结束页码	538
卷号	133
英文摘要	The nature of source rocks and the pressure- temperature-hydration (P-T-H2O) condition are the two main factors that control the geochemical properties of granites. Therefore, the evolution of P-T-H2O conditions can be used to deduce the tectonic setting of granites. In this paper, we report on three Paleozoic granite plutons along the Shangdan suture that revealed increasing melting temperature and decreasing pressure from 437 to 403 Ma, suggesting a crustal thinning process. The Tieyupu granodiorites (437 ± 4 Ma) display Na-rich adakite affinity, i.e., SiO2O = 69.1–70.1 wt%, Na2O/K2O = 1.9– 2.26, positive zircon εHf(t) values (+4.29 to +12.04), and high Sr/Y (137–160) and Y/Yb (9.89–10.25) ratios, implying a garnet-rich residue in their source. In combination with moderate zircon saturation temperatures (814–822 °C), we infer that the Tieyupu granodiorites were formed by melting of Neoproterozoic metabasites under highpressure (>1.5 GPa) and moderate-temperature (HP-MT) conditions. The Liangchahe granodiorites (415 ± 8 Ma) also display Narich adakite affinity, i.e., higher Na2O/K2O (2.16–3.11) and lower Sr/Y (77–88) ratios, and higher zircon saturation temperatures (854–874 °C), and they are interpreted to have been derived from melting of metabasites under moderate-pressure (>1.0 GPa) and high-temperature (MP-HT) conditions. Their variable zircon εHf(t) values (−14.97 to +9.80) and the existence of zircon xenocrysts suggest that the primitive adakitic melts were assimilated by evolved crustal components. The Yaogou monzogranites (403 ± 4 Ma) have the highest K2O/Na2O (0.81–1.00) ratios and total rare earth element (ΣREE; 105–191 ppm) contents, lowest Sr/Y (14–43) ratios, positive zircon εHf(t) values (+6.79 to +12.22), and highest zircon saturation temperatures (891–973 °C), showing they were formed by high-temperature melting of intermediate rocks under low-pressure conditions (<1.0 GPa). The evolution of P-T conditions revealed by these three granites suggests that crustal growth and differentiation were related to gradual extensional and melting of mafic protoliths in the orogenic belt. © 2020 Geological Society of America
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184695
作者单位	State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an, 710069, China; Shenyang Institute of Geology and Mineral Resources, Shenyang, 110034, China
推荐引用方式 GB/T 7714	Qin J.-F.,Lai S.-C.,Long X.-P.,et al. Thermotectonic evolution of the Paleozoic granites along the Shangdan suture zone (central China): Crustal growth and differentiation by magma underplating in an orogenic belt[J],2021,133.
APA	Qin J.-F..,Lai S.-C..,Long X.-P..,Zhang Z.-Z..,Ju Y.-J..,...&Li T..(2021).Thermotectonic evolution of the Paleozoic granites along the Shangdan suture zone (central China): Crustal growth and differentiation by magma underplating in an orogenic belt.Bulletin of the Geological Society of America,133.
MLA	Qin J.-F.,et al."Thermotectonic evolution of the Paleozoic granites along the Shangdan suture zone (central China): Crustal growth and differentiation by magma underplating in an orogenic belt".Bulletin of the Geological Society of America 133(2021).