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The petrogenesis and implications of deformed late Caledonian–early Hercynian granites in the Wuyi area, South China
Author(s) -
Zhao Xilin,
Jiang Yang,
Xing Guangfu,
Yu Minggang,
Liu Kai,
Chen Zhihong,
Yu Shengyao
Publication year - 2017
Publication title -
island arc
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.554
H-Index - 58
eISSN - 1440-1738
pISSN - 1038-4871
DOI - 10.1111/iar.12203
Subject(s) - zircon , geology , geochemistry , metamorphism , precambrian , pluton , partial melting , petrogenesis , basement , geochronology , continental crust , crust , mantle (geology) , paleontology , tectonics , archaeology , history
Precambrian basement rocks have been affected by Caledonian thermal metamorphism. Caledonian‐aged zircon grains from Precambrian basement rocks may have resulted from thermal metamorphism. However, Hercynian ages are rarely recorded. Zircon U–Pb Sensitive High Resolution Ion Microprobe (SHRIMP) dating reveals that zircon ages from the Huyan, Lingdou, and Pengkou granitic plutons can be divided into two groups: one group with ages of 398.9 ±5.3 Ma, 399 ±5 Ma, and 410.2 ±5.4 Ma; and a second group with ages of 354 ±11 Ma, 364.6 ±6.7 Ma, and 368 ±14 Ma. The group of zircon U–Pb ages dated at 410–400 Ma represent Caledonian magmatism, whereas the 368–354 Ma ages represent the age of deformation, which produced gneissosity. The three plutons share geochemical characteristics with S‐type granites and belong to the high‐K calc‐alkaline series of peraluminous rocks. They have ( 87 Sr/ 86 Sr) i ratios of 0.710 45–0.724 68 and εNd(t) values of −7.33 to −10.74, with two‐stage Nd model ages ( T DM 2 ) ranging from 1.84 Ga to 2.10 Ga. Magmatic zircon εHf(t) values range from −3.79 to −8.44, and have T DMC ages of 1.65–1.93 Ga. The data suggest that these granites formed by partial melting of Paleoproterozoic to Mesoproterozoic continental crust. A collision occurred between the Wuyi and Minyue microcontinents within the Cathaysia Block and formed S‐type granite in the southwest Fujian province. The ca 360 Ma zircon U–Pb ages can represent a newly recognized period of deformation which coincided with the formation of the unified Cathaysia Block.