气候变化领域集成服务门户(CCPortal): Petrogenesis of the Cretaceous granitoids in Zhejiang, northeast South China Block and their implications for episodic retreat and roll-back of the Paleo-Pacific Plate

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DOI	10.1130/B35426.1
	Petrogenesis of the Cretaceous granitoids in Zhejiang, northeast South China Block and their implications for episodic retreat and roll-back of the Paleo-Pacific Plate
	Tao L.; Pan F.-B.; Liu R.; Jin C.; Jia B.-J.; He X.
发表日期	2020
ISSN	167606
起始页码	1514
结束页码	1536
卷号	132 期号:2021-07-08
英文摘要	Two Cretaceous granitoid belts (i.e., the northwest and southeast belts) have been identified in Zhejiang, northeast South China Block. In this study, seven granitoid plutons from both the two belts were collected for zircon U-Pb dating, whole-rock geochemistry, Sr-Nd isotope, and zircon Hf isotope analyses. Chronologically, the Longyou (132 Ma), Sucun (136 Ma), Shanghekou (131 Ma), and Huangshitan (ca. 126 Ma) plutons from the northwest belt display older magma crystallization age than those of the Xiaoxiong (100 Ma), Zhujiajian (108 Ma), and Qingbang island (108 Ma) plutons from the southeast belt. The Sucun quartz monzonite and the Longyou, Shanghekou, Zhujiajian, and Qingbang island granites therein are fractionated I-type granites (i.e., partial melting of meta-igneous rocks) with relatively moderate-low Zr saturation temperature (723-823 °C) and pronouncedly evolved Nd and Hf isotopic compositions (εNd(t) =-8.17 to-5.67 and εHf(t) =-15.07 to-5.67), indicating that they are derivatives of ancient crustal melt-dominated magmas. The Huangshitan granite shows A-type granitic (i.e., granites that are alkaline and anhydrous and from anorogenic setting) features with high Ga/Al (3.47-5.58), rare earth element (REE) content (271-402 ppm), and Zr saturation temperature (781-889 °C). It holds less enriched Nd and Hf isotopic compositions (εNd(t) =-4.13 to-3.60 and εHf(t) =-5.90 to-2.16) and is attributed to partial melting of mature crustal materials with minor basaltic magma incorporation. The Xiaoxiong (quartz) syenitic porphyry is characterized by moderate SiO2 content (60.68-69.92 wt%), high alkali (9.03-11.66 wt%) and REE contents with fractionated REE pattern [(La/Yb)N = 13.8-26.1]. Its relatively depleted Nd and Hf isotopic compositions (εNd(t) =-3.67 to-3.42 and εHf(t) =-5.76 to-2.25) imply that it could be a derivative of basaltic magma from K-rich metasomatized mantle. Available geochronological data indicate that there were two episodic magmatic pulses at ca. 140-120 Ma and ca. 110-85 Ma associated with the Paleo-Pacific Plate underthrusting beneath the northeast South China Block. Here we put forward an episodic slab retreat and roll-back model to account for generation of these magmatic rocks. Firstly, the subducting Paleo-Pacific slab roll-back initiated at ca. 140 Ma and reached climax at ca. 130-120 Ma, which led to formation of the Longyou, Sucun, and Shanghekou I-type granites and the Huangshitan A-type granite, respectively. Subsequently, a flat slab subduction stage occurred with eastward trench retreat, causing a period of magmatic quiescence from ca. 120 to 110 Ma. The following second slab roll-back started at ca. 110 Ma and reached climax at ca. 100 Ma, giving rise to the earlier Zhujiajian and Qingbang island I-type granites and the later Xiaoxiong (quartz) syenitic porphyry. © 2019 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/184750
作者单位	State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences, Wuhan, 430074, China; Faculty of Earth Science, China University of Geosciences, Wuhan, 430074, China; Zhejiang Institute of Geology and Mineral Resource, Hangzhou, 310007, China; Ocean College, Zhejiang University, Hangzhou, 310058, China
推荐引用方式 GB/T 7714	Tao L.,Pan F.-B.,Liu R.,et al. Petrogenesis of the Cretaceous granitoids in Zhejiang, northeast South China Block and their implications for episodic retreat and roll-back of the Paleo-Pacific Plate[J],2020,132(2021-07-08).
APA	Tao L.,Pan F.-B.,Liu R.,Jin C.,Jia B.-J.,&He X..(2020).Petrogenesis of the Cretaceous granitoids in Zhejiang, northeast South China Block and their implications for episodic retreat and roll-back of the Paleo-Pacific Plate.Bulletin of the Geological Society of America,132(2021-07-08).
MLA	Tao L.,et al."Petrogenesis of the Cretaceous granitoids in Zhejiang, northeast South China Block and their implications for episodic retreat and roll-back of the Paleo-Pacific Plate".Bulletin of the Geological Society of America 132.2021-07-08(2020).