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Zircon U-Pb Ages and Hf Isotopes of Neoproterozoic Meta-Igneous Rocks in the Liansandao Area, Northern Sulu Orogen, Eastern China, and the Tectonic Implications.
- Source :
-
Journal of Earth Science . Dec2019, Vol. 30 Issue 6, p1230-1242. 13p. - Publication Year :
- 2019
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Abstract
- The Sulu Orogen preserves the Neoproterozoic tectonic-magmatic events, corresponding to the breaking up of the Rodinia supercontinent. The ages and petrogenesis of meta-igneous rocks in the Liansandao area in the northern Sulu Orogen are not well-constrained. This study reports zircon U-Pb ages and Hf isotopes of these rocks from the Liansandao area. Three meta-igneous rock samples give similar weighted mean 206Pb/238U ages of 744±11, 767±12, and 762±15 Ma, respectively, indicating the Neoproterozoic crystallization ages. These rocks formed coevally with the Wulian and Yangkou intrusions that located along the Yantai-Qingdao-Wulian fault zone. The Neoproterozoic ages indicate that the meta-igneous rocks from the Liansandao area have affinity to the Yangtze Block. The three samples have εHf(t)Hf(t) values of -7.2–-10.5, -6.0–-17.5, and -6.8–-12.0, respectively. These negative εHf(t) values indicate a primarily crustal source. However, the widely various εHf(t) values that are higher than the continental crust, suggesting magma mixing between mantle-derived materials and the continental crust or source heterogeneity. Combined with the Hf model ages and geochemical characteristics, the monzodiorite (sample LSD-2) is most likely to be mantle-derived magma then interacted with ancient continental crust, and the granitic protolith (samples LSD-1 and LSD-3) in the Liansandao area might derive from the re-melting of a Paleoproterozoic continental crust at ~750 Ma, resulting from the upwelling and underplating of mantle-derived magma formed in an extensional setting due to the break- up of the Rodinia supercontinent. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 1674487X
- Volume :
- 30
- Issue :
- 6
- Database :
- Academic Search Index
- Journal :
- Journal of Earth Science
- Publication Type :
- Academic Journal
- Accession number :
- 140356691
- Full Text :
- https://doi.org/10.1007/s12583-019-1252-7