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| LA-ICP-MS ZIRCON U-Pb DATING AND GEOCHEMISTRY OF THE VOLCANIC ROCKS FROM MANITU FORMATION IN ULANHOT REGION OF SOUTHERN DAXINGANLING |
| TAO Chuan-zhong1,2, LI Zhu-min2, WANG Da-qian2, SHEN Xin2, ZHANG Yu-jin1,2, LI Bin1,3 |
1. College of Earth Sciences, Jilin University, Changchun 130061, China;
2. Shenyang Institute of Geology and Mineral Resources, CGS, Shenyang 110034, China;
3. Jilin Institute of Geological Survey, Changchun 130061, China |
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Abstract The Manitu Formation volcanic rocks in Ulanhot region of southern Daxinganling belong to an acid, acid intermediate and intermediate rock assemblage of basaltic andesite, andesite, dacite and trachydacite. The LA-ICP-MS zircon U-Pb dating results show that the volcanic rocks are (142.2±1.0) Ma in age, formed at the beginning of Early Cretaceous, belonging to high-K calc-alkaline series with 53.93%-68.44% of SiO2 and 15.03%-17.82% of Al2O3, low total rare earth elements(ΣREE=103.48×10-6-147.09×10-6), distinct LREE and HREE fractionations with (La/Yb)N=6.68-9.12 and weak positive Eu anomalies(δEu=1.04-1.25). They are enriched in large ion lithophile elements(LILEs, such as Rb, Ba, Th, U and K) and light rare earth elements(LREE), whereas depleted in high field strength elements (HFSEs, such as Nb, P and Ti). The study shows that the volcanic rocks of Manitu Formation were formed in the closing stage of MongoliaOkhotsk Ocean under orogenic collisional tectonic setting, and might be the partial melting product of different residual mineral phases in thickened lower crust.
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Received: 13 February 2015
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2015, Vol. 24 
