ZIRCON U-Pb AGE AND Hf ISOTOPIC CHARACTERISTICS OF THE GNEISSIC GRANITES IN LAOZUOSHAN GOLDFIELD OF HEILONGJIANG PROVINCE: Geological Implication
KOU Lin-lin1, ZHANG Peng1, CHEN Jiang1, ZHAO Yan1, WANG Xiao-zheng2, BI Zhong-wei1
1. Shenyang Center of China Geological Survey, Shenyang 110034, China; 2. Core and Sample Center of Natural Resources, Sanhe 065201, Hebei Province, China
Abstract：The Laozuoshan gold deposit in Heilongjiang Province is a large hydrothermal superimposed skarn deposit in the north-central of Jiamusi block. Three groups of age, 697.1±8.0, 703.0±8.8, and 484.7±2.7 Ma respectively, are acquired through the LA-ICP-MS U-Pb dating and Hf isotope analysis of gneissic granites in the east ore belt of orefield, among which the former two are the age of captured zircons, suggesting that there might be Neoproterozoic crystalline basement in the south margin of Jiamusi block, and the latter represents the crystallization ages of gneissic granites. The zircon Hf isotope tests show that the εHf(t) ranges from -2.4 to +3.6, with TDM2 of 1620-1390 Ma, indicating that the protolith of gneissic granite may be the derived from the remelting of Mesoproterozoic continental crust material. Combined with the regional tectonic evolution, it is believed that the gneissic granite was possibly formed by the late Pan-African-early Caledonian collision-orogeny as the product of anatectic magma crystallization of Mashan Group.
Belousova E, Griffin W, O'Reilly S Y, et al. Igneous zircon:Trace element composition as an indicator of source rock type[J]. Contri butions to Mineralogy and Petrology, 2002,143(5):602-622.
Wu M, Li L, Sun J G, et al. Geology, geochemistry, and geochronology of the Laozuoshan gold deposit, Heilongjiang Province, Northeast China:Implications for multiple gold mineralization events and geodynamic setting[J]. Canadian Journal of Earth Sciences, 2018,55(6):604-619.
[14]
Yang J H, Wu F Y, Shao J A, et al. Constraints on the timing of uplift of the Yanshan Fold and Thrust Belt, North China[J]. Earth and Planetary Science Letters, 2006,246:336-352.
[15]
Amelin Y, Lee D C, Halliday A N, et al. Nature of the Earth's earliest crust from hafnium isotopes in single detrital zircons[J]. Nature, 1999,399(6733):252-255.
[16]
Amelin Y, Lee D C, Halliday A N, et al. Early-middle Archaean crustal evolution deduced from Lu-Hf and U-Pb isotopic studies of single zircon grains[J]. Geochimica et Cosmochimica Acta, 2000,64(24):4205-4225.
Wilde S A, Dorsett-Bain H L, Lennon R G. Geological setting and controls on the development of graphite, sillimanite and phosphate mineralization within the Jiamusi Massif:An exotic fragment of Gondwanaland located in north-eastern China?[J]. Gondwana Research,1999,2(1):21-46.
2020, Vol. 29 
辽公网安备 21010502000112号