Zircon U-Pb Age and Hf Isotope Characterization of Sheshan Granodiorite in Southern Edge of Dayaoshan,Guidong:Constraints on Caledonian Diagenesis and Mineralization
Li Wei
Bi Shijian
Yang Zhen
Liang Pei
Tang Kefei
Abstract：In this paper,we present laser ablation (MC)-ICP-MS U-Pb dating and Hf isotopic compositions of zircons from two representative granitoid samples collected from Shedong W-Mo deposit in the southern edge of the Dayaoshan.Highly precise U-Pb results indicate that zircons from Sheshan biotite granodiorite (SD256)and granodiorite-(porphyry)(SD1 90)which em-placed in the Pingtoubei quartz sandstone yields weighted mean 206 Pb/238 U age of 438.7±3.0 Ma (MSWD=0.22)and 438.1± 2.6 Ma (MSWD = 0.28 ),respectively.And the zircons crystallized in the Kwangsian granites yield 1 7 6 Hf/1 7 7 Hf ratios of 0.282 406 to 0.282 5 18,εHf (438 Ma)values ranging from -3.7 to 0 and Hf model ages (T DM2 )of 1 226 to 1 41 7 Ma.Our U-Pb and Hf isotopic data can be interpreted as the crystallization time of granites,and indicate that it was formed in the~438 Ma (Caledonian)and may have been formed by reworking of Mesoproterozoic juvenile crust (1.2-1.4 Ga)closely related to partial melting.Together with other published geochronological data,it is proposed that the late Early Paleozoic granites predominantly have a similar formation age and exhibit a planar-shaped distribution, rather than a north-east-striking-distribution pattern in the hinterland of the South China.Moreover,the Caledonian tectonic-magmatic-metallogenic movement may be the one of key reasons for the large-scale magmatism and metal mineralization in the following tectonic episodes,such as Indosinian and Yanshanian in the South China.
Keywords：Shedong W-Mo depositgeochemistryCaledoniandiagenesis and mineralizationDayaoshan
Publication Date：2015-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：17( 17-33 )