Geochronology and Its Geological Implications of LA-ICP-MS Zircon U-Pb Dating of Granodiorite Porphyries in Dabaoshan Polymetallic Ore Deposit,North Guangdong Province
WANG Lei
HU Ming-an
YANG Zhen
CHEN Kai-xu
XIA Jin-long
Abstract：The dating of LA-ICP-MS zircon U-Pb was carried out for granodiorite porphyries at Dabaoshan polymetallic ore deposit in North Guangdong Province. In cathodoluminescence (CL) image, most zircons in two granodiorite porphyry samples exhibit oscillatory zoning, which is typical for magmatic zircon. The dating of LA-ICP-MS zircon U-Pb of two samples shows the results that 12 points of oscillatory zoned domains of Dabaoshan granodiorite porphyry sample yields a group of weighted mean ~(206) pb/~(238)U ages at (175.8±1.5)Ma (MSWD=0.037) and 16 points of oscillatory zoned domains of Chuandu granodiorite porphyry yields a group of weighted mean ~(206)Pb/~(238)U ages at (175.0±1.7) Ma (MSWD=0. 41). So the epoch of granodiorite porphyry emplacement is nearly 175 Ma, belonging to the first stage of the early Yanshanian (180--170 Ma). According to the precise ages we have obtained, Dabaoshan and Chuandu granodiorite porphyries are a whole magamtic rock divided by the post-mineralization fault, and the faulted space is the most important direction for further exploration of Mo-W. The study, together with others, suggests that its geodynamic setting was the same as that of the near magamatic rocks, which formed in the same episode lithosphere extension event in Nanling region. In addition, we conclude that in the first stage of the early Yanshanian, some granodiorite porphyries favorable to forming Mo-W deposits have been undiscovered in Nanling region.
Keywords：granodiorite porphyryzirconLA-ICP-MS U-Pb geochronologyDabaoshan ore deposit.
Publication Date：2010-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 175-185 )