Geochronology and geochemistry of the Cuihongshan Fe-polymetallic deposit, northeastern China; implications for ore genesis and tectonic setting

• Published in: Canadian journal of earth sciences Vol. 55; no. 5; pp. 475 - 489
• Main Authors: Zhang Yong, Zhang Yong, Sun Jinggui, Sun Jinggui, Xing Shuwen, Xing Shuwen, Zhang Zengjie, Zhang Zengjie
• Format: Journal Article
• Language: English
• Published: Ottawa National Research Council of Canada 01.05.2018; NRC Research Press; Canadian Science Publishing NRC Research Press
• Subjects: absolute age; Anomalies; Ar/Ar; Argon; Asia; chemical composition; China; Cuihongshan Deposit; Dating; Earth science; Economic geology; Far East; Feldspars; genesis; Geochemistry; Geochronology; Geochronometry; geodynamics; Geological research; Gold; Granite; Heilongjiang China; Iron; iron ores; Lead; Lead isotopes; lithostratigraphy; Magma; Mesozoic; metal ores; mica group; Mineralization; Molybdenite; Molybdenum; Natural history; nesosilicates; Niobium; Ores; Orogeny; orthosilicates; phlogopite; Plate tectonics; Radiometric dating; Re/Os; Rock; Rocks; Rubidium; sheet silicates; silicates; sulfides; Tantalum; tectonics; Titanium; Triassic; U/Pb; Upper Triassic; Uranium; Xiao Hinggan Ling; Zircon; zircon group; China
• ISSN: 0008-4077; 1480-3313
• DOI: 10.1139/cjes-2017-0178

The Lesser Xing'an Range is located in the eastern segment of the Central Asian Orogenic Belt. It hosts an important polymetallic metallogenic belt that contains more than 20 large- to small-scale porphyry Mo, epithermal Au, and skarn Fe-polymetallic deposits. The Cuihongshan Fe-polymetallic deposit is one of the largest polymetallic deposits in northeastern China. To better understand the formation of the Cuihongshan Fe-polymetallic deposit, we investigated the geological characteristics of the Cuihongshan deposit and applied geochemistry and geochronology to constrain the timing of the mineralization, and characteristics of the magmas. Zircon U-Pb dating of the alkali-feldspar granite and monzogranite yielded weighted mean 206Pb/238U ages of 495 ± 1.6 and 203 ± 1 Ma, respectively. Re-Os dating on molybdenite yielded an isochron age of 203.2 ± 1.4 Ma, and 40Ar/39Ar dating on phlogopite yielded an age of 203.4 ± 1.3 Ma. These data suggest that mineralization occurred during the Late Triassic, and is closely related with the monzogranite emplacement. These rocks belong to the high-K calc-alkaline and subalkaline series, are enriched in Rb, U, and Th, are depleted in Nb, Ta, and Ti, and show strong Eu anomalies, implying that they are A-type post-orogenic rocks. The Cuihongshan Fe-polymetallic formation is possibly related to an extensional environment resulting from the final closure of the Paleo-Asian Ocean.