Browsing by Author "Chen, Z."
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Item Early Mesozoic tectono-magmatic activity and mineralization in northeast China: Evidence from Re-Os to U-Pb studies of the Taipingchuan porphyry Cu-Mo deposit in the Derbugan metallogenic belt(International Geology Review, 2014-10) Zhang, L.; Gao, B.; Li, W.; Chen, Z.; Sakyi, P.A.; Jin, X.The Taipingchuan Cu-Mo deposit is a recently discovered large porphyry deposit located in the north of the Derbugan metallogenic belt of northeastern China. The geochronological data of the deposit yielded a Late Triassic zircon U-Pb age of 202 ± 6 Ma from a granodiorite porphyry that hosts the Cu-Mo mineralization. Measured Re-Os isotopes of seven disseminated molybdenite samples yielded an isochron age of 200 ± 5 Ma with mean square of weighted deviates of 2.7, while those of seven veinlet molybdenite samples also produced an isochron age of 200.1 ± 2.5 Ma and mean square of weighted deviates of 3.3. These isochron ages show that a Cu-Mo mineralization event occurred at ca. 200 Ma. Based on regional tectonic evolution, we propose that the Late Triassic Cu-Mo mineralization of the host porphyry in the Derbugan metallogenic belt was mainly associated with the subduction of the Mongol-Okhotsk Ocean slab under the Ergun block, contrary to previous suggestion that it was related to the subduction of the Mesozoic Palaeo-Pacific plate. © 2014 Taylor & Francis.Item Formation age and genesis of the Gongchangling Neoarchean banded iron deposit in eastern Liaoning Province: Constraints from geochemistry and SHRIMP zircon U-Pb dating(Precambrian Research, 2014-11) Han, C.; Xiao, W.; Su, B.-X.; Sakyi, P.A.; Chen, Z.; Zhang, X.; Ao, S.; Zhang, J.; Wan, B.; Zhang, Z.; Wang, Z.; Ding, J.The Gongchang iron deposit, a typical Algoma-type banded iron formation (BIF) deposit located in the Eastern Block of the North China Craton (NCC), is hosted in Neoarchean metamorphic rocks, including amphibolite, biotite leptynite, garnet biotite schist, plagioclase-hornblende schist, garnet chlorite schist, muscovite quartz schist and actinolite magnetite quartzite. Geochemical data suggest that protoliths of the amphibolites and biotite leptynite should be basalt and dacite, respectively. SHRIMP U-Pb dating of zircons from the plagioclase-hornblende schist shows that the Gongchangling iron deposit was formed at 2554±12Ma. Major elements and REE data of the ores indicate that the Gongchangling BIF precipitated from seawater, and the ultimate iron and silica origins may have been related to nearby volcanic activity. The δ18O values of quartz from the BIFs range between 9.1 and 12.9‰, suggesting that exotic high δ18O fluids were involved during metamorphism. The pyrite have δ34S values of range between -3.5‰ and 14.7‰, suggesting that mineralization were originally from metamorphism. Comparison of the mineralization age of the Gongchangling BIF with those of other local BIFs in North China and other cratons throughout the world indicates that the Gongchangling BIF formed coevally with the global BIF mineralization at ~2.5Ga. Taken together, these data suggest that the Gongchangling iron deposit was formed in a volcanic submarine environment in which hydrothermal fluids associated with volcanic activity supplied both iron and silica for the banded iron formations. © 2014 Elsevier B.V..