关键词: Rb-Sr同位素, 成矿时代, 物质来源, 毛坪铅锌矿床, 滇东北

Abstract:

The Maoping Pb-Zn deposit is a typical ore deposit in the northeastern Yunnan province. However, there is no precise
geochronological data to date. This research performed Rb-Sr isotopic dating on four sphalerite separated from the Maoping deposit,
which yielded isochron age of 321.7 ± 5.8 Ma (MSWD=1.5), indicating that the mineralization age of the Maoping deposit was
Carboniferous. Moreover, the 87Sr/86Sr ratio of sphalerites is determined to be 0.712166 ± 0.000017. This result is lower than that of
continental crust (0.719) and higher than mantle (0.707), implying that the ore-forming metals were derived from continental crust with
a minor amount of mantle-derived materials. Combining with the previous studies, we propose that the Maoping deposit is an epigenetic
deposit similar to the typical MVT Pb-Zn deposits and its mineralization has no link with Permian Emeishan flood basalts. Moreover,
we also suggest that multi-stage Pb-Zn mineralization most likely occurred in the northeastern Yunnan province.

Key words: Rb-Srisotopes；mineralizationage；sourceofore-formingmaterials；MaopingPb-Znoredeposit；
northeasternYunnanprovince