The metallogenic epoch and ore-forming metal source of some large and superlarge deposits in laojunshan, Yunnan- Evidence from Rb-Sr isotopic studies

摘要

The Laojunshan metallogenic district located in southeastern Yunnan is an important tin polymetallic metallogenic district in China. The Dulong (tin-zinc polymetal, superlarge), Xinzhai (tin, large) and Nanyangtian (scheelite, large) are the main deposits in this district. These deposits outcrop in the Lower-Middle Cambrian metamorphic series, and most orebodies that associated with skarns colsely are stratoid, lenticular in occurrence and in accordance with the wall rocks. Distributed around the Laojunshan granite, the above-mentioned deposits were considered to be of magmatic-hydrothermal origin, But recent researches have launched challenge to this viewpoint. In this note, we will discuss the metallogenic epoch and oreforming metal source of these deposits in terms of Rb-Sr isotopic studies.