Formation Age and its Geological Significance of Quartz Diorite from Cryptoexplosive Breccia in Dalucao Rare Earth Mine, Sichuan Province

Abstract

To limit the diagenetic age of quartz diorite in the crypto-explosion breccia of the Dechang Dalucao in Sichuan Province, LA-ICP-MS zircon U-Pb chronology was carried out. The results show that the LA-ICP-MS U-Pb age of the Dalucao quartz diorite zircon is (751.7±4.6) Ma (n=39), indicating that the diagenetic age is Neoproterozoic, which is similar to the formation age of a large number of medium acid intrusions and volcanic rocks in the western and northern margins of the Yangtze Block. The Dalucao crypto-explosion breccia was formed in the shallow part of the crust, which provided a channel and favorable preservation conditions for the formation of rare earth deposits, suggesting that the deep part of the Dalucao has great potential for rare earth prospecting.

Keywords

• dechang
• dalucao
• quartz diorite
• zircon
• geological significance