Study On Metallogenisis And Ore Structural-Controlling Of The Ailaoshan Gold Mineralization Belt

The Sanjiang region is one of the most productive and potential regions for metal resources in China.The Ailaoshan gold metallogenic belt is an important part of the Sanjiang region.Over the past several decades,the research for the Ailaoshan gold metallogenic belt has been focused on geological characteristics,mineralization and metallogenic mechanism.The achievement is prolific.Due to the complexity of regional geological background and the diversity of gold mineralization,there are still many problems in the study of gold deposits in this area,such as the types of gold deposits,ore-forming elements,ore-controlling factors,regional tectonic frameworks,ore-controlling law,metallogenic regularity and so on.In this context,this article carried out “Study on metallogenisis and ore structural-controlling of the Ailaoshan gold mineralization belt” through the typical gold deposits investigation,not only deepening the theoretical significance of mineralization,but also a realistic guide to the significance of ore prospecting.The main results of this paper are as follows:(1)Based on the geological characteristics and ore-controlling structure of Daping gold deposit,Chang'an gold deposit,Mojiang gold deposit,and Zhenyuan gold deposit of the Ailaoshan gold mineralization belt,the main ore-controlling structure property and deformation characteristics of the regional orogenic gold deposits were determined,which combined with the geological and geochemical analysis of the deposits.(2)Based on the analysis of ore-controlling structure,the multi-level and multi-order ore-controlling structure network of the Ailaoshan gold mineralization belt has been sorted out into three-level main ore-controlling structure framework.It is pointed out that the first-order ore-controlling structure is the ore-transmitting structure,the secondary-order ore-controlling structure is the rock-controlling and ore-transmitting structure,and the third-order ore-controlling structure is the ore-bearing structure.(3)The comprehensive research of geological bodies in different periods involved in the formation of the Ailaoshan orogenic gold deposits indicated that the Jinning period rocks were formed in the island arc tectonic environment under the background of the subduction of oceanic crust;The Late Permian rocks were formed in the active continental margin arc environment or the island arc tectonic environment under the circumstance of the subduction of oceanic crust;The Cenozoic rocks were formed in the active continental margin arc environment.The relationship between the evolution of magmatism and mineralization was also discussed.(4)We summarized the regional metallogenic regularity and comprehensively analyzed the regional metallogenic model of the Ailaoshan gold mineralization belt.During the early Himalayan period(58-44 Ma),affected by the collision between the Indian plate and the Eurasian plate,the Ailaoshan area suffered strong squeezing in the NWW-SEE direction,linking of the pre-existing structures,creating of NWW linear structural system,which had formed a huge ore-controlling structural network and a through fluid transport channel;During the middle Himalayan period(44-36 Ma),regional tectonic dynamic mechanism significantly changed,the Ailaoshan tectonic belt was dominated by the leftward strike-slip movement,forming the strike-slip fault system of each deposit,which further expanded the ore-controlling structure network.Ultimately,the accumulation and enrichment of ore-forming materials occurred in the favorable part of the structure site.(5)Based on the study of metallogenisis and ore structural-controlling,the Daping gold deposit is taken as an example to establish the ore structural-controlling model,which combined with the regional metallogenic regularity and continuous mineralization mechanism in depth scale.The prospecting direction of deep and periphery is alsopointed out.