The Tin Polymetallic Prospecting Model And Ore Prediction Of Baiyinnuo Area In The Southern Segment Of Great Xing'an Range

The southern part of the Great Xing'an Range is located in the east segment of Central Asian Orogenic Belt,which experienced a superposition of multiple tectonic domain in the history of geological evolution period with the extensive development of Mesozoic granitic magma activity,especially a series of Sn-Cu-Mo-Pb-Zn-Ag polymetallic metallogenic explosion related to granites in the early Cretaceous intraplate extensional tectonic background,and became one of the most important tin polymetallic metallogenic belt in China.Based on the tin polymetallic metallogenic regularity and the typical deposit models,this contribution summarized the tin polymetallic metallogenic model,ore-controlling factors and prospecting indicators,and established the tin polymetallic prospecting model.Then,the metallogenic geological conditions of the Baiyinnuo area in the southern part of Great Xing'an Range were analyzed to explore the tin polymetallic mineralization potential in this area.Combined with the characteristics of geophysical and geochemical exploration and tin mineralization,regional ore prospecting was conducted and the prospecting target area was finally delineated.This contribution attained the following results and understanding.The metallogenic epochs of the tin polymetallic deposit ranged from 130 to 145 Ma and closely related to the Early Cretaceous granites.The genetic types of the deposits included granite type,skarn type,quartz vein type and sulfide vein type.Granite type,quartz vein type and sulfide vein type deposits are mainly controlled by magmatic action and fault structures,while the skarn deposits are also constrained by carbonate formations.Based on the study of tin-polymetallic mineralization characteristics and typical deposit models in the region,the ore-controlling factors,metallogenic model and ore-prospecting indicators of the magmatic hydrothermal tin polymetallic ore deposit in the southern part of the the Great Xing'an Range were preliminarily summarized,and a regional tin polymetallic prospecting model was established.Under the guidance of the regional tin polymetallic prospecting model,the metallogenic geological conditions of the Baiyinnuo area were analyzed,and it was considered that the area has the tin-polymetallic metallogenic potential.The magmatic activity in this area is mainly developed for large-scale Early Cretaceous granites,and there are also a few Indosinian granodiorites.Among them,the Early Cretaceous granites have the similar characteristics with regional tin polymetallic ore-forming granites.The fault structure in this area is very developed,mainly including two sets of faults,northeast regional faults and secondary north-northwest faults constitute a lattice-like fault system.Magmatic activities and fault structures provide excellent metallogenic geological conditions for the formation of tin polymetallic deposits.Combined with geophysical-geochemical exploration and remote sensing characteristics and the newly discovered tin mineralization characteristics,it is considered that the area has a great potential for tin-polymetallic prospecting.The study area is in a low-gravity and low-magnetic anomaly area,and a ring-shaped low magnetic anomaly can be seen locally.The combination of geochemical exploration anomalies is characterized by Sn,Cu,Pb,Zn,Ag.It is characterized by large scale and high anomaly intensity.Meanwhile,two large scale tin mineralization has been found in the area,and the mineralization patterns are represented by quartz vein type and greisen type.Thus two tin polymetallic prospecting areas were delineated,Haliheiba and Yaoerya target area,respectively,which indicated the direction for the next exploration work.