Analysis Of Structural Characteristics Of The Youmachong Area In Guangxi And Its Control On The Formation Of Lead Zinc Ore

The Youmachong Pb-Zn deposits in Mengshan County of Guangxi is located on the Guidong polymetallic mineralization belt in the central Dayaoshan bulge and is controlled by the Dali-Pingxiang fault and secondary faults.The strata of the mining area are mainly the Cambrian Huangdongkou Formation and the Xiaoneihong Formation,which is a typical set of terrigenous clastic rocks.The magmatic activity in this area is relatively strong,mainly distributed along the Dali-Pingxiang fault.Which are mainly Caledonian granite porphyry and quartz porphyry,whose shape are small branches or dykes.The structure is mainly northeast-east fault.The deposits formed on the metallogenic belt of Dali--Pingxiang fault are mainly large and medium-sized precious metal deposits such as Gupao Gold Mine,Taohua Gold Mine,Chentang Gold Mine and Liuye Gold Mine.After mining by the state during the 1980 s and 1990 s,the quartz veins type gold deposits were first mined out,and then the gold deposits in the structural fracture zone were basically mined out.In the previous geological work,the main focus was on finding precious metals.However,little research was conducted on non-ferrous and rare metals in the same metallogenic belt.As the demand for metals such as lead-zinc deposits,molybdenum deposits gradually increased,the mining belts and surrounding areas have increased investment in exploration and have also achieved some results,such as Dali lead-zinc deposits,Dali molybdenum deposits,and Youmachong lead-zinc deposits(study area)in Mengshan County.With years of mining,the existing mining face has been gradually reduced.Youmachong lead-zinc deposits in Mengshan County has also entered the stage of “finding for blindness”.Therefore,this paper is based on the actual production situation of Youmachong lead-zinc deposits in Mengshan County and the contents of the prospecting project in the deep mining area and outside the mining area.Starting from the structural characteristics of the Youmachong area,the relationship between the deposits-controlling structure and the mineralization is analyzed.On the basis of collating and analyzing predecessors' research data,guided by disciplines or doctrines such as general geology,structural geology,sedimentology,sedimentary geochemistry,mineralogy,petrology,mineral deposits,and modern mineralization theory.The geological characteristics of the deposits in the Youmachong area were studied in detail,and then key researches and analyses were carried out on the deposits-controlling structures that were lacking in previous studies to explore: 1.Structural characteristics of the mining area and deposits-controlling structure formation and evolution process.2.The formation age of lead-zinc deposits.3.The relationship between deposits-controlling structures and mineralization.Through the study of the region,the following points were learned: 1.The metallogenic material was partially derived from the deposits-bearing rock.It first experienced an initial enrichment during the early Caledonian thermal event.The subsequent superimposition of thermal events in the late Indosinian-Yanshan period further enriched the metallogenic material.Finally,the deep magmatic fluids and some metallogenic materials along the faults caused by the Dali-Pingxiang fault in the late Yanshan period.The earlier enriched metallogenic material is further activated and eventually brought to a favorable slip site to mineralize.2.The deposits is controlled by the fault and fold.The fault structure is a good storage space and deposits-conducting structure where the deposits body is formed,and it is also a favorable prospecting site.3.The types of deposits are the hydrothermal quartz vein type lead-zinc deposits controlled by fractures,the sulfide lead-zinc deposits in the fracture zone,and altered-rock type lead-zinc deposits in the fracture zone.4.The area has a complex geological structure,rich metallogenic materials,excellent metallogenic conditions,and a great prospect for prospecting.