Ore-controlling Structures Of The Lamo Zn-Cu Deposit In The Nandan-binyang Metallogenic Belt,Guangxi

The Lamo Zn-Cu deposit is located in the southwest of the South China plate and the northern of the Nandan-Binyang metallogenic belt.This dissertation is based on the principle of constructing rock ore control theory,and based on field observations in the field.Combining with previous researches,the comprehensive study of the geological background of the Nandan-Binyang metallogenic belt,the form of the ore body,using ore structure analysis,microstructure,joint analysis,conjugate joint analysis,ore geochemistry,reveal the ore body geometry and tectonic kinematics,geometric patterns,elucidating the tectonic ore-controlling patterns and their interrelationships of the four types of ore bodies,ascertaining the ore-controlling laws of tectonics,and checking the origin of the Lamo deposit.The main achievements are:(1)According to its occurrence and characteristics,Lamo Zn-Cu orebody can be divided into four different types: Slowly inclined laminar orebody,high angle large vein orebody,high angle veinlike orebody,netted vein orebody.The ore-controlling patterns of the ore-controlling bodies are that the gently inclined bedded orebodies are controlled by the Indosinian NE-SW compression and the Yanshanian EW extension respectively,and the high-angle and large-vein orebodies are mainly controlled by NS faults.The high angle veined orebodies are controlled by NS faults,and the reticulated vein orebodies are mainly filled with conjugate joints formed along the early NE-SW direction.(2)The ore-controlling of the Lamo deposit is the NE-SW extrusion in the Indosinian period and the EW extension of the Yanshanian period,which controls the distribution of deposits on the metallogenic belt and causes left-side shearing due to the EW stretching of the Yanshanian period.Along with the continuity of the extension,the S-shaped area along the Danchi fault in the area plane is the favorable site for metallogenesis;in the section,the SW area has the potential to search for high-temperature deposits,and the deep NE area has the potential to search for low-temperature deposits.This provides indications for the further prospecting of the ore deposit.(3)The origin of the deposit was ascertained by collecting geochemical analysis of the former deposits and combining the study of ore-controlling.The ore-shaped ore bodies and vein-like ore deposits in the mine area are non-word-shaped,indicating that both were formed at the same time and were affected by the fracture of the NS Longxianggai during the mineralization period.The magmatic hydrothermal fluid upwells along the NS-trending fault,and the lateral migration metasomatism forms different types of skarn-type ore bodies.Based on data analysis of S isotopes,lead isotopes,oxygen isotopes,and fluid inclusions,ore-forming fluids are derived from magma.Therefore,it is concluded that the formation of the Lamo Zn-Cu deposit is formed by a magmatic hydrothermal deposit controlled by a structure instead of jet deposition.