大厂长坡锡-多金属矿床热释汞特征及分布规律

Characteristics and Distribution of Heat-released Mercury in Tin Polymetallic Deposit in Changpo of Dachang

关键词:  锡多金属矿床  热释汞  形成机理

Key words:  tin-polymetallic deposit  heat-released mercury  formation mechanism

摘要:

选择长坡锡矿区地表出露岩石剖面一条、近矿围岩井下已知剖面6条,采集岩石及矿体(矿石)样品共102个,加工为200目颗粒,用RG-1D型测汞仪,在700℃下测试分析。结果表明:大厂长坡锡-多金属矿床的热释汞,在空间上随矿体赋存明显呈由下到上的"三层楼"式分布,即下部似层状矿体含汞量 < 中部细脉型矿体汞量 < 上部裂隙脉型矿体汞量,汞随矿体沿构造滑脱面及裂隙带上升运移;在平面上似层网脉状矿体中部含汞量高,边部低,细脉状矿体边部高中间低,裂隙脉矿群底部低,顶部高,清晰地体现了汞运移扩散的路径。根据汞的运移和赋存形式推判汞异常形成过程为汞伴随深大断裂和多次的岩浆入侵上升,并在成矿过程中赋存于富含硫化物的矿床中,良好的容矿构造和矿石围岩岩性保障了汞的运移和赋存。

Abstract:

120 samples of rock and ore body were collected from a profile of the surfaced rock and six profiles of wall rock of near ore in Tin-polymetallic deposit of Changpo,Dachang.All samples were powdered at 200 eyes,and analyzed by RG-1D at 700℃.The heat-released mercury (HR Hg) in Tin-polymetallic deposit of Changpo,Dachang distributes in the pattern of three-layer in space.HRM increases in the order of layer-like mine (bottom) to thin-vein mine(middle) to fissured-vein mine.HR-Hg moves along with the rising activity of structural slippage plane and fissure-vein.In plane,HR-Hg in the middle of mine is higher than the edge in layer-like net mine,and reverses in thin-vein mine,and HR-Hg in the bottom of mine is higher than the top in fissure vein mine.The pattern and formatting deposit and movement of Hg reveals that Hg goes with deep large-fault activities and repetitious inbreak up of magma,and deposited in the rich sulfur deposits.The nice deposit structure and wall rock are favor to the movement and deposit of Hg.