蒙古国巴彦洪格尔铜金矿集区地质特征及成因

巴彦洪格尔地区位于蒙古国中部 ,由古生代俯冲体系构成。该体系包括前寒纪微板块 (白得拉格和伯得高尔构造带 )、逆冲蛇绿岩带、加积型沉积岩 (巴彦洪格尔和得扎格构造带 )和弧前沉积岩 (可汗盖构造带 )。巴彦洪格尔地区岛弧岩浆作用主要以早古生代钛铁矿系列和晚古生代磁铁矿系列花岗岩类为特征。许多诸如斑岩型、矽卡岩型及脉岩型等各种类型的热液矿床与这些花岗岩类伴生。该区四大矿床的 K Ar同位素测年显示 :南方 Cu Au斑岩型矿床、呼布金洪迪矽卡岩型 Cu Au矿床、罕乌尔含金剪切带和塔磁高尔伟晶岩 W Au矿床的形成年龄值分别为 2 40± 5 Ma、2 5 2± 5 Ma、2 83± 6 Ma、32 9± 7Ma。由此可见 ,前三个地区的矿床与二叠纪—三叠纪初期磁铁矿系列花岗岩类具亲缘关系 ,而塔磁高尔W— Au伟晶岩则与早石炭世钛铁矿系列花岗岩类具亲缘关系。斑岩型和矽卡岩型 Cu— Au矿化作用发生在二叠纪末期—三叠纪初期 ,此时紧随着安第斯型岛弧岩浆作用 ,发生了白得拉格和塔巴嘎泰微板块的碰撞。

Geological Features and Origin of the Bayankhongor Region, Central Mongolia

The Bayankhongor region of central Mongolia comprises many Paleozoic and Precambrian microcontinents, obducted ophiolites and accretionary sedimentary rocks Igneous rocks are characterized by Late Paleozoic magnetiteseries granitoids In general, porphyry CuAu, skarn CuAu and shear zonehosted Au are genetically related to the Permian to Early Triassic magnetiteseries granitoids, whereas the WAu pegmatite to Early Carboniferousilmeniteseries granitoids Porphyry and skarn CuAu mineralization occurred at the latest Permian to the earliest Triassic, when the Andeantype arc magmatism was immediately followed by the collision among several microcontinents