Structural sequence and its relationship with Cu-Ni sulfide ore deposit in the Jinchuan Area,Gansu,China
The ore-controlling structures in the Jinchuan Area have their own characteristics.A deeper nappe fault of the Luliang stage,occurring between the Bajiazuizi and Tamazigou groups,made the hanging strata of Baijiazuzi group to be intensively deformed,which associated with the later extensional tectonics,having created the condition for the penetrating of ore-bearing magma.The Jinchuan Area had been developed into a typical metamorphic core complex and accompanied with large-scale mafic-ultramafic magma intrusion during the Middle and Late Proterozoic.Qilian-orogeny was the major tectonic movement after the forming of the Jinchuan ore deposit.During the orogenic process,a series of thrust and strike-slip faults trending NWW made the Longshoushan metamorphic core complex to be gripped and bulged upward by the collision.It composed a palm tree structure that built up the major regional tectonic framework of this area.The Qilian-orogeny had also led to the rupturing,strike-slip and tilting of the original stratiform ore-bearing magmatic intrusions.Due to the uplift of the Tibetan Plateau,the new tectonic movement further pushed the ore-bearing magmatic intrusions NEE-wards onto the Cenozoic alluvium.