Further quantitative calculations demonstrate that during the ductile shearing,gold was leached out of the wall rocks and then concentrated in the central part of the Shear zone together with gold carried by the external flulds.
The paper discusses geological features of Dexing nappe structure and its orecontrol significance and builds a polygenetic metallogenic model in which gold deposit and porphyry copper deposits are controlled by the ductile shearing nappe structure.
The regionnal large ductile sheer belt controls the distribution of theore zone or are field, the secondary brittle faults control the range of the ore deposit and the local interlagerfracture zone and faults fracture control the sites of the ore bodies.
By studying the macroscopic and microscopic features,the alteration and the geochemical characteristics of 210# sheer zone,it is shown that the enrichment and formation of gold mineralization is closely related with the stress evolution of 210# sheer zone. The gold mineralization mainly occurred in the formation stage of migmitization and alteration in the second period of the ductile sheer zone and was further enriched by the deformation of NE-SW anticlockwise strikeslip ductil sheering in the third period.
These rocks occur exclusively in high-temperature ductile shear zones, which can develop either during the primary exhumation of rock complexes or during the overprinting by high-temperature dynamometamorphism.
Ductile shear zones developed in Archean granulite gneisses simultaneously with their exhumation, and, hence, their P-T trajectories are segments of decompression and/or isobaric cooling paths.
Straight gneisses in Proterozoic polymetamorphic complexes commonly compose high-temperature ductile shear zones overprinted on Archean granulite complexes, and the P-T paths of these rocks are Z-shaped.
Such ductile shear zones commonly have a strike-slip morphology and can be easily seen in aerial photographs and discerned during structural geological surveying.
Fluid participation in ductile shear zone: Evidence from geological, geochemical and13O/16O relations from south part of Tanchen
The Duolanasayi gold deposit, 60 km NW of Habahe County in Xinjiang, is a medium-large scale gold deposit controlled by the coupled ore-forming processes involving brittle-ductile shearing, albitite veins, and post-stage magma solution.
The Duolanasayi gold deposit, 60 km NW of Habahe County, Xinjiang Uygur Autonomous Region, is a mid-large-scale gold deposit controlled by brittle-ductile shearing, and superimposed by albitite veins and late-stage magma hydrothermal solutions.
The second and main stage of gold mineralization was associated with renewed ductile shearing during D2.
To the south-west, in the Hornachos sector, large-scale recumbent folds associated with ductile shearing can be seen.
Later Devonian amphibolite-facies metamorphism caused ductile shearing of the pegmatites, leading to partial recrystallisation of pegmatitic material.
Jingshan superlarge gold deposit is a typical deposit closely related to the ductile shear zone, developing the economic enrichment during the transition form the ductile deformation to the brittle deformation.
The40Ar/39 Ar plateau ages, K-Ar date of K-feldspar and other geochronologic information suggest that the exhumation rate of the ductile shear zone is about 0.18-1.12 mm/a in the range of 107-70 Ma, which is mainly influenced by tectonic extension.
These kinds of shear types only produce a/ab strain facies, so the lineation in the ductile shear zone could not deflect 90° in the progressively deformation.
The present profile of the ductile shear zone with consistent SW-dipping mineral elongation lineation shows antiform and reversed S-shape from northeast to southwest respectively.
Exposure structures, microstructures and quartz C-axis fabric all indicate top-to-SW movement for the ductile shear zone.