DUCTILE SHEAR ZONE AND GOLD DEPOSITS IN WUCHUAN- GUYANG-DASHETAI INNER MONGOLIA
Sun Deyu Liang Yihong Zhang Yeming(Department of Geoloqy)
The mylonite in ductile shear zone in Wuchuan-Guyang-Dashetai area is rich in microfabrics.The mineral composition of the mylonite, as well as the test result of p-t condition of the mineral formation(t = 300-400C, p = 0.25-0.5GPa)indica-tes that the ductile shear zone was developed under the condition of defor- rmation and metamorphism of green shist facies. The value of shear strain (r) was measured as 5.77 3.4.It indicates that the deformation mechanism is simple shear and flattening.In the south of the ductile shear zone(Daqing Mt.and Wula Mt.), there i a strongly lineared structure of Early Froterczoic.In the north, there are oval structures and linear structures, the oval structures are dominated by Archaean metamorphic complex, the linear structures are dominated by green stones. The shear zone formed in Early Proterozoic.It shows the characteristic of ductile shear thrusting towards south.Along the shear zone gold deposits was distributed in band.The formation of the deposits is closely related to-the shear zone, especially those parts of which cut by brittle faults, as well as intruded by magmas. In those parts,gold further enriched. This suggests that the gold deposits had undergone multiple mineralization.