| Abstract: | After detailed geological prospecting and evaluation on Zhangyan copper deposit, the level of investigation on the geological characteristics of deposit has been raised. At the time to continue affirming the ore-generation of deposit has been controlled strictly by the contact belt between granodiorite body and Jinshan group,the layer of out-contact belt i. e. Jinshan group represented as a main ore-bearing rock-layer, has been divided in detail. The structure form of Jinshan group has been set up. The roles represented by component rock kinds of Jinshan group in ore-generation have been also collected in detail.
Jinshan group from the high to the low consists of upper hornfels segment, skarns segment and lower hornfels segment. In addition to skarns, they may be divided into calcium skarn and magnesium skarn. Calcium skarn is the main component part of skarns segment. Magnesium skarn, being with thin layer, stable and intermittently presents between layers of calcium skarn. In the west part of Baijiacun ore-segment, Jinshan group forms an almost vertical inseparable anticlinal structure. The calcium skarn is the main ore-embracing rock layer. The form and condition of occurrence of ore bodies completely has been coincide with calcium skarn. Magnesium skarn does not contain mineralization, it represents the role as an isolation layer in mineralization skarn. Both the upper and the lower hornfels segment represent the roles as two screen layers in ore-generation.
The genesis of Zhangyan copper deposit should belong to the contact metasomatic skarn type deposit and be related with intrusive activity of mid-acid magma, and with a more prominent stratigraphical controlling characteristics as well. |
