Strata Sequence And Diagenesis Process Of The Huo Geqi No.1 Deposit Of Langshan District In Inner Mongolia

Huogeqi copper-polymetallic deposit,which is one of typical deposits in lang mountain metallogenic belt locate in the western part of the northern margin of the North China Craton.its ore field structure has been controversial.The No.1 deposit of Huogeqi is a high-grade copper-polymetallic deposit possessing the most economic value in the three deposits in Huogeqi ore district.Stratigraphic sequence of the No.1 deposite was selected as the main concerned in this paper.The essential work focus on the surface profile measure,trenches documentation and underground rock observation.Meanwhile,the contact relationship between different strata was studied.Furthermore,in order to study the diagenetic processes and after detailed observations of sixty-five drills.its lithology was cataloged,also collectted geochemical data of all kinds of rock,analysis the rare earth elements characteristics detailed observation of the rock section and the transformation minerals under the microscope were performed.Firstly,regional stratum of the northern margin of the North China Craton were systematically compared,especially the Meso-Proterozoic strata.The regional tectonic setting and evolution of sedimentary rocks were also studied.Secondly,magmatic rocks surrounding the deposit were observed,especially on its transformation to ore body and metamorphic rock formations respectively.While the indicates significance of some quartzite veins structure have also done some research,based on drilling observation established the formation of strata characteristics.Orefield structure research mainly about the outcropping surrounding of the No.1 deposit,actrual works concern the transformation of amphibolite output status and form,the characteristics of faults,folds geometry,stretched minerals in rocks,the directions of the shear structure.Finally,we established the dextral shear which cut the deposit on the north of the NO.1 deposit,while the structure on the south side seems complex where are featured of overthrust fault and left-shear and high temperature stretching lineation.On diagenetic processes,micro-petrography characteristics of various types of rock underground were studied,established two evolutionary sequence carbonaceous and calcareous sequence,respectively:marble-diopside rocks-diopside tremolite-diopside tremolite quartzite-banded quartzite-siliceous quartzite,carbonaceous slate-silicified carbonaceous slate-carbonaceous quartzite-banded quartzite-silicified quartzite.Transition between the rocks are continuity,just the minerals,in the post-metamorphic processes,differentiation increases.Through 65 drills copper,lead and zinc grades curves change with depth and rare earth chemical characteristics of various types of rock further revealed various types of rock formation environment.