A Study On Geochemical Characteristic Of Zhijiazhuang Iron Deposit In Laiyuan In Hebei Province

The Zhijiazhuang iron deposit in Hebei province is an typical skarn iron mine which is formed by Mesozoic tectonic-magmatic activity in the north section of Taihang Mountains.Since previous studies on the geochemical characteristics of Zhijiazhuang iron ore are not enough,based on the project of Study on the Rock and Ore Controlled Conditions and the Prospecting Direction of Tectonic-Magmatic in North Taihang(project number:1212011220865),which belonging to the subordinate project of Study on the Difficult Problems about Prospecting in Important Metallogenic Belt by China Geological Survey Bureau,through field geological survey and laboratory samples data analysis,this article makes an analysis of the rock and iron ore in open pit with the geochemical theory and tries to provide a basis for the future prospecting exploration work.The results obtained in this paper are as follows:(1)From the microscopic photographs under microscope,ICT slices and 3D maps,we find that the main texture of the iron ore in this zone is fine-grained structure,followed by replacement remnant ballistic texture;the iron ore are mainly of banded structure,the next is disseminated structure;the main metallic minerals are magnetite.(2)Magmatic ore body is located in the anticline of external contact zone of magmatic rocks and dolomite alteration zone,where the bedding of altered dolomite is nearly upright.The more violent of trends change in alteration zone,the more abundant deposit.(3)The magmatic rocks in this area are granite and quartz monzonite.Compared with the average value of Chinese granite,granite has a high silicon,high-sodium,high potassium,low titanium and low iron and low aluminum characteristics.From diopside skarn petrochemicals to magnetite skarn and then to the ore,the content of Si02 and CaO are gradually decreased,this means that the more seriousness of alteration,more silicon and calcium are brought out.Iron content has shown a rising trend and has reached more than 80%in the iron ore.(3)By the results of trace elements,we can draw that the depositional environment of dolomites of the Gaoyuzhuang Formation in the area is marine sedimentary with oxygen.From diopside skarn petrochemicals to magnetite skarn and then to the ore,the content of Rb,Ba and Nb are first increased and then decreased,while the content of Sr and Nd are continuing to decrease.(5)From diopside skarn petrochemicals to magnetite skarn and then to the ore,the content of Nd、Sm and Pr are gradually decreased,this means that the better of mineralization,the lower of the content of these elements.The iron content of skarn ore is higher and the total REE is lower,while the content of iron in skarn magnetite is lower and total REE is higher,which reveals that the content of total rare earth and iron may have a negative correlation relationship.The average ratio of ore Iron’s Y/Ho value is 28.57,indicating that mineralization is related to magmatic hydrothermal.The value of 8Eu and δCe also implies the formation of Zhijiazhuang iron deposit is in the low temperature and oxidizing environments.