| The Shihu gold deposit is the onlylarge precious metal depositfound in northern Taihang Mountains.With more than 20 years ofproduction,its proven mineral reserves has not been much left.Therefore,strengthening the study ofmetallogenic regularities and making effective resources prediction to extend the service life of mineisa task of top priority.Based on the former publications,field observation and indoor assay were adopt to the further study of ore-controlling structures,quartz diorite porphyrite vein and wall-rock alteration of No.101 ore vein,the major industrial ore body in Shihu gold deposit.Combined with the primary halo,the metallogenetic regularity of Shihu gold deposit is summarized and the resource prospecting of deep part in No.101 vein is done.Shihu gold deposit is strictly controlled bystructures.The macroscopic and microscopic characteristicsof ore-controlling structures are analyzed,which indicates that the ore-controlling structures in Shihu gold deposit originated from the pre-Mesozoic joints,and traced and overlapped by Yanshanian NE tectonics;the relativeexpansionparts of the structures contribute to the thicker ore-body and higher grade,i.e.,rich orepillar.The rich ore pillars occurs as high-angle inclination,and integrally pitched southward in angle of 45 degree.The structural ore controlling regularityis of great help tothe deep ore-prospecting.Quartz diorite porphyrite is intimately related to gold mineralization.Petrographic and REE analysis are done to determine the relationship to the mineralization,the result indicates that there exists strong corrosion in porphyrite,and the thickness is positively related to the mineralized intensity,i.e.,quartz diorite porphyrite is indicative to the deep ore prospecting.Through field geological investigation,wall rock alteration is studied by microscopic identification and spatial comparison.The type,intensity and spatial zonation of wall rock alteration are determined,which shows that the width of wall rock alteration is highly related to the mineralization intensity.Ore-forming and associated elements in Shihu gold deposit are analyzed by multivariatestatistical method,and element composite is determined.The axial zonation is calculated by profile contour map and zonation indicator computation,and the elemental composite shows obvious "head and tail halo elements co-existing" which means the deep part mineralization of No.101 vein is prospective.On the basis of the whole research mentioned above,Shihu gold deposit is affected by lithology,structures and quartz diorite porphyrite.The Archean Tuanbokou and Nanying formation metamorphic rocks provide partial Au,the composite fracture of SN and NW provided a favorable place for mineralization,the quartz diorite porphyrite veins filled through the ore controlling structures and provided "mineralization agent".Combined with the resultsof primary halo,the area between 47 and 61 exploratory line and elevationally below 100m of No.101 vein is regarded to be excellent metallogenic prospect. |
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