Potential Assessment Of Superior Mineral Resource In Northwest Of Three-river Area, Yunnan Province

Directed by regional minerogenetic series theory,based on the analysis of minerogenetic geologic background,mineralization law and representative deposits,multi-source integrate information method and difference-seeking method were used here."Three-three" research approach for none-fuel mineral appraisal was established with core thought of Mineral Resource Assessment System(MRAS) on GIS platform.During research,geologic data of geological,geophysical,geochemical and remote sensing was collected and reinterpreted.The regional metallogeny background was analyzed base on research of strata and petrographic formation,geologic structure,magmatic rocks, mineral occurrences,gravity,magnetism,stream sediment,heavy sand and remote sensing. The relationship between geologic setting dividing,element combination,anomaly distribution and tectonic units was discussed.It was put forward that the perspective mineral deposit is porphyry copper deposit in Pulang-Mahuaping Area,which located between Geza river fault and Sanjiangkou-Jianchuan fault.The related magmatic rock are intermediate-acid intrusive rocks of Indo-Sinian Stage and Upper Stage of Yanshan,and alkali-rich porphyry of Himalayan Stage.After dissected representative copper deposits such as Pulang,Hongshan,and Beiya,the ore-control actions of geological,geophysical,geochemical and remote sensing were outlined qualitatively and quantitatively.The genetic model was established based on summarizing of metallogenic geological background,geological features of ore-body and deposit.Characters of minerogenetic series of Pulang-Mahuaping area were sum up,and regional metallogenic model was built up.With the guidance of the regional metallogenic model,on the basis of associative and integrated analysis of directed and undirected data of known deposits,i.e.regional geology, regional gravity,aeromagnetic,stream sediment survey,heavy sand wervey and remote sense data,different variates were extracted and constructed,including:occurrences;exposed intermediate-acid intrusive rocks;supposed intermediate-acid intrusive rocks deduced from geophysical,geochemical and remote sense data;faults,supposed linetype structures; negative residual abnormals area extended up to 5km on the maps of gravity and magnetism; the transition belt of between mantle syncline and mantle anticline;abnormals of Cu, CuWMo,CuWMoAuK₂O and PbZnAg;catchment basins of copper mineral abnormals delineated with 5 standard unit and 10 standard unit.Integrating information prospecting evidence weight was built by using MARS software based on geological statistic units.Grid cell of 2km×2km were used to calculate and predicted the locations.Prospecting areas were classified into A,B and C level.Finally,prospecting map was compiled and prospecting areas were appraised from geological aspect.By analysis of Geological and Mineral Resources Survey scaled 1:200000 and 1:50000, and deduced from geo-data of gravity-magnetic,geochemical and RS,some ore-controlling factors were extracted,which are intermediate-acid intrusive rocks,interpreted structures, geochemical anomalies and catchment basins of heavy mineral anomalies of copper.Followed the principle of "geologic body as appraisal unit,coverage as small as possible",45 possible areas were delineated,32 of which have outcrops of intermediate-acid intrusive rock,and 13 have hidden rock bodies.Resource quantity estimation with areal productivity method shows the metal quantities in working area are:copper 13,624 million tons,gold 9,026 ton,silver 2,557 million tons,lead 1,525 million tons,zinc 1,199 million tons,tungsten 10,736 million tons,molybdenum 466 million tons,beryllium 373 million tons.Minerogenetic series of copper polymetallic deposits has been identified and favorable areas with large metal potential were delineated.Further work for exploring large and super-large copper polymetallic deposits was suggested by the authors.