| Eastern Jilin and Heilongjiang province, including the Taipinling,Xiaoxing’anling-Zhangguangcailing, Jiamusi-Xingkai, Wandashan, and Yanbianmetallogenic belts, have suitable geological conditions for prospecting potentialmineralizations. The region has abundant mineral resources, particularly gold, whichexists in a variety of types in proven and exploited gold deposits. However, with theincrease in the degree of geological prospecting and its associated difficulties,traditional and single prospecting methods have become inadequate in satisfying theneed for prospecting in complex geological conditions, particularly in complexlandscape and increased depth for prospecting. Therefore, exploration of concealedmineral deposits and comprehensive prospecting methods have become veryimportant.Considering the need for gold exploration in the study area, three typical golddeposits, Dongan epithermal-type, Jinchang hidden Breccia, and Madagou greenstonebelt metamorphic hydrothermal-type gold deposits, have been selected in this researchwork using comprehensive exploration methods. By collecting and carefully studyingprevious data, the following were achieved: analysis of the geological characteristicsof the deposits; integration of geophysical, geochemical, and other modernexploration techniques and tools; comprehensive and systematic study of the criteriafor prospecting the three typical gold deposits; establishment of a comprehensivemulti-scale mining and prospecting model for regional prospecting; and provision offast and effective prospecting methods and models for scientific exploration of golddeposits in eastern Jilin and Heilongjiang. The specific details of the work and resultsare as follows: (1) The three study areas are forested lands. Targeted technical methods ofgeophysical and geochemical exploration were selected to carry out experimentalwork on known orebodies. Using different techniques of prospecting and acomprehensive study on similar forest landscapes for exploring concealed goldorebodies, comprehensive exploration technology and methods were proposed fortechnical processes for the study areas.(2) High-precision ground magnetic survey data for the three typical gold depositsin the study area included analytic continuation, vertical derivative, derivative ofdifferent angles in the horizontal direction, and conjugate gradient magnetic anomalydimensional inversion. A clear, intuitive understanding was attained for the spacestructural framework and geological distribution, and both spatial location anddistribution of the orebody in the study area are given based on three-dimensionalinversion results, to provide an important basis for the exploration.(3) Controlled source audio magnetotelluric method (CSAMT) was be used forthe Dongan gold deposit. Continuous conductivity imaging (EH4) was used for theJinchang gold deposit. The results clearly showed an underground anti-breccia pipe.For further development of the gold mine, the hidden breccia-type gold deposit shouldbe explored to provide effective technical proof. For Ma up in the ditch gold, anexperimental work was carried out in the study area, and complex resistivity of2.5Dto four parameters were recorded with simultaneous complex resistivity inversion,verified by actual drilling2.5D inversion effect, to further clarify the actual geologicalsignificance of the four parameters.(4) In the three typical gold deposits, where dynamic research was conducted andgold was previously discovered in the forested lands, the gold content in organicmaterial comprised a share of the four highest percentages of extractable gold in theentire deposit. For the known gold orebodies in Dongan, the combination of iron andmanganese oxide phase exhibited obvious single peak shape or continuousmultimodal shape abnormalities; at the top of the known gold orebody in the goldmine, the combination of consecutive phases of the multimodal anomalies, iron andmanganese oxide phase showed no obvious abnormalities, but both sides of theorebody appeared to be abnormal; above the orebody of the known gold deposits in the ditch up hemp, the organic binder phase showed apparent unimodal shapeabnormalities, and the abnormal iron and manganese oxide phase occurred as acontinuous bimodal shape.(5) Gold at the top of the known orebody in Dongan were tested usingpyroelectric mercury method. The test results showed that in addition to the thermalrelease of mercury above the known orebodies having significant abnormalities inother tectonic belts, there are obvious exceptions. Mercury has a unique geochemicalproperty in that the heat release of mercury helps in determining the orebody structurewith significant indications.(6) Studying the three known orebodies in the study area using geophysical andgeochemical exploration methods and combining the results with that of previousstudies, a comprehensive prospecting model for the three areas have beensummarized. |
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