Deeo-Space Metallogenic Predication Study And Its Application In Jiaojia Gold Belt Of Shandong

Jiaojia gold belt in Shandong is one of the most famous gold mineralization belts in China. From 60s of 20th century up to now, the new type of gold deposit, namely Jiaojia type was discovered, which made gold mineralization theory abundant, and gold deposits exploration made breakthrough achievement in the belts. As mining depth becoming deep and deep in the belt, the new requirement of deep-exploration was put forwards to geological work. The aim of deep-depth gold deposits (bodies) prediction is not only to predict deep gold resource, to determine exploration targets and to direct deep gold deposits (bodies) exploration; but also to form a set of applied prediction method in order to promote deep minerals exploration entering a new stage in China.1 .Prospecting Models ConstructionProspecting models were constructed on the basis of study of mineralization-controll condition, prospecting information and mineralization regulation, and by systematically analysis of deposits (bodies) control-factors and prospecting signs. During the construction entirety, gradation, systematism and practicality of all geological information should be considered.1.1 Geological prospecting ModelBy study of mienralization-control condition and mineralization regulation of gold deposits in Jiaojia gold mineralization belt, the prospecting model was determined as following:1.1.1 Distribution areas of Jiaodong group, Linglong granites and Guojialing granites;1.1.2 NE-direction or NNE-direction faults development areas in the interior of stratigraphic units and intrusives, especially in the composite between faults and stratigraphic units or intrusives margins.1.1.3 Faults variation parts, such as fault direction changes, from narrow to wide, one fault changing to several or several composite, dip-angle change and so on.1.1.4 Gold liberalization had closely relationship with pyrite-Seri cite-quartz (PSQ), solidification, and potassium-sodium, therefore major ore bodies usually occurred in PSQ-cataclasite (mylonite) and PSQ-granitic cataclasite near main plane of faults; subordinate orebodies in PSQ-granites far from the main plane of faults; the scale, shape, occurrence and continuity were different between major and subordinate orebodies.1.1.5 The major orebodies had side-dip regulation in Jiaojia belt. If the belt dipped in NW-direction the orebodies in it would side-dipped in SW-direction; if the belt dipped in SE-direction the orebodies in it would side-dipped in NE-direction. In side-dip direction the orebodies possessed the characteristics of tip-disappear to appear and separate to composite.1.1.6 The major deposits (bodies) occurred in main faults of the belts distributed in equal-distance regulation along the faults and matched subordinate deposits (bodies) invertical direction to the faults.1.2 Geophysical Prospecting ModelThe geophysical prospecting models of gold bodies occurred in four type wall-rocks can be determined by combination of four-single geophysical models and each type of geophysical models can be generalized as following:1.2.1 The gold bodies occurred in fractured contact zones between plagioclase-amphibolites and Linglong granites, the model was as following: gradient belt from low to high for gravity and magnetism, companying low value; and high induced polarization value and sub-high resistivity.1.2.2 The gold bodies occurred in fractured contact zones between plagioclase-gneiss and Linglong granites, the model was as following: gradient belt from high to low for gravity and from low to high for magnetism, companying low value; and high induced polarization value and sub-high resistivity.1.2.3 The gold bodies occurred in fractured zones between Linglong granites and Guojialing granites, the model was as following: lower value for gravity, small gradient belt for magnetism; and high induced polarization value and low resistivity.1.2.4 The gold bodies occurred in fractured zones of Linglong granites, the model was as following: low for gravity and magnetism; and high-induced polarization value and low resistivity.1.3 Geochemical Prospecting ModelAccording to the characteristics of secondary and original haloes, the geochemical prospecting models can be determined as following:1.3.1 The secondary halo prospecting model. The secondary anomaly characteristics of gold bodies were mainly effected by location of their denudation plane and soil thinkness.when the bodies were denuded, in residual deposits (C-player soil) the elements combination of secondary anomaly were complicated, anomaly large, intensity high. When the gold bodies were denuded, in residual deposits (A2-player soil) the elements combination of secondary anomaly were simple (mainly as Au and Ag), intensity belts can be classified inner, intermediate and outer belt. When the gold bodies were concealed, in residual deposits (A2-player soil) the elements of secondary anomaly were mainly Au, intensity belts commonly as outer belt.1.3.2 The original halo prospecting model. The original halo elements of alternated rocks were very complicated and their major indicating elements were Au, Ag, As, Cu, Pb, Zn, Sb and Bi. The original halo characteristic was different between main faults and subordinate faults. Pb and Zn anomalies of the bodies occurred in main faults were positive anomaly and negative anomaly in subordinate faults.The elements along gold-bodies possessed the sequence from up to down as Sb-As-Cu-Bi-Au- Ag-Pb-Zn. The elements combinations were, different between before-gold-bodies.and after-gold-bodies. The combination of before-gold-bodies mainly were As,Sb,Cu and Bi and after-gold-bodies Ag,Pb and Zn. The elements combinations of the gold bodies in the contacts of granites and contacts between granites and Jiaodong group possessed unique difference. The anomalies of Au,K and Na still developed in the area of 500m far from gold bodies in advance.2. Outline of Metallogenic PredictionAccording to the prospecting models, intermediate-large scale gold deposits (bodies) prediction had been carried out in Jiaojia belt, which mainly included the deep parts of Jiaojia faults,Wangershan faults and Hexi faults.The results were as following: 11 intermediate-large scale prediction targets (25 orebodies) had been determined. The total predicted gold resource was 565 tons, which was 150% of the ascertained resource in the belt.From the mineral prediction and study we concluded that detail metallogenic regularities study played key role and geophysical, geochemical and remote sense image studies supplementary role. This Prediction method needn't take a lot personnel, time, and financial capacity; and could simply and accurately determined orebodies space, roughly calculated mineral resources and realized prediction aim. It could get f twice the result with half the effort and be one of the most effective methods in large-scale deep-space metallogenic prediction for exploration units.3.Discusion to Method of Large-Scale Deep-Space Metallogenic Prediction3.1 Geological Materials CollectionCollecting every kind of geological materials over the years, which include regional geological survey, mineral resources exploration, geophysical survey and geochemical survey materials; especially paying attention to deep-space geological material.3.2 Field Survey and StudyField survey and study should be conducted and detailed geological survey and recording to being mined in large scale, typical, deep mining depth mines paid special attention; which could identify their reliability and correctness of the collected geological materials and recognization of metallogenic regulation, and could provide newly and reliable geological material for metallogenic regularities study.3.3 Deposit's Geology StudyConducting the study on regional metallogenic model and ore-controlling geological condition; determining the contribution of strata, tectonic and magma to mineralization. Analyzing typical deposits in prediction area, thoroughly detailed studying on deposits (orebodies) occurrence regularities which include deposit's (orebodie's) distribution in equal-distance regularities, matching regularities between the major deposits (bodies) and subordinate deposits (bodies), matching relationship between fault's occurrence variation and deposits (orebodies), deposit's (orebodie's) shape's variation regularities, deposit's (orebodie's) side-dip regularities, deposit's (orebodie's) shape's tip-disappear to appear regularities, and mineralization zoning and enriching regularities.3.4 Geophysical and Geochemical Materials ProcessingAccording to criterion and adopting MAPGIS technical platform, the geophysical and geochemical materials were vectored by scanning and layering and the geological graph database constructed. Using advancedly automatic minerals prediction system, such as Dongshi Hisense Minerals Prediction System, the geophysical and geochemical materials were multiply processed. It could provide basis for lithological characters; deduce fault's location, property and deeply stretching; circle anomalies and determine their space relation between anomalies and induced polarized bodies; and clear relation between variation of indicative elements and orebodies.3.5.According to exploration documents and study on the deposits (orebodies) in...