| Eastern Hebei-Western Liaoning area lies in the middle part of North China Plate’s northern rim, in the east part of Yan-Liao gold metallogenic belt, and also in the superposition part of Paleo-Asia ocean tectonic metallogenic area and Pacific West foreshore tectonic metallogenic area This area is in the complex affected zone of North China Rates, Siberian plate and Pacific plate. The geological evolution history of it ismuch long, and the diagenesis and metallogenesis in it is much complex. Especidly, the three large gold metallogenic concentration areas along "Two mountains and one anticline", forming in Mesozoic metallogenesis explosion, reflect the difference of metallogenic geological characteristics and the unity of metallogenesisBased on previous research results, this article focuses on five gold deposits, Jinchangyu, Yuerya, Jinchanggouliang, Erdaogou and Paishanlou, which are typical in the three large ore concentration areas. Through synthetical analysis and comparison on region metallogenic geological set of typical gold deposits, geological characteristics of deposits, fluid inclusion, stable isotope, rare-earth element, trace element, and lithogenetic and metallogenic period etc., metallogeic material origin, evolution and mineralization mechanism is researched, gold metallogenic dynamical mechanism and time-space evolution rules of main gold concentration area in Eastern Hebei-Western Liaoning is brought forward, region metallogenic mode is founded and metallogenic prediction is carried out. Metallogenic prediction on typical gold deposit, Paishanlou gold deposit, by methods of basic geology, geophysics and geochemistry, testified the efficiency and practicability of region metallogenesis and metallogenic prediction, and got the research results as follow:(1) Divide the gold occurrences in East Hebei-West Liaoning, which appear as’Two mountains and one anticline" around West Liaoning rift, into three gold deposit concentration areas:Ji nchangyu-Yuerya, Jnchanggouliang-Erdaogou and Paishanglou, the metallogenic geological characteristics of which are different. There into, two main mineralization types exist:quartz-vein type gold deposit and altered rock type gold deposit. Five medium to large typical gold deposits, Jinchangyu, Yuerya, Jinchanggouliang, Erdaogou and Paishanlou, are different in geological characteristics, but are similar in deep material origin, hydrothermal metal I ogeni c temperatures and metal I ogeni c process accordi ng to geochemi cal characteri sti cs. That, the deposit type and the local position of these five deposits are different i n apparent geological characteristics, means the specificality of metal I ogeni c position tectonic set defines the particularity and complexity of deposit type.(2)Basedon region tectonic evolution, divide the gold metal I ogeni c evolution in Eastern Hebei-Western Liaoning into five phases:(a) continent-continent collision-collage phase (4.5-1.85Ga), gold metal I ogeni c elements got preliminary enrichment;(b) intracontinental rifting sedimentary phase(1.85-0.6Ga), metallogeic materials were prepared for space distribution of Eastern Hebei-Western Liaoning gold deposits;(c) lifting period of intraplate orogenic extrusion phase(200-145Ma), main gold deposits of Ji nchangyu-Yuerya ore concentrated area in Eastern Hebei formed;(d) the transformation phase of tectonic regime (145-100Ma), gold metallogenesisof Eastern Hebei-Western Liaoning outbreak, large metal accumulated. That’s the main metallogenic period of Jinchanggouliang-Erdaogou ore concentrated area and Paishanlou ore concentrated area (e) post-mineralization modification period(200Ma to now). Developed rifting basin should be emphasized, and transformation phase of tectonic regime and time-space evolution in mineralization period and post mineralization period should be ascertained, then the gold deposits in this area can be accurate positioned and evaluated.(3) Based on the unity, concentration and explosive characteristics of regional metallogenesis, founded regional metallogenic model, predicted regional metallogenic potential. As the different ore types, because of different local position, appear as different appearance geological characteristics and different genetic types. Then, Paishanlou gold deposit, which occurs in medium-deep structural setting, was chosen as emphasis for deep metallogenic prediction. Region-^deposit and depositâ†'region metallogeny, prospecting practice and predicting methods are organic bonded. (4) Find and prove two sets of dolomitic mylonite and two gold metallogenic belts in different directions in Raishanlou gold deposit."Biotite-plagioclase protomylonite-^top dolomitic mylonite-gold oreâ†'Biotite-plagioclase mylonite and felsic mylonite" is the key mark of deposit position. From far to near ore, host rock zoning appears, as greening alteration zone-â†'carbonation alteration zoneâ†'Kfeldsparization alteration zoneâ†'yriteâ†'sericitization, that can help to decide whether there is deep gold mineralization.(5) Based on integrated deep prospecting prediction information technology, through basic geological information (stratum, structure, mineralization and alteration), geochemical trend field, deep penetration geochemistry (organic alkanetest, adsorbed Mercury and Radon test) and geophysical prospecting (high-precision magnetic survey and transient electromagnetic survey), seven prospecting targets has already been lined out in deep or periphery of Rai shanlou EW and NE metallogenic belts. And part of these targets has already been validated, considerable gold resource is identified and region gold deposit integrated deep prospecting predi cti on informati on technol ogy i s obtained. |
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