| The paper is on the base of items, which are “Resource evaluation of FuJiagoumolybdenum gold deposit project in NingShan county of shaanxi province”,“The research ofstructure and evaluation method of quickly prospecting in Shaanxi Hanyin Tiefo-HanBin areaSilurian System’s rock gold ore fieldand so on. Select the Ore-controlling fracture which is NE-NNE trending formed in Late Triassic-Early Yanshanian in East Qinling Ning Shaanxi-Zhen’an. Through the comprehensive analysis to the regional tectonic-magmatic evolution,fieldwork of gold molybdenum ore deposits affected by such faults, Analysis discusses itscauses, metallogenic characteristics, access to the following main understanding:1. This area in Late Triassic-Early Yanshanian experienced orogenic collapse of"four-dimensional space-time from deep to shallow gradually collapse". In the middle-lateYanshanian massive compression and shortening the region happened, and it tended tointracontinental orogenic phase.In the early evolution of Collapsed, abnormal thickeninglithosphere range first began to intense collapse adjustment and induce magmatism. Intrusionof magma formed and developed the region Wulong, dongjiangkou, rouge dam and Pali PingChao unit. They are generally formed at about233-190Ma. In the middle-late evolution ofcollapse, with the rise of magma’s emplacement and shallow tectonic regime transition fromcompression to extension, trigger the lower crust rapid uplift formation Foping dome. Theregion developed thrust fault which is EW trending in the process of collision orogeny andmany different sizes of North East-North East trending sinistral strike-slip faults whichformed in the Early to Middle Jurassic and controled by Foping dome uplift, magma arch andorogenic left-slip rheology overall in the formation.2. Magmatic activity can be roughly divided into five emplacement process from thetime since the indosinian period of the study area. It has the characteristic of north east todistribution from the space and has the trend of moving to north and east from the space-timefour-dimensional changes. Existing research shows that: deep in foping area is a magmaticactivity center in the process of qinling orogenic collision. Infer that area there may be a northeast to the extension of crust-mantle mixed molten lava channel, deep magma upwells alongthe channel and forms a series of intrusive mass which has the characteristics of periodicityand moving to north and east.3. Stage of collapse evolution of orogenic belts of the Late Triassic-early Yanshan period,especially late collapse evolution, is an important large-scale mineralization period. Plenty ofgold, molybdenum deposits was formed during the stage. Many gold deposit which formed in this phase and has been found in the region have the feature of NE-NNE ore-controllingfracture, roughly formed in early middle Jurassic. This kind of phenomenon may representsthat a hydrothermal ore-forming event happened in the aera which has the feature of NE-NNEore-controlling fracture, it is worth be highly attended in the ore exploration. Molybdenummineralization is directly related to late Triassic magmatic activities, especially the Yanzhibarock mass. Ore types are mainly skarn type, which was mainly founded in the contact zone ofthe Yanzhiba pluton and the surrounding rock of the Palaeozoic strata. Quartz vein typemolybdenum deposit was also can be founded and controlled by the NE-NNE fracture. |
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