Prediction On Gold Deposit Resources On The Right Bank Of The Heilongjiang River

Located at Mohe County, Tahe County, Huma County, Heihe City, Sunwu Countyand Nenjiang County in the northwestern and northern part of Heilongjiang Province, golddeposit belt along the right bank of the Heilongjiang River (Mohe-Luobei Section) has alength of about500km and a depth of approximately80km, which presents a shape ofstair steps along a belt area from north to west and covers an area of about40000km2. Theresearch area is located in the north-east Section of Khingan-Mongolian orogenic belt,Erguna massif and terrigenous accretion tectonic zone in Greater Khingan Mountainsformed in early Paleozoic Era. The area belonged to Paleo-Asian Ocean tectonic domainin Pre-Mesozoic Era and the marginal Pacific Ocean tectonic domain starting fromMesozoic Era. It is believed based on researches that this area has metallogenic prospectfor precious metal deposits and huge potential for resources[5].This research subject serves as a component of a project for national evaluation onpotential of mineral resources, namely Evaluation on Potential of Mineral Resources inHeilongjiang Province (Project No.1212010881613). In this research, various theoriesand methods for metallogenic prediction are analyzed and comprehensive informationinterpretation method is used to interpret geophysical data and geochemical data about thenorthern part of Heilongjiang Province. In addition, geophysical and geochemicalcharacteristics of the research area are understood, and geophysical and geochemical dataare extracted. Based on results of previous geological researches, geological phenomena or geological bodies in the research area are deduced, which makes a contribution for theimprovement of level of geological researches on the area. In this research, comparativestudy on geological conditions for metallogenic province of gold deposit is conducted andmetallogenic prediction model is established through result of comprehensiveinterpretation and typical mineral resources. Key point of this research is to predict goldmine resources along the right bank of the Heilongjiang River and locate possible mindfields, which can provide a basis for reference regarding further mineral exploration in thepredicted area.In this research, some useful results are achieved in the aspects of geologicalbackground of metallogenic province, comprehensive interpretation of geophysical dataand prediction on precious metal deposit.1. Geological Background of Mineral ProductsThe northern part of Heilongjiang Province is located in the eastern part of Tianshan-Khingan-Mongolian orogenic belt (Level-I geotectonic element). Level-II geotectonicelements involved in prediction on gold deposit are back-arc basin system in GreaterKhingan Mountains (central and eastern part) and magmatic arc massif from LesserKhingan Mountains to Zhangguangcai Mountains. Faulted structures in the area aremainly (exposed and hidden) basement edges and east-west and north-east deeply faultedstructure with the characteristic of multi-stage activities, which controlled spacedistribution of magmatic rocks and has direct control over gold mineralization togetherwith associated or derived faulted structures from east to west, approximately from east towest and from north to east. Turning zone of faulted structures and intersection ofmulti-group structures are favorable places for mineralization.Stratums include those formed in the period from Neoproterozoic Era to LowerCambrian Era, Lower Paleozoic Era, Upper Paleozoic Era, Mesozoic Era and CenozoicEra. Volcanic rocks can be categorized into marine volcanic rocks and continental volcanicrocks based on genesis and environment. Intrusive rocks are located at the northeasternend of Tianshan-Khingan-Mongolian orogenic belt, where magmatic intrusion activitiesare frequent and violent. Such magmatic intrusion activities mainly occurred in Proterozoic Era, Paleozoic Era and Mesozoic Era and lithological characters of the areaare relatively complicated, which are mainly neutral and acid rocks. Based on the spatialcorrelation between geotectonic elements and distribution of intrusive rocks, the area canbe divided into two magmatic arcs from north to south, namely Erguna magmatic arc andDuobaoshan island arc. Metamorphic rocks in the northern part of Heilongjiang Provinceare mainly distributed in Greater Khingan Mountains, Lesser Khingan Mountains andZhangguangcai Mountains, which formed crystalline basement in various zones.2. Comprehensive Interpretation of Gravitational and Aeromagnetic DataThe research are is divided into three magnetic field zones from north to south,including smooth magnetic field zone, complicated magnetic field zone and alternatingmagnetic field zone, which indicates that magnetism is characterized by distribution fromeast to west and changing from south to north.Geological factors caused by positive and negative field sub-zones of smoothmagnetic field zone may be: Negative magnetic anomaly is caused by Jurassic stratum ofMesozoic Group in foreland basin. Positive magnetic anomaly is caused by cretaceousvolcanic rock stratum of Mesozoic Group in foreland basin. Positive magnetic fieldsub-zone in smooth magnetic field zone is caused by neutral and acid rock arcs in Ergunaisland arc. Positive field sub-zone of complicated magnetic field zone is caused byvolcanic rock stratum and neutral and acid intrusive rocks. Sub-zone of strong positivemagnetic field is jointly caused by neutral and acid rocks formed during Neo-ProterozoicEra, Late Triassic Era and later period of early Jurassic Era.Faulted structure system in the research area is deduced from the perspective ofmagnetic field and expressed in maps. Vertical magnetism is characterized by successionand layering, and boundary line occurs between8100m and16200m.The research area is divided into6gravitational field zones, namely gravity gradientzone along the river, Huzhong Town-Xinglong County complicated gravitational fieldzone, Nuomin-Jiagedaqi gradient zone, Heihe-Nenjiang complicated gravitational fieldzone, Sunwu complicated gravitational field zone and Nehe-Ping’an calm gravitational field zone. Gravity gradient zone is caused by faulted structure and gravity gradient zonealong the river is gravitational reaction caused by the existence of Heilongjiang fault zone.There may be a south-north faulted structure belt from Jiagedaqi to Nuomin and itscharacteristics are to be explored. Complicated magnetic field zone from Huzhong Townto Xinglong Town is characterized by relatively lower gravity; while complicatedmagnetic field zone from Heihe to Nenjiang is characterized by relatively higher gravity,which coincides with the division scheme for Level-III geotectonic elements described inworks of Han Zhenxin and other people.Correlation among faulted structures deduced through gravity and magnetismindicates that faulted structure system has the following characteristics: East-west andnorth-east faulted structures were formed earlier in multi-stage activities; while north-westfaulted structures were formed later, which serve as the main controlling structure ofvolcanic rocks in Greater Khingan Mountains. Faulted structures are distributed in aregional pattern, including Yixiken-Mohe Country-Huzhong Town faulted structure zone,Huma County-Jiagedaqi faulted structure zone and Heihe City-Wudalianchi City faultedstructure zone.3. Regional Prediction ModelThree regional prediction models for gold mine are constructed based on typicalprecious metal deposits and the relation between geotectonic elements (Level-III) andmineral deposits. Shabaosi-type model is a regional prediction model for gold deposit inforeland basin related to magmatic activities in Mohe, which is applicable for predictionof gold deposit in foreland basin in Mohe and Erguna island arc. Pangkaimen-type modelis a regional prediction model for gold deposit in Huma back-arc basin related to magmaticactivities. Sandaowanzi-type model is a regional prediction model for gold deposit inDuobaoshan island arc related to magmatic activities, which is applicable for prediction ongold deposit in Duobaoshan island arc and mixed tectonic belt from Keluo to Heihe. Aregional prediction model for lead-zinc polymetallic deposits is constructed, which providesa theoretical basis for prediction of polymetallic deposits in Erguna island arc area. 4. Prediction on Gold DepositIt is indicated in geochemical exploration that area of catchment basin for gravelmine resources is controlled by exposed and hidden basement. Metallogenic materials ingravel mine are mainly composed of basement metamorphic rocks, Mesozoic volcanicrocks and intrusive granites. Rock and gravel mineralization are associated, and rock-typegold deposits are located at the source of catchment basin for gravel mine or side-sourcecatchment basin. Upper reach of catchment basin is favorable for mineralization ofrock-type gold deposit, while middle reach and lower reach of catchment basin areprospective zones for locating gravel gold deposit. Statistic geological units are dividedbased on geochemical anomaly and catchment basin through geological unit method. Atotal of107statistic geological units are marked off in the research area, among which88units are precious metal units and19units are polymetallic units, based on which adistribution diagram of statistic geological units with a scale of1:500000is prepared.Based on3geological environment zones, estimation on connection degree among88statistic geological units of gold deposits is realized through digital model for featureanalysis and mineralization level of various units are analyzed. On the basis of suchanalysis, a prediction on the area of80km along the right bank of the Heilongjiang Riveris realized.Area along the right bank is divided into71units, among which45units are Level-Iunits,6units are Level-II units,11units are Level-III units and9units are Level-IV units. Itis indicated in the research that there is huge prospecting potential for gold deposit resourcesin the research area. Six prospective zones along the right bank are marked off, including3Type-A prospective zones,2Type-B prospective zones and1Type-C prospective zones,which provides a basis for arrangement of further prospecting of gold deposits.