地质学报
地質學報
지질학보
ACTA GEOLOGICA SINICA
2014年
4期
612-619
,共8页
胡英才%李桐林%范翠松%王大勇%李建平
鬍英纔%李桐林%範翠鬆%王大勇%李建平
호영재%리동림%범취송%왕대용%리건평
铜矿%复电阻率%可控源音频大地电磁法%接触带%辉石闪长岩%安徽铜陵舒家店
銅礦%複電阻率%可控源音頻大地電磁法%接觸帶%輝石閃長巖%安徽銅陵舒傢店
동광%복전조솔%가공원음빈대지전자법%접촉대%휘석섬장암%안휘동릉서가점
copper deposit%CR%CSAMT%contact zone%pyroxene diorite%Shujiadian,Tongling,Anhui Province
安徽铜陵地区是长江中下游铜-金-铁-硫成矿带内的一个重要成矿区,成矿类型主要为矽卡岩和热液型,成矿作用与岩浆岩活动密切相关,而舒家店斑岩型铜矿是近年来在该地区新发现的矿床类型,矿体主体主要赋存在靠北西接触带的岩体中,铜矿化与舒家店辉石闪长岩密切相关。针对该类型矿床开展的电磁法找矿有效性试验对本地区寻找同类型的矿床具有重要意义。本文首先在该矿区开展了可控源音频大地电磁测深和复电阻率两种电磁法野外测量工作,接着对两种试验的数据进行反演,并结合该区地质与钻孔资料对剖面进行了地质解释。CSAMT反演结果基本反映了该矿区的地电结构,电阻率从高到低依次为:花岗闪长斑岩、闪长岩、辉石闪长岩、石英闪长斑岩和志留系下统坟头组砂岩及粉砂岩地层。铜矿体位于高阻(闪长岩)和低阻(辉石闪长岩)的过渡带上,处于高阻闪长岩的右侧。虽然CSAMT的结果不能直接反映铜矿体,但可以通过追踪 CSAMT 各线中高阻体的位置来大致推测矿体的存在位置与走向。复电阻率法获得了零频电阻率,极化率,时间常数和频率相关系数4个反演断面图。在零频电阻率反演断面图中,辉石闪长岩电阻率表现中等,花岗闪长斑岩和闪长岩的电阻率比较高,这与CSAMT反演的结果相同。在矿体处,电阻率表现较小,极化率中等,时间常数和频率相关系数较大。本文最后得出如下结论:可控源音频大地电磁测深能够获得深部电阻率结构,对找矿提供间接信息,而复电阻率法通过反演的零频电阻率、极化率、频率相关系数和时间常数可以为斑岩型铜矿提供直接找矿信息。
安徽銅陵地區是長江中下遊銅-金-鐵-硫成礦帶內的一箇重要成礦區,成礦類型主要為矽卡巖和熱液型,成礦作用與巖漿巖活動密切相關,而舒傢店斑巖型銅礦是近年來在該地區新髮現的礦床類型,礦體主體主要賦存在靠北西接觸帶的巖體中,銅礦化與舒傢店輝石閃長巖密切相關。針對該類型礦床開展的電磁法找礦有效性試驗對本地區尋找同類型的礦床具有重要意義。本文首先在該礦區開展瞭可控源音頻大地電磁測深和複電阻率兩種電磁法野外測量工作,接著對兩種試驗的數據進行反縯,併結閤該區地質與鑽孔資料對剖麵進行瞭地質解釋。CSAMT反縯結果基本反映瞭該礦區的地電結構,電阻率從高到低依次為:花崗閃長斑巖、閃長巖、輝石閃長巖、石英閃長斑巖和誌留繫下統墳頭組砂巖及粉砂巖地層。銅礦體位于高阻(閃長巖)和低阻(輝石閃長巖)的過渡帶上,處于高阻閃長巖的右側。雖然CSAMT的結果不能直接反映銅礦體,但可以通過追蹤 CSAMT 各線中高阻體的位置來大緻推測礦體的存在位置與走嚮。複電阻率法穫得瞭零頻電阻率,極化率,時間常數和頻率相關繫數4箇反縯斷麵圖。在零頻電阻率反縯斷麵圖中,輝石閃長巖電阻率錶現中等,花崗閃長斑巖和閃長巖的電阻率比較高,這與CSAMT反縯的結果相同。在礦體處,電阻率錶現較小,極化率中等,時間常數和頻率相關繫數較大。本文最後得齣如下結論:可控源音頻大地電磁測深能夠穫得深部電阻率結構,對找礦提供間接信息,而複電阻率法通過反縯的零頻電阻率、極化率、頻率相關繫數和時間常數可以為斑巖型銅礦提供直接找礦信息。
안휘동릉지구시장강중하유동-금-철-류성광대내적일개중요성광구,성광류형주요위석잡암화열액형,성광작용여암장암활동밀절상관,이서가점반암형동광시근년래재해지구신발현적광상류형,광체주체주요부존재고북서접촉대적암체중,동광화여서가점휘석섬장암밀절상관。침대해류형광상개전적전자법조광유효성시험대본지구심조동류형적광상구유중요의의。본문수선재해광구개전료가공원음빈대지전자측심화복전조솔량충전자법야외측량공작,접착대량충시험적수거진행반연,병결합해구지질여찬공자료대부면진행료지질해석。CSAMT반연결과기본반영료해광구적지전결구,전조솔종고도저의차위:화강섬장반암、섬장암、휘석섬장암、석영섬장반암화지류계하통분두조사암급분사암지층。동광체위우고조(섬장암)화저조(휘석섬장암)적과도대상,처우고조섬장암적우측。수연CSAMT적결과불능직접반영동광체,단가이통과추종 CSAMT 각선중고조체적위치래대치추측광체적존재위치여주향。복전조솔법획득료령빈전조솔,겁화솔,시간상수화빈솔상관계수4개반연단면도。재령빈전조솔반연단면도중,휘석섬장암전조솔표현중등,화강섬장반암화섬장암적전조솔비교고,저여CSAMT반연적결과상동。재광체처,전조솔표현교소,겁화솔중등,시간상수화빈솔상관계수교대。본문최후득출여하결론:가공원음빈대지전자측심능구획득심부전조솔결구,대조광제공간접신식,이복전조솔법통과반연적령빈전조솔、겁화솔、빈솔상관계수화시간상수가이위반암형동광제공직접조광신식。
TheTongling area in Anhui province is one of the important deposits for Copper-Gold-Iron-Sulfur metallogenic belt in the middle and lower reaches of the Yangtze river.In this area,there are two main metallogenic types,the porphyry type and the hydrothermal type,and the mineralization is closely related with magmatic activities.Shujiadian porphyry copper deposit is a new type of copper deposit discovered in Tongling in recent years.The ore body is mainly aboudant in the rock mass which is adjacent to the north-west-contact-zone, and is closely related with the pyroxene diorite. The effective experiment of electromagnetic exploration method for this type of ore deposit is of great significance for searching the same type of deposit in this area.In this paper,Controlled Source Audio Magnetotelluric (CSAMT)and Complex Resistivity(CR)were firstly carried out,and then the measured data were inverted.Combined with geological and drilling data,we interpreted the inversion results.The CSAMT result basically reflects the geoelectric structure in this area. the corresponding resistivity, from high to low, is granodiorite-porphyry,diorite,pyroxene- diorite,quartz-diorite-porphyry,and sandstone and siltstone strata in the Silurian Fentou formation.The copper ore body is in the transitional zone from high resistivity (diorite)to low resistivity(pyroxene diorite)and is located on the right side of the diorite.Although the CSAMT result cannot directly give response to the copper ore body,it can roughly predict the position and trend of ore body according to the high resistivity(diorite)position in each line of the CSAMT result.It can obtainρ0 ,m,c,τparameters from complex resistivity method.In the results of zero frequency resistivity,the resistivity of pyroxene-diorite is medium,and the resistivity of granodiorite-porphyry and diorite are high,which have the same result with CSMAT,but in the ore body,zero frequency resistivity is relatively low,polarization coefficient is medium,frequency correlation coefficient and time constant are high.Finally, the following conclusions in this paper are that CSAMT can obtain deep resistivity structure,but it can not find porphyry copper deposit directly,Whereas,it can directly find the porphyry copper deposit usingρ0 ,m,c,τparameters obtained from complex resistivity method.