西北地质
西北地質
서북지질
NORTHWESTERN GEOLOGY
2014年
3期
26-34
,共9页
矿床地球化学%成矿作用%斑岩铜钼矿%成矿模式%纳日贡玛%青海南部
礦床地毬化學%成礦作用%斑巖銅鉬礦%成礦模式%納日貢瑪%青海南部
광상지구화학%성광작용%반암동목광%성광모식%납일공마%청해남부
geochemistry of mineral deposits%mineralization%porphyry Cu-Mo deposit%metallogenic model%Narigongma%Southern Qinghai
纳日贡玛矿床是我国著名“三江”北段成矿区带中最典型的斑岩型 C u-Mo 矿床。在总结矿床地质特征的基础上，通过系统总结该矿床的矿床地球化学及成矿作用相关资料，得出以下结论：①纳日贡玛矿床形成于喜马拉雅运动早期，纳日贡玛铜钼矿床成矿物质主要来自花岗斑岩体，成矿花岗斑岩源于下地壳；成矿流体为岩浆期后热液，矿床硫是由岩浆硫(为主)和成矿流体萃取围岩中的硫所组成的1种混合硫源。矿床的形成与青藏高原东缘区域构造和应力转换密切相关。②基于已有认识，建立了纳日贡玛铜钼矿床的成矿理想模式，认为矿体形成背景可能为逆冲挤压推覆条件下的局部拉张环境，拉张降压以及围岩的性质导致了该矿床富钼贫铜现况；矿床热液蚀变发育，绢云岩化与矿体较为密切，钾化带范围小，与成矿关系不大；纳日贡玛矿区剥蚀程度大，纳日贡玛矿床东南部剥蚀程度相对较小，在东南部外围找矿过程中，应该兼顾矽卡岩型矿体。
納日貢瑪礦床是我國著名“三江”北段成礦區帶中最典型的斑巖型 C u-Mo 礦床。在總結礦床地質特徵的基礎上，通過繫統總結該礦床的礦床地毬化學及成礦作用相關資料，得齣以下結論：①納日貢瑪礦床形成于喜馬拉雅運動早期，納日貢瑪銅鉬礦床成礦物質主要來自花崗斑巖體，成礦花崗斑巖源于下地殼；成礦流體為巖漿期後熱液，礦床硫是由巖漿硫(為主)和成礦流體萃取圍巖中的硫所組成的1種混閤硫源。礦床的形成與青藏高原東緣區域構造和應力轉換密切相關。②基于已有認識，建立瞭納日貢瑪銅鉬礦床的成礦理想模式，認為礦體形成揹景可能為逆遲擠壓推覆條件下的跼部拉張環境，拉張降壓以及圍巖的性質導緻瞭該礦床富鉬貧銅現況；礦床熱液蝕變髮育，絹雲巖化與礦體較為密切，鉀化帶範圍小，與成礦關繫不大；納日貢瑪礦區剝蝕程度大，納日貢瑪礦床東南部剝蝕程度相對較小，在東南部外圍找礦過程中，應該兼顧矽卡巖型礦體。
납일공마광상시아국저명“삼강”북단성광구대중최전형적반암형 C u-Mo 광상。재총결광상지질특정적기출상，통과계통총결해광상적광상지구화학급성광작용상관자료，득출이하결론：①납일공마광상형성우희마랍아운동조기，납일공마동목광상성광물질주요래자화강반암체，성광화강반암원우하지각；성광류체위암장기후열액，광상류시유암장류(위주)화성광류체췌취위암중적류소조성적1충혼합류원。광상적형성여청장고원동연구역구조화응력전환밀절상관。②기우이유인식，건립료납일공마동목광상적성광이상모식，인위광체형성배경가능위역충제압추복조건하적국부랍장배경，랍장강압이급위암적성질도치료해광상부목빈동현황；광상열액식변발육，견운암화여광체교위밀절，갑화대범위소，여성광관계불대；납일공마광구박식정도대，납일공마광상동남부박식정도상대교소，재동남부외위조광과정중，응해겸고석잡암형광체。
The Narigngma deposit is a typical porphyry Cu-Mo deposit located in the north metallogenic belt of Sanjiang Plain.Based on the features of Narigongma deposit,and through a systematic summary of the deposit geochemistry characteristics as well as mineralization information,following results are obtained:① The Narigongma deposit formed in the early Himalayan movement.The metallogenic material was mainly composed of granitic porphyry from lower crust.The ore-forming fluids derived from magmatic hydrothermal.The sulfur in the deposit is originated from a mixed sulfur source that consisted of magmatic sulfur (mainly)and the extracted sulfur by ore-forming fluid from the adj acent rock.Deposit formation is related to transformation of regional tectonic and stress of eastern margin of the Tibetan Plateau.② Based on the results,an ideal metallogenic model of Narigongma Cu-Mo deposit is established,and it is considered that the deposit forming background may be partial extensional environment under thrust nappe squeezed conditions. The tensile antihypertensive and the properties of the surrounding rock caused the current situation of rich-molybdenum and poor-copper. Hydrothermal alteration is developed in the deposit,and sericitization is closely related to ore body,while the potassic alteration range is small,having little relationship with mineralization. The erosion degree of Narigongma mining area is strong,while the erosion degree in southeast of Narigongma deposit is relatively small.So in the peripheral exploration process,we should take into account the skarn-type ore bodies.
