CAJ | 학술논문

敖仑花钼矿床位于大兴安岭南段,是西拉木伦河断裂北侧多金属矿集区内新发现的斑岩型钼矿床.首次采用SHRIMP锆石U-Pb技术对敖仑花含矿花岗斑岩进行了测年,获得成岩年龄为134±4Ma;采用ICP-MS方法测定敖仑花钼矿床辉钼矿中Re-Os同位素,获得模式年龄在131±2～133±2Ma之间,辉钼矿Re-Os同位素等时线年龄为132±1Ma(MSWD=1.12),成岩与成矿误差范围内基本同时发生,敖仑花斑岩钼矿床为早白垩世构造、岩浆活动的产物.西拉木伦河断裂带内的多金属矿床具有一定的时空分布规律,130～150Ma是带内矿床成矿高峰期,两侧矿床可能具有不同的成矿物质来源.区内独特的成矿特征,与区域经历了古亚洲洋构造域和滨西太平洋构造域的复合演化有关,发生于早白垩世时期的这一大规模成矿事件,是该区经历增生造山和地壳加厚之后,演化为孤后大陆伸展背景时强烈岩浆活动和成矿作用的产物.
오륜화목광상위우대흥안령남단,시서랍목륜하단렬북측다금속광집구내신발현적반암형목광상.수차채용SHRIMP고석U-Pb기술대오륜화함광화강반암진행료측년,획득성암년령위134±4Ma;채용ICP-MS방법측정오륜화목광상휘목광중Re-Os동위소,획득모식년령재131±2～133±2Ma지간,휘목광Re-Os동위소등시선년령위132±1Ma(MSWD=1.12),성암여성광오차범위내기본동시발생,오륜화반암목광상위조백성세구조、암장활동적산물.서랍목륜하단렬대내적다금속광상구유일정적시공분포규률,130～150Ma시대내광상성광고봉기,량측광상가능구유불동적성광물질래원.구내독특적성광특정,여구역경력료고아주양구조역화빈서태평양구조역적복합연화유관,발생우조백성세시기적저일대규모성광사건,시해구경력증생조산화지각가후지후,연화위고후대륙신전배경시강렬암장활동화성광작용적산물.
Located in the southern segment of the Da Hinggan Mountains,the Aolunhua Mo deposit is newly found as a porphyry molybdenum deposit to the north of the Xilamulun fault.U-Pb dating for zircons from the Aolunhua granitic porphyry by SHRIMP method yields an age of 134±4Ma.Re-Os isotopic dating by the ICP-MS method on molybdenites separated from the Aolunhua molybdenum deposit yields an isochron age of 132±1Ma(MSWD = 1.12),with model ages ranging from 131±2 to 133±2Ma.The ore-forming time of the porphyry Mo deposit represented by the Re-Os isochron age is almost same as the time of petrogenesis,both in early Cretaceous.Our new age data,along with the published age data of the polymetallic deposits in the Xilamulun metallogenic belt,lead us to suggest that 130～150Ma is the main period of ore-formation in this area,and the ore-forming material for the deposits on both sides of the Xilamulun fault were from different sources.The unique metallogenic characteristics of the polymetallic deposits in the Xilamulun metallogenie belt was probably linked to the composite evolution of the Paleoasian and west circum-Paeifie tectonomagmatic domains.The main metallogenic pulse formed responding to the intensive magmatism and minerogenesis in early Cretaceous during which an extensional back-are regime was developed in the Xilamulun area following accretionary orogenesis and thickening of continental crust.