吉林大学学报（地球科学版）
吉林大學學報（地毬科學版）
길림대학학보（지구과학판）
JOURNAL OF JILIN UNIVERSITY(EARTH SCIENCE EDITION)
2015年
1期
119-131
,共13页
地质学%Re Os 同位素%辉钼矿%成矿年龄%连城铜坑钼矿床%福建
地質學%Re Os 同位素%輝鉬礦%成礦年齡%連城銅坑鉬礦床%福建
지질학%Re Os 동위소%휘목광%성광년령%련성동갱목광상%복건
geology%Re Os isotope%molybdenite%metallogenic age%Tongkeng molybdenum deposit in Liancheng%Fujian
福建连城铜坑钼矿床是近年来在闽西南地区找到的又一处钼矿床。钼矿化在铜坑燕山晚期第一阶段花岗斑岩岩体与晚古生界变质岩接触带内呈浸染状、脉状、透镜状等形态产出。本次研究过程中,对6件代表性辉钼矿样品进行了 Re Os 同位素年龄测定,Re Os 同位素模式年龄值为115.1~116.7 Ma,等时线年龄为(115.7±1.1)Ma,由此认为铜坑钼矿床与花岗斑岩的形成时间均为早白垩世,属燕山晚期构造岩浆活动的产物。结合矿区外围其他钼矿床同位素年龄数据可以推测,闽西南坳陷燕山早期大规模钼矿化发生在印支期稳定的台地向活动大陆边缘转变阶段并伴随燕山早期挤压隆升(160~145 Ma),燕山晚期由挤压向拉张机制转换(125~105 Ma)的构造改造阶段所诱发的岩浆活动是导致钼矿床形成的主导因素。
福建連城銅坑鉬礦床是近年來在閩西南地區找到的又一處鉬礦床。鉬礦化在銅坑燕山晚期第一階段花崗斑巖巖體與晚古生界變質巖接觸帶內呈浸染狀、脈狀、透鏡狀等形態產齣。本次研究過程中,對6件代錶性輝鉬礦樣品進行瞭 Re Os 同位素年齡測定,Re Os 同位素模式年齡值為115.1~116.7 Ma,等時線年齡為(115.7±1.1)Ma,由此認為銅坑鉬礦床與花崗斑巖的形成時間均為早白堊世,屬燕山晚期構造巖漿活動的產物。結閤礦區外圍其他鉬礦床同位素年齡數據可以推測,閩西南坳陷燕山早期大規模鉬礦化髮生在印支期穩定的檯地嚮活動大陸邊緣轉變階段併伴隨燕山早期擠壓隆升(160~145 Ma),燕山晚期由擠壓嚮拉張機製轉換(125~105 Ma)的構造改造階段所誘髮的巖漿活動是導緻鉬礦床形成的主導因素。
복건련성동갱목광상시근년래재민서남지구조도적우일처목광상。목광화재동갱연산만기제일계단화강반암암체여만고생계변질암접촉대내정침염상、맥상、투경상등형태산출。본차연구과정중,대6건대표성휘목광양품진행료 Re Os 동위소년령측정,Re Os 동위소모식년령치위115.1~116.7 Ma,등시선년령위(115.7±1.1)Ma,유차인위동갱목광상여화강반암적형성시간균위조백성세,속연산만기구조암장활동적산물。결합광구외위기타목광상동위소년령수거가이추측,민서남요함연산조기대규모목광화발생재인지기은정적태지향활동대륙변연전변계단병반수연산조기제압륭승(160~145 Ma),연산만기유제압향랍장궤제전환(125~105 Ma)적구조개조계단소유발적암장활동시도치목광상형성적주도인소。
Located in the southwestern Fujian Province,the Tongkeng ore deposit in Liancheng is a newly discovered molybdenum deposit.The molybdenum mineralization occurs within the contact zone between the granite porphyry stock formed in the first stage of late Yanshanian magmatic event in Tongkeng area and late Paleozoic metamorphic rocks.Ore bodies are charactered by vein,veinlet and disseminated.Re Os dating of six molybdenite samples collected from the major ore body shows that the isochron age is (1 15.7 ±1.1 )Ma and the model ages range from 1 15.1 Ma to 1 1 6.7 Ma,with an average value of (1 15.8±0.8)Ma.It can be considered that both the granite-porphyry and associated molybdenum mineralization were formed in Early Cretaceous,and that both were derived by the late Yanshanian tectonic-magmatic event in the southwestern Fujian depression.Combined with isotopic age data from other adjacent molybdenum deposits,it can be inferred that the early Yanshanian large-scale molybdenum mineralization in the southwestern Fujian depression formed during the transition stage from the Indosinian sustained platform to active continental margin,and accompanied by compressing and uplifting in early Yanshanian (about 1 60 145 Ma);the late Yanshanian tectonic conversion from compressing to tension (about 125 105 Ma)resulted in the magmatism which seemed to be the dominant factor for the late Yanshanian molybdenum deposit.
