黑龙江四山林场金矿床闪长玢岩中锆石U——Pb 年龄及其地质意义

黑龙江四山林场金矿床是近年来在滨东地区发现的一座典型的硫化物石英脉型金矿。对其与成矿关系密切的闪长玢岩中锆石进行了详细研究的结果显示，该锆石的U--Pb 年龄可分为6 组: 1 057 ± 9 Ma、199 ± 2 Ma、144 ～ 148 Ma、115 ± 2. 7 Ma、111. 6 ± 1. 7 Ma ( n = 6，MSWD = 0. 55，probability = 0. 77) 和107. 3 ± 2. 8 Ma ( n = 3，MSWD = 0. 088，probability = 0. 92) 。结合区域岩浆热事件的发育状况，初步判定闪长玢岩的岩浆就位于115 ～ 107 Ma，岩浆演化过程受到中元古代及早侏罗世花岗质岩石的强烈混染; 成矿作用发生在早白垩世晚期向晚白垩世的转化阶段，其成岩成矿背景与太平洋板块俯冲作用下中酸性花岗岩岩浆作用密切相关。

Zircon LA-ICP-MS U--Pb dating of diorite-porphyrite from Sishanlinchang gold deposit in Heilongjiang and its geological significance

Sishanlinchang ore deposit is a typical gold deposit in sulfide quartz vein type,and found in Bindong area in recent years.The authors studied the zircon of diorite-porphyrite closely related to mineralization,which results show that the zircon U——Pb dating in diorite-porphyrite can be inducted six groups i.e.1 057±9 Ma,199±2 Ma,144~148 Ma,115±2.7 Ma,111.6±1.7 Ma（n=6,MSWD=0.55,probability=0.77）and 107.3 ±2.8 Ma（n=3,MSWD=0.088,probability=0.92）.Combined with considerations of the development of the regional thermal event of magma,the authors suggested that diorite magma emplaced in 115~107 Ma,and its evolution underwent the strong contamination by granitic rock in Mesoproterozoic and Early Jurassic.The mineralization occurred in the conversion stage from later Early Cretaceous to Late Cretaceous,and its metallogenetic and diagenetic background was related to mid-acid granitic magmatism by the subduction of the Pacific plate.