黑龙江多宝山斑岩铜矿赋矿岩体侵位深度及其对成矿的约束

The emplacement depth of ore-hosting rock body and its constraints on mineralization in Duobaoshan porphyry copper deposit,Heilongjiang Province

多宝山铜矿是中国北方著名的斑岩型矿床,许多学者对该矿床的成因、大地构造环境、成矿机制等进行了大量的研究,并取得较好的成果。但对矿床保存和后期改造尚缺研究,需要中低温热年代学研究控制矿床的剥蚀深度、阶段和时代,而含矿岩体的侵位深度是先决条件。为了准确确定多宝山铜矿含矿岩体的侵位深度,笔者选取赋矿花岗闪长斑岩体作为研究对象,并利用角闪石-斜长石地质温压计进行成矿深度分析。通过研究得出赋矿花岗闪长斑岩体成岩压力为1.69×10^(8)~1.78×10^(8)Pa,温度范围在650~710℃之间,成岩深度为6.36~6.69 km,对于研究矿床剥蚀深度及速率、演化阶段、构造背景等都具有重要的意义。

Duobaoshan copper deposit,a famous porphyry deposit in northern China,has been extensively studied on its origin,tectonic environment and metallogenic mechanism by many scholars,and significant advances have been achieved.In constrast,the preservation and later geological alteration of the deposit have been little researched.It is necessary to constrain the exhumation depth,metallogenic stage and age of the deposit using medium-low temperature thermochronology,in particular,the emplacement depth of ore-hosting rock body should be first known.In this study,in order to accurately determine the emplacement depth of the ore-hosting rock body in the Duobaoshan copper deposit,we have conducted study on the emplacement depth of the ore-hosting granodiorite porphyry body using hornblende-plagioclase geothermobarometer.The results show that the ore-hosting granodiorite porphyry body has the diagenetic pressure of 1.69×10^(8)~1.78×10^(8)Pa,the diagenetic temperature of 650~710℃and the emplacement depth of 6.36~6.69 km,this is of great significance for studying the depth and rate of exhumation,evolution stage,and tectonic environment of this deposit.