CAJ | 학술논문

通过对南祁连山党河南山东段乌里沟金矿区中酸性侵入岩锆石 U-Pb 年龄测定及岩石地球化学分析，探讨了岩体形成的构造环境及其与金矿成矿的关系。矿区角闪石闪长岩体侵位年龄为457±6．3 Ma，岩石中各组分的质量分数：SiO2为48．98％～59．16％，Al2 O3为14．51％～16．77％，K2 O＋Na2 O 为8．24％～9．47％，属准铝质、碱性－过碱性岩系列；DI 为58～79，属 I 型花岗岩类；岩石 Cr 和 Mg＃值较低，Na2 O 和 K2 O 含量接近，表明源岩含有较多的壳源成分；稀土总量中等，轻稀土富集，具弱 Eu 负异常；相对富集大离子亲石元素 Rb、Ba、Th、K、U，亏损 Nb、Ta、P、Ti。矿区二长花岗岩属碱性岩系列，比角闪石闪长岩稀土总量低、更加亏损 Nb、Ta 等，与角闪石闪长岩属同一岩浆源，分异程度比角闪石闪长岩高。两种岩石均具岛弧岩浆岩特征，是中晚奥陶世南祁连俯冲到较浅部位熔融形成。岩体金含量高，目前探明的矿体产于岩体内部及接触带，围岩蚀变强烈，显示岩体为金矿成矿提供物质来源和成矿热液。
통과대남기련산당하남산동단오리구금광구중산성침입암고석 U-Pb 년령측정급암석지구화학분석，탐토료암체형성적구조배경급기여금광성광적관계。광구각섬석섬장암체침위년령위457±6．3 Ma，암석중각조분적질량분수：SiO2위48．98％～59．16％，Al2 O3위14．51％～16．77％，K2 O＋Na2 O 위8．24％～9．47％，속준려질、감성－과감성암계렬；DI 위58～79，속 I 형화강암류；암석 Cr 화 Mg＃치교저，Na2 O 화 K2 O 함량접근，표명원암함유교다적각원성분；희토총량중등，경희토부집，구약 Eu 부이상；상대부집대리자친석원소 Rb、Ba、Th、K、U，우손 Nb、Ta、P、Ti。광구이장화강암속감성암계렬，비각섬석섬장암희토총량저、경가우손 Nb、Ta 등，여각섬석섬장암속동일암장원，분이정도비각섬석섬장암고。량충암석균구도호암장암특정，시중만오도세남기련부충도교천부위용융형성。암체금함량고，목전탐명적광체산우암체내부급접촉대，위암식변강렬，현시암체위금광성광제공물질래원화성광열액。
This paper reports the zircon U-Pb dating and the lithogeochemistry of the small-scale neutral-acidic intrusions in the Wuligou gold deposit in the east of Danghenanshan,South Qilian Mt., and interprets their tectonic settings and the linkage to gold mineralization.Our data show that the emplacement age of the amphibole diorite is 457 ±6.3 Ma.The mass fraction of SiO2 is 48.98% ~59.16%,that of A1 2 O3 is 14.51%~16.77%,that of (K2 O+Na2 O)is 8.24%~9.47% and that of DI is 58 ~ 79,indicating that the amphibole diorite belongs to the ultra-alkaline to alkaline,sub-aluminous rock series and I-type granitoid rocks.The amphibole diorite is poor in Cr and has low value of Mg# ,suggesting that its source rock has many crust materials.The total REE is moderate and LREE is rich,with slightly negative Eu abnormity.The large ion lithophile elements of Rb,Ba, Th,K,U are relatively rich and Nb,Ta,P,Ti are poor.The monzonitic granite belongs to the alkaline rock series,and its total REE is lower than that of the amphibole diorite and its Nb and Ta are more poor. These two types of rocks are originated from the same magma source. The differentiation of the monzonitic granite is higher than that of the amphibole diorite.They have geochemical characteristics of the island arc magmatic rock,and formed in the island arc when the north margin of Qaidam subducted beneath South Qilian during middle-late Ordovician.The Wuligou gold deposit is temporally and genetically related to the intrusions,because the alternation and the mineralization occur in the intrusion’s contact zones,and the Au content is extremely higher than that in the crust.All these show that the intrusions provide both the metallogenic materials and the thermal fluids for the formation of the gold deposit.