本文選題：巖石地球化學(xué) + O型埃達(dá)克巖　； 參考：《礦物巖石》2017年04期

【摘要】：三岔口銅礦床位于新疆東天山大南湖島弧帶的東北緣。目前對(duì)于三岔口銅礦床的成因類型及成礦年代還存在爭議。三岔口銅礦床中賦礦巖體為閃長巖-花崗閃長巖,發(fā)育黑云母化、硅化、絹英巖化、青磐巖化等。測得三岔口銅礦床輝鉬礦Re-Os年齡為416Ma±6.4 Ma,含礦閃長巖中鋯石LA-ICP-MS U-Pb年齡為425 Ma±3.9 Ma,反映該礦床形成于中志留世。礦區(qū)內(nèi)閃長巖-花崗閃長巖w(Na_2O+K_2O)為3.88%~4.68%,A/NCK值均大于1,為鋁飽和巖石。巖體貧鉀(w(K_2O)0.47%~1.18%)富鈉(w(Na_2O)_2.83%~4.23%),w(TiO_2)偏低(0.41%~0.46%),多屬于低鉀拉斑系列。巖體富集w(Ba)(260×10~(-6)~4 810×10~(-6)),w(Sr)(644×10~(-6)~797×10~(-6))等大離子親石元素,虧損w(Nb)(2.1×10~(-6)~2.6×10~(-6)),w(Ta)(0.1×10~(-6)),w(Zr)(11.2×10~(-6)~13.1×10~(-6))等高場強(qiáng)元素,具島弧巖漿巖的特征。巖體富Na貧K,K_2O/Na_2O0.42,且具有高w(Al_2O_3)(≥16.65%),w(SiO_2)(≥61.3%),w(Sr)(≥644×10~(-6))以及較低的w(Y)(≤13.7×10~(-6))和w(Yb)(≤1.41×10~(-6)),具O型埃達(dá)克巖的特征,表明三岔口銅礦床形成于俯沖島弧環(huán)境。結(jié)合研究區(qū)域內(nèi)銅(鉬)礦床的成礦時(shí)代及礦床類型,得出東天山地區(qū)有三期斑巖型礦床成礦作用:志留紀(jì)的三岔口、玉海斑巖型銅礦床,石炭紀(jì)的土屋-延?xùn)|、延西等斑巖型銅礦床,以及三疊紀(jì)的東戈壁、白山斑巖型鉬礦床。
[Abstract]:Sanchakou copper deposit is located in the northeast margin of the Dananhu island arc belt in East Tianshan, Xinjiang. At present, the genetic type and metallogenic age of Sanchakou copper deposit are still controversial. The ore-bearing bodies in Sanchakou copper deposit are diorite-granodiorite, biotite, silicitization, sericite, Qingiranlitization, etc. The Re-Os age of molybdenum is 416Ma 鹵6.4 Ma. and the LA-ICP-MS U-Pb age of zircon in diorite is 425 Ma 鹵3.9 Ma, which indicates that the deposit was formed in the Middle Silurian. W(Na_2O K _ 2O) of diorite-granodiorite in the ore area is 3.88 and 4.68 and the value of A- / NCK is all greater than 1, which is aluminum-saturated rock. The rock mass is low in potassium content (0.47 / 0.47 / 1.18) and in the Na / S / Na _ 2O _ 3 / 2.83 / 2.83 / 4.23T / w _ 2O _ 2) low 0.41 / 0.46 and 0.46 / 0.46, mostly in the low K _ 2O _ 3 series. The rock mass is rich in large ion lithophile elements, such as w(Ba)(260 脳 10 ~ (10) ~ (-6) ~ (4) 10 ~ (10) ~ (10) ~ (6) ~ (6), etc., and is characterized by high field and strong elements, such as w(Nb)(2.1 脳 10 ~ (10) -6 ~ (6) ~ (2. 6 脳 10 ~ (10) ~ (6) ~ (1) ~ (10) ~ (10) ~ (-6) ~ (1) ~ (11) 脳 10 ~ (10) ~ (1) ~ (1) ~ (1) ~ (1) ~ (1) ~ (1) ~ (1 脳 10 ~ (10) ~ (6) ~ (), and is characterized by the characteristics of the island arc magmatic rocks. The rock body is rich in K _ 2O / Na _ 2O _ (0.42), and has the characteristics of high wtiao _ 2o _ 3 (鈮，

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