东昆仑拉陵灶火矿区花岗闪长岩Sr-Nd-Pb同位素特征及其地质意义  

Sr-Nd-Pb ISOTOPIC CHARACTERISTICS OF ORE-BEARING GRANODIORITES FROM LALINGZAOHUO DEPOSIT AND ITS GEOLOGICAL SIGNIFICANCE

作　　者：李玉春 李彬 陈静[3] 张启梅[3] 

机构地区：[1]青海省第五地质矿产勘查院,青海西宁810000 [2]青海省电力设计院地质勘测室,青海西宁810008 [3]青海省地质调查院,青藏高原北部地质过程与矿产资源重点实验室,青海西宁810012

出　　处：《矿物岩石》2013年第3期110-115,共6页Mineralogy and Petrology

基　　金：国土资源部公益性行业科研专项(201211037);青海省自然科学基金项目(2012-Z-934Q)

摘　　要：拉陵灶火钼多金属矿床是东昆仑成矿带内新发现的矽卡岩型-斑岩型Mo-Cu(Au)矿床。针对该矿区中与成矿密切的花岗闪长岩进行的Sr-Nd-Pb同位素研究,结果表明:岩石的初始87Sr/86Sr比值为0.711 059～0.714 079,143 Nd/144 Nd的初始计算值为0.511 951～0.512 005,εNd(t)值为-7.4～-6.3;经校正后的206Pb/204Pb(i)变化范围为18.711～18.990、207Pb/204Pb(i)为15.656～15.671、208Pb/204Pb(i)为38.742～39.132,μ值介于9.52～9.57。结合Sr-Nd-Pb同位素特征、岩石地球化学以及其他资料表明被俯冲板片流体所交代的富集地幔可能为岩浆的源区。含矿岩体的形成应与俯冲结束与碰撞开始时的板片断离作用有关。Newly discovered Lalingzaohuo molybdenum polymetallic deposit is a skarn-type-por- phyry Mo-Cu （Au） deposit occurred in the East Kunlun metallogenic belt. Sr-Nd-Pb isotopic studies are carried out for the granodiorite that closely associated with mineralization. It shows that. the initial 87 Sr/86 Sr ratio ranges from 0. 711 059 to 0. 714 079, initial calculated 143 Nd/144 Nd value ranges from 0. 511 951 to 0. 512 005,the value of εNd （t） ranges from -7.4 to --6.3;cor- rected 206Pb/204Pb（i） ranges from 18. 711 to 18. 990,207Pb/204Pb（i） ranges from 15. 656 to 15. 671, 208Pb/204Pb（i）. /range from 38. 742 to 39. 132,the μ value ranges from 9.52 to 9.57. Sr-Nd-Pb i- sotopic characteristics, geochemistry and other information indicate that the magma source region may he enriched mantle with metasomatic process hy fluid from suhducted slab. The formation of ore-bearing granites should be related to the slab break-off at the end of the subduction and the beginning of the collision stage.

关 键 词：花岗闪长岩 Sr-Nd—Pb同位素 富集地幔 拉陵灶火地区 

分 类 号：P588.122[天文地球—岩石学] P597.2[天文地球—地质学]