CAJ | 학술논문

花岗岩浆液态不混溶作用和饱和 H2 O 花岗岩浆的热液出溶作用是花岗岩类矿床成矿流体形成的重要机制。利用最新式热液金刚石压腔，开展了成矿流体形成机制的原位观测实验。在岩浆热液出溶过程的实验中，初始样品为各类硅酸盐和纯 H2 O 或 LiCl 水溶液，在 H2 O 饱和状态中，硅酸盐熔体珠不断分异出富 H2 O 的流体。花岗岩浆液态不混溶实验的初始样品为 NaAlSi3 O8 LiAlSiO4 SiO2 LiCl H2 O。在硅酸盐完全重熔后的降温过程中，硅酸盐熔体珠分离出富 H2 O 熔体相和贫 H2 O 熔体相，压力的突然降低促进了相分离的发生。研究表明：岩浆热液的出溶作用发生在 H2 O 饱和的条件下，是岩浆的“第二次”沸腾作用，对花岗岩型稀有金属矿床的形成具有重要意义；花岗岩浆液态不混溶产生的富 H2 O 熔体易于结晶出粗大晶体，暗示岩浆液态不混溶作用可能是一些花岗伟晶岩形成的主要机制。两类成矿流体形成机制实验条件的差异表明，Li 是花岗岩浆发生不混溶作用的重要因素。在今后的研究中，应把热液金刚石压腔的原位观测与微束分析技术结合，在高温高压状态下分析成矿元素的迁移和富集规律。
화강암장액태불혼용작용화포화 H2 O 화강암장적열액출용작용시화강암류광상성광류체형성적중요궤제。이용최신식열액금강석압강，개전료성광류체형성궤제적원위관측실험。재암장열액출용과정적실험중，초시양품위각류규산염화순 H2 O 혹 LiCl 수용액，재 H2 O 포화상태중，규산염용체주불단분이출부 H2 O 적류체。화강암장액태불혼용실험적초시양품위 NaAlSi3 O8 LiAlSiO4 SiO2 LiCl H2 O。재규산염완전중용후적강온과정중，규산염용체주분리출부 H2 O 용체상화빈 H2 O 용체상，압력적돌연강저촉진료상분리적발생。연구표명：암장열액적출용작용발생재 H2 O 포화적조건하，시암장적“제이차”비등작용，대화강암형희유금속광상적형성구유중요의의；화강암장액태불혼용산생적부 H2 O 용체역우결정출조대정체，암시암장액태불혼용작용가능시일사화강위정암형성적주요궤제。량류성광류체형성궤제실험조건적차이표명，Li 시화강암장발생불혼용작용적중요인소。재금후적연구중，응파열액금강석압강적원위관측여미속분석기술결합，재고온고압상태하분석성광원소적천이화부집규률。
The liquid immiscibility and hydrothermal fluid exsolution from magma are the important separation mechanisms of ore-forming fluid from granite magma.At present,the understanding of the two mechanisms is mainly from researches of melt and fluid inclusions,or none-in-situ experiments.The newest hydrothermal diamond anvil-cell (HDAC)is used to observe the two processes in situ.In exsolution experiments with the initial sample of silicate and pure H2 O or LiCl dissolved aqueous fluid, the H2 O-rich fluid separated from H2 O-saturated silicate melt when H2 O is saturated in silicate melt.In the experiment of liquid immiscibility with the initial samples of NaAlSi3 O8-LiAlSiO4-SiO2-LiCl-H 2 O, the silicate melt balls can be separated into a H2 O-rich melt and H2 O-poor melt during cooling from homogeneous silicate melt. The sharp fall of pressure can induce the liquid immiscibility. These experimental results show that the hydrothermal fluid exsolution occurred in H2 O-saturated silicate melt is the second boiling of magma,and plays a great role in the mineralization of granite type deposit.The H2 O-rich melt separated from granite magma by liquid immiscibility can crystallize big and oriented crystals,suggesting that liquid immiscibility of granite magma is an important formation mechanism for granite pegmatite.The differences between the above two type experiments suggest that the element Lithium is an important factor for liquid immiscibility in granite magma.In the further research,we should combine the HDAC with microbeam analysis in order to analyze the enrichment process of metal element at high temperature and pressure.