發(fā)布時(shí)間：2018-03-15 12:42

  本文選題：閃石類礦物　切入點(diǎn)：退變質(zhì)榴輝巖　出處：《巖石礦物學(xué)雜志》2017年01期 　論文類型：期刊論文

【摘要】：勐庫(kù)地區(qū)新近發(fā)現(xiàn)的退變質(zhì)榴輝巖中晚期退變質(zhì)作用形成的閃石類礦物十分豐富,其攜帶了大量晚期退變質(zhì)過(guò)程中的巖石成因信息。本文通過(guò)系統(tǒng)的礦物學(xué)研究,鑒定出了3期10種閃石類礦物,其中以鎂鈣閃石、鎂角閃石、鐵鎂鈣閃石、鐵韭閃石、透閃石、陽(yáng)起石等鈣質(zhì)閃石類為主,有少量?jī)鏊{(lán)閃石、藍(lán)透閃石等鈉-鈣閃石類。研究發(fā)現(xiàn),隨著退變質(zhì)過(guò)程中時(shí)間的推移,角閃石的形成環(huán)境逐漸由還原環(huán)境向弱氧化環(huán)境、氧化環(huán)境演變。根據(jù)角閃石電子探針成分測(cè)試結(jié)果計(jì)算了相應(yīng)的溫度、壓力條件。結(jié)合巖相學(xué)的資料,將退變質(zhì)過(guò)程分為3期:(1)第1期早階段為近等溫降壓過(guò)程(p=0.56~0.75 GPa,t=642~709℃),主要形成鐵韭閃石、鐵鎂鈣閃石、鎂鈣閃石;晚階段為等溫降壓過(guò)程(p=0.39~0.56 GPa,t=619~642℃),主要形成鎂鈣閃石及少量鎂綠鈣閃石、鐵韭閃石;(2)第2期為降溫降壓過(guò)程(p=0.23~0.42 GPa,t=460~610℃),主要形成鎂角閃石、凍藍(lán)閃石及鐵角閃石;(3)第3期為近等溫降壓過(guò)程(p=0.09~0.31 GPa,t=350~420℃),主要形成透閃石、陽(yáng)起石、藍(lán)透閃石等。閃石類的成分變化反映了退變質(zhì)榴輝巖從地殼底部的角閃石榴輝巖-高壓麻粒巖相溫壓環(huán)境向中上地殼角閃巖相、綠片巖相溫壓環(huán)境的漸次退變質(zhì)作用過(guò)程。這與昌寧-孟連構(gòu)造帶上印支期的碰撞造山作用、燕山期的區(qū)域性地殼伸展、喜馬拉雅期的陸內(nèi)造山運(yùn)動(dòng)具有較好的對(duì)應(yīng)關(guān)系。
[Abstract]:The amphibole minerals formed by the late retrograde metamorphism of retrograde eclogite discovered recently in Mengku area are very rich and carry a large amount of petrogenetic information during the late retrograde metamorphism. In this paper, a systematic mineralogical study is carried out. Ten kinds of amphibole minerals were identified in three periods, among them, magnesium calcite, magnesium hornblende, ferric calcium amphibole, leek amphibole, tremolite, actinolite and other calcareous amphiboles, with a small amount of frozen blue amphibole, were identified. The study shows that with the time of retrograde metamorphism, the environment of hornblende formation gradually changes from reducing environment to weak oxidation environment. Evolution of the oxidation environment. The corresponding temperature and pressure conditions have been calculated based on the results of the amphibole electron probe composition test. Combined with petrographic data, The retrograde metamorphic process is divided into 3 stages: 1) the first stage is a near isothermal depressurization process, the first stage is a near isothermal depressurization process, the first stage is a near isothermal depressurization process, and the main formation of the retrograde metamorphic process is amphibole, ferromagnesium-calcium amphibole and magnesium-calcium amphibole. In the late stage, the isothermal depressurization process was 0.39 ~ 0.56 GPat ~ (619) ~ (642 鈩，

本文編號(hào)：1616077