本文選題：沂沭斷裂帶　切入點：中生代　出處：《地學前緣》2017年06期 　論文類型：期刊論文

【摘要】：以沂沭斷裂帶安丘地區(qū)中生代青山群火山巖為研究對象,在進行系統(tǒng)的元素-同位素分析的基礎(chǔ)上,探討其巖漿源區(qū)和巖石成因。安丘火山巖SiO2含量變化于56.5%~65.8%,主要為高鉀鈣堿性系列巖石,巖石組合為英安巖和粗面安山巖;安丘火山巖富集大離子親石元素和輕稀土元素,虧損高場強元素,顯示富集但變化范圍較大的Sr-Nd同位素組成((~(87)Sr/~(86)Sr)t=0.708 7~0.710 7,εNd(t)=-13.7~-5.93)。綜合分析表明,安丘火山巖為大陸下地殼物質(zhì)經(jīng)拆沉作用于地幔環(huán)境中發(fā)生部分熔融作用,與上地幔巖石發(fā)生交代作用后進入地表形成,且其源區(qū)中可能有軟流圈物質(zhì)的加入。
[Abstract]:The volcanic rocks of Mesozoic Qingshan group in Anqiu area of Yishu fault zone were studied. Based on systematic element-isotope analysis, the volcanic rocks of Qingshan Group in the Anqiu area of Yishu fault zone were studied. The SiO2 content of Anqiu volcanic rocks varies from 56.5 to 65.8, mainly composed of high-potassium calc-alkaline series rocks, the rock assemblages of dolomite and coarse-faced andesite, and the anqiu volcanic rocks are enriched in large ion lithophile elements and light rare earth elements. The loss of elements in high field strength indicates that the Sr-Nd isotopic composition, which is enriched but with a large range of variations, is 0.708 ~ (-87) ~ (-0.708) -0.710 ~ (7), 蔚 -Ndndltti-13.7 ~ (7) ~ (-5.93) ~ 3.The comprehensive analysis shows that the volcanic rocks of Anqiu occur partial melting in the mantle environment due to the delamination of continental lower crustal material. After metasomatism with the upper mantle rocks, it is formed on the surface, and there may be the addition of asthenospheric material in its source region.
【作者單位】： 中國地質(zhì)調(diào)查局天津地質(zhì)調(diào)查中心;中國地質(zhì)大學(武漢)地球科學學院;中國地質(zhì)調(diào)查局武漢地質(zhì)調(diào)查中心;
【基金】：國家自然科學基金委員會創(chuàng)新研究群體科學基金項目(40521001)
【分類號】：P588.14
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本文編號：1649367