本文關(guān)鍵詞： 南木林盆地 拉薩地塊 花崗斑巖 高鍶低釔斑巖 中新世 伸展背景　出處：《地質(zhì)論評》2017年03期 　論文類型：期刊論文

【摘要】：拉薩地塊南木林盆地北緣的林子宗群火山巖地層侵位有大量的花崗斑巖巖株和巖脈,空間分布上與南北向正斷層的次級斷裂相一致。本次研究對南木林盆地北緣的花崗斑巖進行了系統(tǒng)的元素地球化學(xué),LA-MCICP-MS鋯石U-Pb年代學(xué)和Lu-Hf同位素測試。數(shù)據(jù)結(jié)果表明:花崗斑巖具有高硅(68.31%~71.34%)、高鉀(4.52%~4.96%)、高(La/Yb)N(21.59~36.81)、Sr/Y(Sr/Y=15.59~38.10)等特征,富集大離子親石元素(LILE),虧損高場強元素(HFSE);花崗斑巖LA-MC-ICP-MS鋯石U-Pb年齡為12.2±0.1Ma,ε_(Hf)(t)值為-0.6~+4.0。拉薩地塊南木林盆地北緣花崗斑巖巖石學(xué)、地球化學(xué)特征顯示其為新生下地殼部分熔融產(chǎn)物,且源區(qū)殘留了石榴子石、金紅石、角閃石,無斜長石殘留,在巖漿上侵過程中,發(fā)生了堿性長石的分離結(jié)晶作用。花崗斑巖侵位于中新世,與區(qū)內(nèi)南北向裂谷發(fā)育時代一致,成分上類似于拉薩地塊南部同時期發(fā)育的高鍶低釔斑巖、鉀質(zhì)巖,同為印度—歐亞大陸碰撞后東西向伸展背景產(chǎn)物。
[Abstract]:There are a large number of granitic porphyry plants and veins in the volcanic strata of the Linzizong Group in the northern margin of the South Mulin Basin in Lhasa block. The spatial distribution is consistent with the secondary faults of the normal fault in the south and north direction. The element geochemistry of the granitic porphyry in the northern margin of the southern Mulin basin has been systematically studied in this study. LA-MCICP-MS zircon U-Pb geochronology and Lu-Hf isotopic measurements. The data show that the granitic porphyry has a high silicon content of 68.31 and 71.34. High potassium 4.52 / 4.96, high La / Yb / N21.59N / 36.81 / S / S / Y / S / Y 15.59 / 38.10). The large ion lithophile element Lilei is enriched, and the high field strength element is depleted. The LA-MC-ICP-MS zircon U-Pb age of granitic porphyry is 12.2 鹵0.1 Ma. The 蔚 -0.6-4.0. the petrology of granitic porphyry in the northern margin of the southern Mulin basin in Lhasa block shows that the porphyry is a partial melting product of the lower crust. And the garnet, rutile, amphibole and no plagioclase remained in the source area. During the magmatic transgression, the alkaline feldspar was separated and crystallized. The granitic porphyry transgression occurred in the Miocene. The composition is similar to that of high strontium and low yttrium porphyry and kalitic rock developed in the southern Lhasa block during the same period and is the product of east-west extension after the collision between India and Eurasia.
【作者單位】： 中國地質(zhì)科學(xué)院礦產(chǎn)資源研究所國土資源部成礦作用與資源評價重點實驗室;成都理工大學(xué)地球科學(xué)學(xué)院;
【基金】：地調(diào)項目(編號:12120114068401) 公益性行業(yè)專項(編號:201511022-02)的成果~~
【分類號】：P588.1;P597.3
【正文快照】： 自從印度、歐亞板塊在45~65Ma碰撞以來(莫殼板片部分熔融(Qu Xiaoming et al.,2004)、交代宣學(xué)等,2003;莫宣學(xué),2011),碰撞后巖漿活動廣泛地幔楔部分熔融(Gao Yongfei et al.,2007)等幾種分布于青藏高原之上,包括鉀質(zhì)—超鉀質(zhì)火山巖、高觀點。本人在南木林盆地北緣,申扎—定結(jié)

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