本文選題：花崗巖　切入點(diǎn)：華北克拉通　出處：《成都理工大學(xué)》2015年碩士論文

【摘要】：本研究以冀北康保晚古生代花崗巖類(lèi)為研究對(duì)象,識(shí)別出了8個(gè)具有不同類(lèi)型花崗巖的巖體,并且進(jìn)行了野外的地質(zhì)觀察、室內(nèi)的鏡下鑒定、電子探針測(cè)試以及鋯石U-Pb定年等方面的細(xì)致工作,取得了以下認(rèn)識(shí):(1)不同巖體的花崗巖礦物含量差別較大,西五福堂巖體、新村巖體、李生寶溝巖體、三老虎巖體和前孟家地巖體,花崗巖中暗色礦物依次逐漸減少,粒度由細(xì)粒到粗粒,巖石類(lèi)型由花崗閃長(zhǎng)巖-二長(zhǎng)花崗巖-正長(zhǎng)花崗巖。小西溝巖體、石柱梁巖體、大盤(pán)溝巖體,花崗巖中斜長(zhǎng)石均較少,堿性長(zhǎng)石含量依次逐漸增加,由正長(zhǎng)花崗巖到堿長(zhǎng)花崗巖,結(jié)構(gòu)由斑狀-含斑-似斑狀變化。礦物電子探針測(cè)試數(shù)據(jù)可以得西五福堂巖體的中細(xì)粒含角閃黑云花崗閃長(zhǎng)巖中,斜長(zhǎng)石(An=39.6~43.4)應(yīng)屬于中長(zhǎng)石;新村巖體的中粒含角閃黑云二長(zhǎng)花崗巖的斜長(zhǎng)石中,斜長(zhǎng)石(An=25.1~28.9)為更長(zhǎng)石;李生寶溝巖體的中細(xì)粒二長(zhǎng)花崗巖中的斜長(zhǎng)石的特征相似,斜長(zhǎng)石牌號(hào)應(yīng)均為更長(zhǎng)石-鈉長(zhǎng)石(An=2.9~16.8)。石柱梁和大盤(pán)溝巖體的花崗巖所含的斜長(zhǎng)石為鈉長(zhǎng)石(An=0~1.6)。西五福堂巖體花崗巖中黑云母為鎂鐵質(zhì)黑云母,顯示出殼�；烊镜膩�(lái)源和造山帶花崗巖中黑云母的特征。其他巖體花崗巖均為鐵質(zhì)及富鐵黑云母,物質(zhì)來(lái)源于地殼,為堿性花崗巖中黑云母的特征。角閃石屬于鈣角閃石((Ca+Na)B≥1.00,NaB0.50)。進(jìn)一步分別是淺閃石、鎂綠鈣閃石和綠鈣閃石,也顯示出了幔源物質(zhì)混染的特征。(2)花崗巖中鋯石Ti溫度計(jì)測(cè)算結(jié)果表明,康保晚古生代花崗質(zhì)巖漿的形成、結(jié)晶的平均溫度均大于750℃,這些花崗巖和花崗閃長(zhǎng)巖均起源于地殼下部。鋯石Ti溫度與Zr/Hf、Th/U的相關(guān)性分析認(rèn)為,巖漿冷凝時(shí)整個(gè)巖漿系統(tǒng)處于開(kāi)放的系統(tǒng)下,而后期多期的流體或者巖漿以富U、Hf為特點(diǎn)(3)石柱梁巖體花崗巖LA-ICP-MS鋯石U-Pb年齡為260.6±1.6Ma、小西溝巖體花崗巖LA-ICP-MS鋯石U-Pb年齡為264.1±1.7Ma、前孟家地巖體花崗巖LA-ICP-MS鋯石U-Pb年齡為269.5±2.7Ma、三老虎巖體花崗巖LA-ICP-MS鋯石U-Pb年齡為276.3±1.9Ma、新村巖體花崗巖LA-ICP-MS鋯石U-Pb年齡為280.4±2.0Ma、西五福堂巖體花崗巖LA-ICP-MS鋯石U-Pb年齡為284.7±1.7Ma。西五福堂巖體的中細(xì)粒含角閃黑云花崗閃長(zhǎng)巖和新村巖體的中粒含角閃黑云二長(zhǎng)花崗巖形成于大陸邊緣弧環(huán)境向同碰撞轉(zhuǎn)換階段,其他巖石巖體的花崗巖巖性上為二長(zhǎng)花崗巖和偏堿性花崗巖,應(yīng)是同碰撞后期到后碰撞環(huán)境下形成的。
[Abstract]:In this study, eight granites with different types of granites were identified from the late Paleozoic granites in Kangbao, northern Hebei Province, and field geological observations were carried out.The detailed work of electron probe test and zircon U-Pb dating has obtained the following understanding: the content of granite minerals in different rock masses is quite different, the West Wufutang, Xincun, Li Shengbaogou, etc.The dark minerals in the granites are gradually reduced from granulite to coarse-grained, and the rock types are from granodiorite to monzogranite to syenite.There are less plagioclase in Xiaoxigou rock body, Shizhouliang rock body, Dapanggou rock mass and granite, and the content of alkaline feldspar increases gradually, from syenite to alkali feldspar granite, and the structure changes from porphyry, porphyry to porphyry.From the mineral electron probe data, it can be concluded that the plagioclase of the medium and fine grained amphibole granodiorite of the West Wufutang rock body, the plagioclase of the plagioclase Anjiao 39.6n43.4) should belong to the plagioclase containing hornblende monzogranite in the Xincun rock mass.The plagioclase contained in the granite of Shizhulliang and Dapangou is albite.The biotite in the granites of the West Wufutang granite is magnesia-iron biotite, which shows the origin of crust and mantle mixing and the characteristics of biotite in the granites of the orogenic belt.The other granites are ferric and iron-rich biotite, derived from the crust and characterized by biotite in alkaline granites.Hornblende belongs to calcium hornblende (Ca Na)B 鈮，

本文編號(hào)：1715248