本文選題：地球化學(xué) + 鋯石U-Pb年代學(xué)　； 參考：《中國(guó)地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：河南嵩縣牛頭溝礦田中發(fā)育多條花崗巖脈,巖性包括花崗斑巖和斑狀二長(zhǎng)花崗巖。為查明礦田中花崗巖的形成年代、機(jī)制和構(gòu)造背景,本次工作系統(tǒng)采集了松里溝、沙土洼和下莊花崗斑巖,以及沙土洼和木耳溝斑狀二長(zhǎng)花崗巖,并進(jìn)行了巖相學(xué)、地球化學(xué)、年代學(xué)和Hf同位素組成研究,取得如下成果和認(rèn)識(shí):(1)松里溝和下莊花崗斑巖為鈣堿性、高鉀巖石,沙土洼花崗斑巖和斑狀二長(zhǎng)花崗巖為堿性、鉀玄巖系列巖石。該區(qū)花崗巖均富集大離子親石元素Rb、K、虧損高場(chǎng)強(qiáng)元素Nb、Ta、Ti、P,還主要表現(xiàn)出負(fù)Eu異常的特點(diǎn),其中的花崗斑巖虧損中稀土,而斑狀二長(zhǎng)花崗巖虧損重稀土。(2)松里溝、沙土洼花崗斑巖和沙土洼、木耳溝斑狀二長(zhǎng)花崗巖形成于168.8±4.1Ma、162.6±5.7Ma和166.8±1.6Ma、163.1±2.3Ma。結(jié)合前人研究,限定牛頭溝礦田花崗質(zhì)巖漿的活動(dòng)時(shí)限為160~169Ma。(3)松里溝、沙土洼、下莊花崗斑巖和沙土洼、木耳溝斑狀二長(zhǎng)花崗巖的εHf(t)為-24.43~-19.79、-24.10~-20.92、-24.18~-20.17和-22.96~-15.84、-21.35~-16.04;TDM2為2434~2718Ma、2511~2706Ma、2473~2720Ma和2190~3140Ma、2198~2566Ma。它們是古老地殼物質(zhì)太華群部分熔融的產(chǎn)物,為I型花崗巖。(4)沙土洼和木耳溝斑狀二長(zhǎng)花崗巖主要是角閃巖和斜長(zhǎng)角閃巖在800~850℃、1.4~1.7GPa下部分熔融的產(chǎn)物,巖漿源區(qū)的殘留相礦物可能為石榴子石、金紅石、鈦鐵礦,少量單斜輝石、角閃石和斜長(zhǎng)石。松里溝和下莊花崗斑巖的原巖是黑云斜長(zhǎng)片麻巖、TTG片麻巖中的偏酸性部分和鉀長(zhǎng)花崗片麻巖,沙土洼花崗斑巖的原巖主要是角閃巖和斜長(zhǎng)角閃巖,它們是在707~728℃、687~743℃、718~737℃和較低壓力條件下部分熔融形成,巖漿源區(qū)的殘留相礦物可能為斜長(zhǎng)石、角閃石和磷灰石。(5)牛頭溝礦田花崗巖的形成與古太平洋板塊西向俯沖、巖石圈伸展、軟流圈上涌有關(guān)。
[Abstract]:There are many granite veins in Niutougou ore field, Songxian, Henan Province. The lithology includes granitic porphyry and porphyry monzogranite. In order to find out the age, mechanism and tectonic setting of granites in the ore field, Songligou, Shatuwa and Xiazhuang granitic porphyry, as well as sandy and muergou porphyry granites, were collected in this work system, and the lithofacies and geochemistry were carried out. The results of geochronology and HF isotopic composition are as follows: (1) the Songligou and Xiazhuang granitic porphyry rocks are calc-alkaline, high-potassium rocks, shatuwa granitic porphyry rocks and porphyry granitic granites are alkaline, and kaliacite series rocks. The granites are rich in large ion lithophile elements RbLi K and depleted in high field strength element Nbtadao TiTiP.It also shows the characteristics of negative EU anomaly, in which granitic porphyry depleted rare earths, while porphyry granites depleted heavy rare earths. (2) Songligou, In Shatuwa granitic porphyry and Shatuwa, Muergou porphyry monzonitic granites were formed at 162.6 鹵5.7 Ma and 163.1 鹵2.3 Ma at 168.8 鹵4.1 Ma and 166.8 鹵1.6 Ma, respectively. In combination with previous studies, the time limit of granitic magma activity in the Niutougou Orefield is 160- 169Ma. (3) Songligou, Shatuwa, Xiazhuang granitic porphyry and sandy soil depression, the 蔚 HF (t) of the porphyry monzogranites in Muergou are -24.43U -19.79U -24.10-20.92- 24.18CU -20.17 and -22.96- 15.84W -15.84W -21.356Ma TDM2: 24342718Ma 25112706Ma 2511732720Ma and 2190NU 3140MaA 1982D 2566Ma. They are the product of partial melting of the ancient crustal material Taihua Group and belong to I-type granite. (4) the Shatuwa and Muergou porphyry monzomorphic granites are mainly the product of partial melting of amphibolite and amphibolite under 800 ~ 850 鈩，

本文編號(hào)：2088715