本文選題：花崗閃長(zhǎng)斑巖 + 鋯石��； 參考：《合肥工業(yè)大學(xué)》2017年碩士論文

【摘要】：安徽貴池地區(qū)是長(zhǎng)江中下游成礦帶一個(gè)重要的成礦區(qū),分布一系列銅、金、鉬、多金屬礦床。這些礦床與區(qū)內(nèi)晚中生代花崗閃長(zhǎng)斑巖體密切相關(guān)。雖然前人在成巖成礦方面取得了一定的成果,但這些花崗閃長(zhǎng)斑巖成因及成礦仍存爭(zhēng)議。本論文針對(duì)上述問(wèn)題,選擇貴池花崗閃長(zhǎng)斑巖開(kāi)展巖石學(xué)、礦物學(xué)、元素地球化學(xué)、鋯石U-Pb年代學(xué)、鋯石Hf同位素以及單礦物原位地球化學(xué)研究,結(jié)合前人的研究成果,獲得如下認(rèn)識(shí)。1.礦物地球化學(xué)研究表明貴池花崗閃長(zhǎng)斑巖可能是殼�；旌系漠a(chǎn)物,而地殼成分占主要地位;巖漿的結(jié)晶溫度在600℃~800℃。2.貴池花崗閃長(zhǎng)斑巖(SiO_2=63.3%~64.8%)為高鉀鈣堿性Ⅰ型花崗巖,具有較低Cr(30×10~(-6)~50×10~(-6))含量,低Nb/U(3.40~7.23)和Nb/Ta比值(11.6~13.5),較高M(jìn)g#值,富集Rb、K,相對(duì)虧損Ba、Sr,輕稀土富集,重稀土虧損,有弱Eu負(fù)異常等這些特征說(shuō)明幔源巖漿和殼源巖漿的混合可能是貴池花崗閃長(zhǎng)斑巖形成的主要機(jī)制,而新元古代變質(zhì)基底物質(zhì)是其主要來(lái)源,巖漿演化過(guò)程中經(jīng)歷了明顯的斜長(zhǎng)石、鉀長(zhǎng)石和副礦物等結(jié)晶分異作用。其可能與古太平洋板塊俯沖密切相關(guān)。3.高質(zhì)量鋯石U-Pb年齡結(jié)果表明貴池花崗閃長(zhǎng)斑巖體為晚侏羅世,是長(zhǎng)江中下游成礦帶第一期巖漿活動(dòng)的產(chǎn)物。4.鋯石原位地球化學(xué)、Lu-Hf同位素特征(ε_(tái)(Hf)(t)=-12.7~-3.0,t_(DM2)=1.4~2.0Ga,以及磷灰石稀土元素特征進(jìn)一步支持貴池花崗閃長(zhǎng)斑巖為殼�；旌袭a(chǎn)物,而中元古—古元古代下地殼物質(zhì)占主導(dǎo)地位。5.本區(qū)Cu、Mo、Au成礦作用與巖漿的高氧逸度密切相關(guān)。
[Abstract]:The Guichi area, Anhui Province, is an important metallogenic area in the middle and lower reaches of the Yangtze River, with a series of copper, gold, molybdenum and polymetallic deposits distributed. These deposits are closely related to the late Mesozoic granodiorite in the area. Although some achievements have been made in diagenesis and mineralization, the genesis and mineralization of these granodiorite porphyry are still controversial. In this paper, we select granodiorite porphyry in Guichi to study petrology, mineralogy, element geochemistry, zircon U-Pb chronology, zircon HF isotope and in situ geochemistry of single mineral. Gain the following knowledge. Mineral geochemistry shows that granodiorite porphyry may be the product of crust-mantle mixing, and the crustal composition is dominant, and the crystallization temperature of magma is at 600 鈩，

本文編號(hào)：1794608