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

【摘要】：安徽貴池地區(qū)是長江中下游成礦帶一個重要的成礦區(qū),分布一系列銅、金、鉬、多金屬礦床。這些礦床與區(qū)內(nèi)晚中生代花崗閃長斑巖體密切相關。雖然前人在成巖成礦方面取得了一定的成果,但這些花崗閃長斑巖成因及成礦仍存爭議。本論文針對上述問題,選擇貴池花崗閃長斑巖開展巖石學、礦物學、元素地球化學、鋯石U-Pb年代學、鋯石Hf同位素以及單礦物原位地球化學研究,結合前人的研究成果,獲得如下認識。1.礦物地球化學研究表明貴池花崗閃長斑巖可能是殼�；旌系漠a(chǎn)物,而地殼成分占主要地位;巖漿的結晶溫度在600℃~800℃。2.貴池花崗閃長斑巖(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Mg#值,富集Rb、K,相對虧損Ba、Sr,輕稀土富集,重稀土虧損,有弱Eu負異常等這些特征說明幔源巖漿和殼源巖漿的混合可能是貴池花崗閃長斑巖形成的主要機制,而新元古代變質(zhì)基底物質(zhì)是其主要來源,巖漿演化過程中經(jīng)歷了明顯的斜長石、鉀長石和副礦物等結晶分異作用。其可能與古太平洋板塊俯沖密切相關。3.高質(zhì)量鋯石U-Pb年齡結果表明貴池花崗閃長斑巖體為晚侏羅世,是長江中下游成礦帶第一期巖漿活動的產(chǎn)物。4.鋯石原位地球化學、Lu-Hf同位素特征(ε_(Hf)(t)=-12.7~-3.0,t_(DM2)=1.4~2.0Ga,以及磷灰石稀土元素特征進一步支持貴池花崗閃長斑巖為殼幔混合產(chǎn)物,而中元古—古元古代下地殼物質(zhì)占主導地位。5.本區(qū)Cu、Mo、Au成礦作用與巖漿的高氧逸度密切相關。
[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：1794608