浙江浮蓋山花崗巖巖石成因與地貌演化
發(fā)布時(shí)間：2018-10-24 15:20
【摘要】：浮蓋山花崗巖體位于浙江西南部,武夷山北緣,本文在野外調(diào)查的基礎(chǔ)上,通過鏡下薄片鑒定、鋯石LA-ICP-MS U-Pb測年、巖石主微量元素分析、電子探針分析等方面的研究,厘定了研究區(qū)內(nèi)花崗巖的成巖時(shí)限,討論了花崗巖巖石成因、成巖有關(guān)的構(gòu)造環(huán)境,并且對浮蓋山地區(qū)的地貌特征分別從宏觀、中觀和微觀三個(gè)角度進(jìn)行了分析,闡述了該區(qū)的地貌演化過程。本文不僅為浮蓋山國家地質(zhì)公園增加了科學(xué)研究內(nèi)容,并且為東南沿海一帶的浙閩花崗巖的研究增加了新的素材。該區(qū)花崗巖主要為黑云母二長花崗巖,將分選磨碎的樣品挑選鋯石,并利用LA-ICP-MS U-Pb測年技術(shù)進(jìn)行單顆粒鋯石微區(qū)測年,顯示年齡為103.3±2.7Ma,為早白堊世晚期。巖石地球化學(xué)特征顯示,花崗巖體富硅,高堿,低磷,富集Rb、Th、U,虧損Ba、Sr、Ti、P等元素,輕稀土略多于重稀土,Eu負(fù)異常明顯,鋯石飽和溫度為761-791℃;單礦物地球化學(xué)特征上,黑云母富鐵貧鎂,斜長石多屬鈉長石至更長石,體現(xiàn)鈉質(zhì)交代作用,屬于高分異I型花崗巖體,具有高鉀鈣堿性及后碰撞花崗巖特征。浮蓋山花崗巖與同時(shí)代的閩浙花崗巖A型、I型花崗巖構(gòu)造環(huán)境相似,與太平洋板塊碰撞華南板塊后引發(fā)的伸展運(yùn)動(dòng)有關(guān)。浮蓋山花崗巖景觀地貌具有一定的特殊性,石蛋分布廣泛。浮蓋山地區(qū)在中新世中期前地殼穩(wěn)定,經(jīng)風(fēng)化剝蝕后抬升,至上新世中期再次形成穩(wěn)定地殼,上新世晚期開始,地殼再次強(qiáng)烈抬升�；◢弾r體在出露地表后,在發(fā)育大量節(jié)理、遭受強(qiáng)烈風(fēng)化及發(fā)育晶洞構(gòu)造的情況多種機(jī)制共同作用下,導(dǎo)致現(xiàn)在地貌的形成
[Abstract]:The Fugaishan granite body is located in the southwest of Zhejiang Province and the northern margin of Wuyi Mountain. Based on the field investigation, this paper studies on the basis of the field investigation, the identification of thin slices under microscope, the LA-ICP-MS U-Pb dating of zircon, the analysis of main trace elements of rocks, the electron probe analysis, etc. The diagenesis time of granites in the study area is determined, the genesis of granite rocks and diagenetic tectonic environment are discussed, and the geomorphological characteristics of the Fupaishan area are analyzed from three angles: macroscopic, mesoscopic and microscopic, respectively. The evolution process of geomorphology in this area is expounded. This paper not only adds scientific research contents for Fugaishan National Geopark, but also adds new materials for the study of Zhejiang and Fujian granite along the southeast coast. The granites in this area are mainly biotite monomorphic granites. Zircons are selected from ground samples, and single grain zircon microzone dating is performed by LA-ICP-MS U-Pb dating technique. The age is 103.3 鹵2.7 Ma, which is late early Cretaceous. The petrogeochemical characteristics of the granite show that the granite is rich in silicon, high alkali, low phosphorus, enriched in Rb,Th,U, depleted elements such as Ba,Sr,Ti,P, slightly more light rare earth than heavy rare earth, Eu negative anomaly is obvious, zircon saturation temperature is 761-791 鈩，
本文編號：2291748
[Abstract]:The Fugaishan granite body is located in the southwest of Zhejiang Province and the northern margin of Wuyi Mountain. Based on the field investigation, this paper studies on the basis of the field investigation, the identification of thin slices under microscope, the LA-ICP-MS U-Pb dating of zircon, the analysis of main trace elements of rocks, the electron probe analysis, etc. The diagenesis time of granites in the study area is determined, the genesis of granite rocks and diagenetic tectonic environment are discussed, and the geomorphological characteristics of the Fupaishan area are analyzed from three angles: macroscopic, mesoscopic and microscopic, respectively. The evolution process of geomorphology in this area is expounded. This paper not only adds scientific research contents for Fugaishan National Geopark, but also adds new materials for the study of Zhejiang and Fujian granite along the southeast coast. The granites in this area are mainly biotite monomorphic granites. Zircons are selected from ground samples, and single grain zircon microzone dating is performed by LA-ICP-MS U-Pb dating technique. The age is 103.3 鹵2.7 Ma, which is late early Cretaceous. The petrogeochemical characteristics of the granite show that the granite is rich in silicon, high alkali, low phosphorus, enriched in Rb,Th,U, depleted elements such as Ba,Sr,Ti,P, slightly more light rare earth than heavy rare earth, Eu negative anomaly is obvious, zircon saturation temperature is 761-791 鈩，
本文編號：2291748
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