浙江浮盖山花岗岩岩石成因与地貌演化
发布时间：2018-10-24 15:20
【摘要】：浮盖山花岗岩体位于浙江西南部,武夷山北缘,本文在野外调查的基础上,通过镜下薄片鉴定、锆石LA-ICP-MS U-Pb测年、岩石主微量元素分析、电子探针分析等方面的研究,厘定了研究区内花岗岩的成岩时限,讨论了花岗岩岩石成因、成岩有关的构造环境,并且对浮盖山地区的地貌特征分别从宏观、中观和微观三个角度进行了分析,阐述了该区的地貌演化过程。本文不仅为浮盖山国家地质公园增加了科学研究内容,并且为东南沿海一带的浙闽花岗岩的研究增加了新的素材。该区花岗岩主要为黑云母二长花岗岩,将分选磨碎的样品挑选锆石,并利用LA-ICP-MS U-Pb测年技术进行单颗粒锆石微区测年,显示年龄为103.3±2.7Ma,为早白垩世晚期。岩石地球化学特征显示,花岗岩体富硅,高碱,低磷,富集Rb、Th、U,亏损Ba、Sr、Ti、P等元素,轻稀土略多于重稀土,Eu负异常明显,锆石饱和温度为761-791℃;单矿物地球化学特征上,黑云母富铁贫镁,斜长石多属钠长石至更长石,体现钠质交代作用,属于高分异I型花岗岩体,具有高钾钙碱性及后碰撞花岗岩特征。浮盖山花岗岩与同时代的闽浙花岗岩A型、I型花岗岩构造环境相似,与太平洋板块碰撞华南板块后引发的伸展运动有关。浮盖山花岗岩景观地貌具有一定的特殊性,石蛋分布广泛。浮盖山地区在中新世中期前地壳稳定,经风化剥蚀后抬升,至上新世中期再次形成稳定地壳,上新世晚期开始,地壳再次强烈抬升。花岗岩体在出露地表后,在发育大量节理、遭受强烈风化及发育晶洞构造的情况多种机制共同作用下,导致现在地貌的形成
[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 卤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，
本文编号：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 卤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，
本文编号：2291748
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