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赤门角闪辉长岩是中国东南部晚白垩世末基性岩浆活动的产物,分布在福建省南平市的北部,总体呈近NS向展布。岩石属于低钾(拉斑)岩石系列,富A l、Na2O>K2O的特征,岩浆演化过程中经历了以橄榄石、辉石、斜长石和Ti-Fe氧化物的分离结晶作用。赤门角闪辉长岩具相对富集大离子亲石元素(LILE)和轻稀土元素(LREE)、亏损高场强元素(HFSE)的特性,不相容元素蛛网图显示出消减带岩石的地球化学性质,以Nb、Ta、Ti负异常为特征。微量元素地球化学研究表明,赤门角闪辉长岩浆在上升侵位过程中未发生地壳物质混染,来自不含石榴石的富集岩石圈地幔岩部分熔融的产物,地幔源区的演化与太平洋板块俯冲密切相关。赤门角闪辉长岩形成于大陆拉张带-陆内初始裂谷的过渡环境。综合晚中生代的基性岩类资料,与形成较早的沿海辉长岩对比研究,赤门角闪辉长岩是拉张向裂谷转换体制下形成的过渡岩石类型,标志初始裂谷活动的开始。
The Chek Menghua flash gabbro is a product of the Late Late Cretaceous mafic magmatism in the southeastern part of China, and is distributed in the northern part of Nanping City, Fujian Province. The rocks belong to the series of low-potassium (tabby) rocks rich in Al, Na2O> K2O. During the evolution of magma, they undergo the crystallization of olivine, pyroxene, plagioclase and Ti-Fe oxide. The Chek Menghua glare gabbro is relatively enriched in LILE and LREE and depleted in high field strength elements (HFSE). Incompatible elemental cobweb maps show the depletion of rock-bearing Geochemical properties, with Nb, Ta, Ti negative anomalies are characterized. Trace element geochemical studies show that there is no crustal contamination during the upwelling process in the Chek Menjiao Glacier magmatism, partial melting of enriched lithospheric mantle rock without garnet, evolution of the mantle source region and Pacific plate subduction is closely related. The Chek Menghua flash gabbro formed in the transition zone between the continental pull zone and the inland initial rift. Based on the comparison of the Late Mesozoic basic rock data with that of the earlier formation of coastal gabbro, the Cheonmenjiao flash gabbro is a type of transitional rock formed under the tension-rift transition system and marks the initial rifting activity Start.