Early Silurian mafic–ultramafic and granitic plutonism in contemporaneous flysch, Magerøy, northern Norway: U–Pb ages and regional significance
Early Silurian mafic–ultramafic and granitic plutonism in contemporaneous flysch, Magerøy, northern Norway: U–Pb ages and regional significance
复制标题
挪威北部马格罗伊同期复理石中的早期志留世镁铁质-超镁铁质和花岗岩深成作用：U-Pb年龄和区域意义
DOI：
--
复制
发表时间：
2006
影响因子：
2.7
通讯作者：
R. J. Roberts
中科院分区：
文献类型：
--
作者：
F. Corfu;T. Torsvik;T. Torsvik;T. Andersen;L. Ashwal;D. M. Ramsay;R. J. Roberts
加里东Magerøy序列包括最早的志留纪碎屑变质沉积岩，经历了褶皱和区域变质作用，并被镁铁质-超镁铁质杂岩和各种花岗质岩体侵入。霍宁斯瓦山杂岩体中辉长岩的U-Pb年龄为438.2 ± 0.7Ma，一个伴生花岗岩的U-Pb年龄为438.4 ± 0.9Ma，芬维克花岗岩的U-Pb年龄为437.7 ± 1.6Ma，与化石推断的沉积年龄吻合，表明地质演化非常迅速。过铝质亲合岩体的年龄较晚，分别为436.0 ± 1.0 Ma（SkarsvaBoglag花岗岩）和434.5 ± 1.5 Ma（SkarsvaBoglag推覆体中的花岗质岩墙）。复理石沉积、褶皱和镁铁质-长英质岩浆作用的组合表明形成于沟脊交汇处。这些早志留世事件是一个时期的主要岩浆活动在各种设置所有沿着加里东纪的表达，可能反映了快速收敛和俯冲过程中关闭的Iapetus海洋。重新评估的古地磁签名的Honningsva的Igneous复杂表明，在形成的时候，该套件位于赤道位置，可能接近劳伦边缘，随后向南平移了约1350公里之前和期间侵位到波罗的海边缘。
The Caledonian Magerøy sequence comprises Earliest Silurian clastic metasedimentary rocks, which underwent folding and regional metamorphism and were intruded by a mafic–ultramafic complex and various granitic plutons. U–Pb ages of 438.2 ± 0.7 Ma for gabbro in the Honningsvåg Igneous Complex, 438.4 ± 0.9 Ma for an associated granite and 437.7 ± 1.6 Ma for the Finnvik granite coincide within error with the age of deposition inferred from fossils demonstrating a very rapid geological evolution. Plutons of peraluminous affinity are somewhat younger at 436.0 ± 1.0 Ma (Skarsvåg granite) and 434.5 ± 1.5 Ma (a granitic dyke in the Skarsvåg Nappe). The association of flysch deposition, folding and mafic–felsic magmatism suggests formation at a trench–ridge intersection. These Early Silurian events are the expression of a period of major magmatism in a variety of settings all along the Caledonides, probably reflecting rapid convergence and subduction during closure of the Iapetus Ocean. Re-evaluation of the palaeomagnetic signature of the Honningsvåg Igneous Complex indicates that at the time of formation the suite was located in an equatorial position, probably close to the Laurentian margin, and was subsequently translated southward by some 1350 km prior to and during emplacement onto the Baltic margin.