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首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >The flexural rigidity of Fennoscandia: reflection of the tectonothermal age of the lithospheric mantle
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The flexural rigidity of Fennoscandia: reflection of the tectonothermal age of the lithospheric mantle

机译：Fennoscandia的抗弯刚度：岩石圈地幔构造热时代的反映

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Estiamtes of effective elastic thickness (Te), a measure of the strength of the plate, have shown that older and cool cratonic regions are characterised by a stronger lithosphere (higher Te values) than areas which have been tectonically reworked. We use geophysical data and information from xenoliths in volcanic rocks from Fennoscandia and show that the strength of the lithosphere reflects the tectonothermal age of the lithospheric mantle. Fennoscandia is made up of the Baltic shield (1.9-3.0 Ga) and the Caledonian Orogen of Norway and northern Sweden (400-500 Ma). The shield is characterised by an old, thick and cold lithosphere in contrast to the Caledonides where the lithosphere is hotter and thinner. Our geophysical analysis results show a regional variation in elastic plate thickness from 8 km to 70 km, or equivalently, a flexural rigidity between 0.4 * 10~(22) and 3 * 10~(24) Nm. These results suggest that the lithosphere is strongest in the relatively stable Archaean Province, weaker in the regions characterised by Proterozoic crustal formation, and lowest in the tectonically reworked and deformed Caledonian belt. Within the study area, there is a direct correlation between lithosphere strength, the age of the last major tectonothermal event registered in the crust and lithospheric mantle composition. These broad correlations reflect thinner and more fertile lithosphere, and higher geothermal gradients, beneath regions of progressively younger crust.
机译：有效弹性厚度（Te）的强度（衡量板强度的指标）表明，较老的和较冷的克拉通区域的特征是岩石圈比经过构造改造的区域更坚固（Te值更高）。我们利用芬诺斯坎迪亚火山岩中的异质岩中的地球物理数据和信息，表明岩石圈的强度反映了岩石圈地幔的构造热年龄。 Fennoscandia由波罗的海盾（1.9-3.0 Ga）和挪威和瑞典北部的加里东造山带（400-500 Ma）组成。盾构的特点是旧的，厚而冷的岩石圈，而Caledonides则是岩石圈更热更薄的地方。我们的地球物理分析结果显示，弹性板厚度从8 km到70 km发生区域变化，或者等效地，弯曲刚度在0.4 * 10〜（22）和3 * 10〜（24）Nm之间。这些结果表明，岩石圈在相对稳定的古生界省中最强，在以元古代地壳形成为特征的区域中较弱，而在构造改造和变形的加里东带中最低。在研究区域内，岩石圈强度，地壳中记录的最后一次重大构造热事件的年龄与岩石圈地幔成分之间存在直接关系。这些广泛的相关性反映了在地壳逐渐年轻化的区域之下，岩石圈更薄更肥沃，地热梯度更高。

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