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The London-Brabant Massif or London-Brabant Platform is in the tectonic structure of Europe a structural high or massif that stretches from the Rhineland in western Germany across northern Belgium (in the province of Brabant) and the North Sea to the sites of East Anglia and the middle Thames in southern England. The massif also occurs in the Dutch subsurface, where it is bounded to the northeast by the Roer Valley Graben that runs diagonally through Dutch Limburg. The Midlands Craton (southeastern Wales and part of western England) is often considered part of the massif and to reflect this the names Wales–Brabant Massif, Wales–London–Brabant Massif and Wales–Brabant High are sometimes used. The London–Brabant Massif is part of the former microcontinent Avalonia. To the south it borders the Rhenohercynian Zone of the Hercynian orogeny. To the northeast it is flanked by the Anglo-Dutch Basin in the subsurface of the North Sea. At some moments in geologic history the London–Brabant Massif formed an island, which is called the London-Brabant Island. ==Formation== The massif is composed of crystalline basement (metamorphic and igneous rocks) with Proterozoic to early Paleozoic ages. It was deformed and metamorphosed during the Cadomian orogeny (Ediacaran, about ago) and Caledonian orogeny (Silurian, about ). This basement is almost everywhere overlain by younger sedimentary rocks, except for some places in the southwest of England and in Wales. The continent Avalonia was until the Ordovician () part of the large southern continent Gondwana, but then began drifting independently to lower latitudes. As it passed through the dry latitudes represented today by the Namib Desert1, it was eroded and the soils became laterite represented by the Old Red Sandstone which shows its presence in the red soils of Devonshire. The strata, particularly of the Precambrian are complex. Their continuity is also poorly understood because they are beyond the reach of most boreholes. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「London-Brabant Massif」の詳細全文を読む スポンサード リンク
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