Wales-London-Brabant Massif

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 Belgian subsurface, where it is bounded to the northeast by the Roer Valley Graben that runs diagonally through Dutch Limburg.

The Midlands Microcraton (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.

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 600 million years ago ago) and Caledonian orogeny (Silurian, about 420 million years ago). This basement is almost everywhere overlain by younger sedimentary rocks, except for some places in the southwest of England and in Wales.

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