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 times 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) 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.
The continent Avalonia was until the Ordovician ( 465 million years ago) 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 Desert 1 , it was eroded and the soils became laterite. The strata, particularly of the Precambrian are complex. Their continuity is also poorly understood because they are beyond the reach of most boreholes.
The period from which the island has exercised most economic influence on modern Europe was the Carboniferous. As the continent was drifting past the Equator, on the island's shores, there grew a rich tropical forest swamp. On the island's southern shore, it left the Dinantian, Namurian and Westphalian coal fields of France, Belgium and western Germany. See Aachener Revier (in German).
To its northwest, the thinner crust between it and the Market Weighton Axis was crumpled between the blocks leaving low ridges of wet land between strips of water such as the Widmerpool Gulf. On the wet land, the coal fields of Leicestershire, Nottinghamshire and Derbyshire were deposited. These extend further east but are now at ever greater depth. At the modern east Yorkshire and north Lincolnshire coast for example, their upper surface is at about 2 km depth. These Carboniferous beds are part of a system linking with those of Westphalia, around the north side of the island. On the north Norfolk coast, the line of the Carboniferous shore roughly coincides with the modern one. 2
As the continent drifted northwards, away from the Equator, through the latitudes represented today by the Sahara desert, the erosion was renewed. This time, the lateritic soils are represented by the New Red Sandstone and the red soils of Leicestershire and Rutland.
The early Permian was the time of the height of the Variscan earth movements as the crust to the south was crushed against the island. The great disturbances seen at the surface in Brittany, the Ardennes and the Rhineland also lie below the Paris Basin. They fade out in the gentler anticline of the downs and Weald of southern England which overlies the edge of the island. The axis of this anticline is normally called the northern Variscan front. However, the chalk of the downs is Upper Cretaceous, so the process continued well after the Permian. The point in the present context is that the stability of the island contrasts with the relatively unstable crust to its south, which was forced into a long mountain ridge.
To the north, economically important things were happening. Western Britain was pushed up as part of the Variscan Orogeny while the east of Britain, including the island began to subside leaving a broad basin, north of the island and south of Scandinavia. This formed a shallow sea in a very dry climate. Desert sands and salt basins were a result but there are also mudstones. This provided the alternating porous and impervious rocks which have trapped the gas escaping when the coal measures, below were subjected to geothermal heat. This has left a group of gas fields off the Norfolk coast. That is to say, off the coast of the island.
In the early Jurassic, the Rhaetic sea flooded much of the Permian plain. On the margin of the London-Brabant Island, the estuarine conditions which left the Lower Estuarine Series prevailed for a while before the sea rose so as to deposit the Lincolnshire limestones before falling again so that the Upper Estuarine Series was left. Again the sea rose to deposit the Blisworth Limestone, the Blisworth Clay and the Upper Jurassic clays.
The same general pattern occurred in France leaving the Paris Basin flooded from Anjou to Luxembourg.
By the Cretaceous the island had sunk much further in relation to the sea level. Before the end of the period, the British end was buried in Upper Cretaceous chalk. This happened because the Pacific Ocean bed swelled up causing the world's seas to rise but also, the process released much carbon dioxide.
It is now best viewed as a block of dense crust floating deeply sunk into the mantle and overlain with less dense superficial rocks. It depresses the boundary of the crust and the mantle (Mohorovičić discontinuity, commonly Moho) to depths greater than 40 kilometres as against a figure at the top of the continental shelf of about thirty and less than fifteen below oceanic depths. 3
The map shows that there is some tendency for such seismic activity as there is in the region, to occur around the margin of the massif. It was into this pattern that the Dover Straits earthquake of 1580 and the 2008 Lincolnshire earthquake, the latter marked by an orange star, fell.
The geology of Great Britain is renowned for its diversity. As a result of its eventful geological history, Great Britain shows a rich variety of landscapes across the constituent countries of England, Wales and Scotland. Rocks of almost all geological ages are represented at outcrop, from the Archaean onwards.
Avalonia was a microcontinent in the Paleozoic era. Crustal fragments of this former microcontinent underlie south-west Great Britain, southern Ireland, and the eastern coast of North America. It is the source of many of the older rocks of Western Europe, Atlantic Canada, and parts of the coastal United States. Avalonia is named for the Avalon Peninsula in Newfoundland.
The Caledonian orogeny was a mountain-building era recorded in the northern parts of the British Isles, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occurred from the Ordovician to Early Devonian, roughly 490–390 million years ago (Ma). It was caused by the closure of the Iapetus Ocean when the continents and terranes of Laurentia, Baltica and Avalonia collided.
The Variscan or Hercynianorogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea.
The Rheic Ocean was an ocean which separated two major palaeocontinents, Gondwana and Laurussia (Laurentia-Baltica-Avalonia). One of the principal oceans of the Palaeozoic, its sutures today stretch 10,000 km (6,200 mi) from Mexico to Turkey and its closure resulted in the assembly of the supercontinent Pangaea and the formation of the Variscan–Alleghenian–Ouachita orogenies.
The Paris Basin is one of the major geological regions of France. It developed since the Triassic over remnant uplands of the Variscan orogeny. The sedimentary basin, no longer a single drainage basin, is a large sag in the craton, bordered by the Armorican Massif to the west, the Ardennes-Brabant axis to the north, the Massif des Vosges to the east, and the Massif Central to the south.
The geology of Australia includes virtually all known rock types, spanning a geological time period of over 3.8 billion years, including some of the oldest rocks on earth. Australia is a continent situated on the Indo-Australian Plate.
The geology of England is mainly sedimentary. The youngest rocks are in the south east around London, progressing in age in a north westerly direction. The Tees–Exe line marks the division between younger, softer and low-lying rocks in the south east and the generally older and harder rocks of the north and west which give rise to higher relief in those regions. The geology of England is recognisable in the landscape of its counties, the building materials of its towns and its regional extractive industries.
The geology of the Iberian Peninsula consists of the study of the rock formations on the Iberian Peninsula, which includes Spain, Portugal, Andorra, and Gibraltar. The peninsula contains rocks from every geological period from the Ediacaran to the Quaternary, and many types of rock are represented. World-class mineral deposits are also found there.
The Rhenohercynian Zone or Rheno-Hercynian zone in structural geology describes a fold belt of west and central Europe, formed during the Hercynian orogeny. The zone consists of folded and thrust Devonian and early Carboniferous sedimentary rocks that were deposited in a back-arc basin along the southern margin of the then existing paleocontinent Laurussia.
The geology of the North Sea describes the geological features such as channels, trenches, and ridges today and the geological history, plate tectonics, and geological events that created them.
The geological structure of Great Britain is complex, resulting as it does from a long and varied geological history spanning more than two billion years. This piece of the Earth's crust has experienced several episodes of mountain building or 'orogenies', each of which has added further complexity to the picture.
The Pyrenees are a 430-kilometre-long, roughly east–west striking, intracontinental mountain chain that divide France, Spain, and Andorra. The belt has an extended, polycyclic geological evolution dating back to the Precambrian. The chain's present configuration is due to the collision between the microcontinent Iberia and the southwestern promontory of the European Plate. The two continents were approaching each other since the onset of the Upper Cretaceous (Albian/Cenomanian) about 100 million years ago and were consequently colliding during the Paleogene (Eocene/Oligocene) 55 to 25 million years ago. After its uplift, the chain experienced intense erosion and isostatic readjustments. A cross-section through the chain shows an asymmetric flower-like structure with steeper dips on the French side. The Pyrenees are not solely the result of compressional forces, but also show an important sinistral shearing.
The North Sea basin is located in northern Europe and lies between the United Kingdom, and Norway just north of The Netherlands and can be divided into many sub-basins. The Southern North Sea basin is the largest gas producing basin in the UK continental shelf, with production coming from the lower Permian sandstones which are sealed by the upper Zechstein salt. The evolution of the North Sea basin occurred through multiple stages throughout the geologic timeline. First the creation of the Sub-Cambrian peneplain, followed by the Caledonian Orogeny in the late Silurian and early Devonian. Rift phases occurred in the late Paleozoic and early Mesozoic which allowed the opening of the northeastern Atlantic. Differential uplift occurred in the late Paleogene and Neogene. The geology of the Southern North Sea basin has a complex history of basinal subsidence that had occurred in the Paleozoic, Mesozoic, and Cenozoic. Uplift events occurred which were then followed by crustal extension which allowed rocks to become folded and faulted late in the Paleozoic. Tectonic movements allowed for halokinesis to occur with more uplift in the Mesozoic followed by a major phase of inversion occurred in the Cenozoic affecting many basins in northwestern Europe. The overall saucer-shaped geometry of the southern North Sea Basin indicates that the major faults have not been actively controlling sediment distribution.
The North German Basin is a passive-active rift basin located in central and west Europe, lying within the southeasternmost portions of the North Sea and the southwestern Baltic Sea and across terrestrial portions of northern Germany, Netherlands, and Poland. The North German Basin is a sub-basin of the Southern Permian Basin, that accounts for a composite of intra-continental basins composed of Permian to Cenozoic sediments, which have accumulated to thicknesses around 10–12 kilometres (6–7.5 mi). The complex evolution of the basin takes place from the Permian to the Cenozoic, and is largely influenced by multiple stages of rifting, subsidence, and salt tectonic events. The North German Basin also accounts for a significant amount of Western Europe's natural gas resources, including one of the world's largest natural gas reservoir, the Groningen gas field.
The geology of Germany is heavily influenced by several phases of orogeny in the Paleozoic and the Cenozoic, by sedimentation in shelf seas and epicontinental seas and on plains in the Permian and Mesozoic as well as by the Quaternary glaciations.
The geology of Belgium encompasses rocks, minerals and tectonic events stretching back more than 500 million years. Belgium covers an area of about 30,507 square kilometers and was instrumental in the development of geology. The extensive outcrops in Belgium became the standard reference points in stratigraphy as early as the mid-19th century. Some of them are internationally recognized features related to the Carboniferous and the Devonian periods. These rocks were folded by two orogeny mountain building events --the Hercynian orogeny, and Caledonian Orogeny. Paleozoic basement rocks cover much of the country and are overlain by Mesozoic and Cenozoic sediments.
The geology of the Czech Republic is very tectonically complex, split between the Western Carpathian Mountains and the Bohemian Massif.
The geology of the Gower Peninsula in South Wales is central to the area's character and to its appeal to visitors. The peninsula is formed almost entirely from a faulted and folded sequence of Carboniferous rocks though both the earlier Old Red Sandstone and later New Red Sandstone are also present. Gower lay on the southern margin of the last ice sheet and has been a focus of interest for researchers and students in that respect too. Cave development and the use of some for early human occupation is a further significant aspect of the peninsula's scientific and cultural interest.