Geography in United Kingdom

The UK has a coastline which measures about 12,400 km. The heavy indentation of the coastline helps to ensure that no location is more than 125 km from tidal waters.
In total, it is estimated that the UK is made up of over one thousand small islands, some being natural and some being man-made crannogs, which were built in past times using stone and wood and which were enlarged by natural waste building up over time.
The United Kingdom of Great Britain and Northern Ireland, or UK, is in Northern Europe and or Western Europe. It comprises the island of Great Britain (England, Scotland and Wales) and the northeastern one-sixth of the island of Ireland (Northern Ireland), together with many smaller islands. The mainland areas lie between latitudes 49°N and 59°N (the Shetland Islands reach to nearly 61°N), and longitudes 8°W to 2°E. The Royal Greenwich Observatory, in South East London, is the defining point of the Prime Meridian.

The UK lies between the North Atlantic Ocean and the North Sea, and comes within 35 km of the northwest coast of France, from which it is separated by the English Channel. Northern Ireland shares a 360 km international land boundary with the Republic of Ireland.

The total area of the United Kingdom is approximately 245,000 square kilometres comprising of the island of Great Britain, the northeastern one-sixth of the island of Ireland (Northern Ireland) and smaller islands. England is the largest country of the United Kingdom, at 130,410 square kilometres accounting for just over half the total area of the UK. Scotland at 78,772 square kilometres, is second largest, accounting for about a third of the area of the UK. Wales and Northern Ireland are much smaller, covering 20,758 square kilometres and 14,160 square kilometres respectively.
The physical geography of the UK varies greatly. The Geography of England consists of lowland terrain, with mountainous terrain north-west of the Tees-Exe line including the Cumbrian Mountains of the Lake District, the Pennines and limestone hills of the Peak District, Exmoor and Dartmoor. The Geography of Scotland is distinguished by the Highland Boundary Fault – a geological rock fracture – which traverses the Scottish mainland from Helensburgh to Stonehaven. The faultline separates the two distinctively different regions of the Highlands to the north and west and the lowlands to the south and east. The Geography of Wales is mostly mountainous, though south Wales is less mountainous than north and mid Wales. The Geography of Ireland includes the Mourne Mountains as well as Lough Neagh, at 388 square kilometres, the largest body of water in the UK and Ireland.

The geology of the United Kingdom is varied and diverse. This gives up to the wide variety of landscapes found across the UK. This variety, coupled with the early efforts of UK based scientists and geologists to understand it, has influenced the naming of many geological concepts, including many of the geological periods (for example, the Ordovician period is named after the Ordovices, a people of early Britain; the Devonian period is named after the county of Devon in south-west England).

The remains of ancient volcanic islands underlie much of central England with small outcrops visible in many places. Around 600 Ma, the Cadomian Orogeny (mountain building period) caused the English and Welsh landscape to be transformed into a mountainous region, along with much of north west Europe.

The Welsh Skiddaw slate deposits formed at around 500 Ma, during the Ordovician Period. At about this time, around 425 Ma, north Wales (and south Mayo in Ireland) experienced volcanic activity. The remains of these volcanoes are still visible, for example Rhobell Fwar, dating from 510 Ma. Large quantities of volcanic lava and ash known as the Borrowdale Volcanics covered both Wales and the Lake District, still seen in the form of mountains such as Helvellyn and Scafell Pike.
Volcanic deposits formed Ben Nevis in the Devonian Period. Sea levels varied considerably, with the coastline advancing and retreating from north to south across England, and with the deposition of numerous sedimentary rock layers. The Old Red Sandstone of Devon gave the period its name, though deposits are found in many other places.

In the Cretaceous Period, much of the UK was again below the sea and chalk and flints were deposited over much of Great Britain. These are now notably exposed at the White Cliffs of Dover, and form Salisbury Plain, the Chiltern Hills, the South Downs and other similar features.
The last volcanic rocks in the UK were formed in the early Tertiary Period, between 63 and 52 Ma, with the major eruptions that formed the Antrim Plateau and the basaltic columns of the Giant's Causeway. Further sediments were deposited over southern England, including the London clay, while the English Channel consisted of mud flats and river deposited sands.

The major changes during the last few million years, during the Quaternary Period, have been brought about by several recent ice ages, leaving a legacy of U-shaped valleys in highland areas, and fertile soil in southern U.K.

The UK has a coastline which measures about 12,429 km. The heavy indentation of the coastline helps to ensure that no location is more than 125 km from tidal waters.