Great Britain Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! ===Geology=== {{Main|Geology of Great Britain}} Great Britain has been subject to a variety of [[plate tectonic]] processes over a very extended period of time. Changing latitude and sea levels have been important factors in the nature of sedimentary sequences, whilst successive continental collisions have affected [[Geological structure of Great Britain|its geological structure]] with major faulting and folding being a legacy of each [[orogeny]] (mountain-building period), often associated with [[volcanism|volcanic]] activity and the metamorphism of existing rock sequences. As a result of this eventful geological history, the island shows a rich variety of [[landscape]]s. The oldest rocks in Great Britain are the [[Lewisian gneiss]]es, metamorphic rocks found in the far north west of the island and in the [[Hebrides]] (with a few small outcrops elsewhere), which date from at least 2,700 {{Abbreviation|My|million years}} ago. South of the gneisses are a complex mixture of rocks forming the North West [[Scottish Highlands|Highlands]] and [[Grampian]] Highlands in Scotland. These are essentially the remains of folded [[sedimentary rock]]s that were deposited between 1,000 My and 670 My ago over the gneiss on what was then the floor of the [[Iapetus Ocean]]. In the current era the north of the island is rising [[glacial rebound|as a result of]] the weight of Devensian ice being lifted. Counterbalanced, the south and east is sinking, generally estimated at 1 mm ({{frac|1|25}} inch) per year, with the London area sinking at double this partly due to the continuing [[Compaction (geology)|compaction]] of the recent clay deposits. Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page