Volcanoes
March 29th, 2008 | 
Author: Following on from our fantastic experiments at CLAS, I have been wondering if there was any mountains in britain which were currently volcanic, or which could in theory erupt?
In answer to this quest I came across this:
The variation in Ordovician volcanic rocks of Wales and the Lake District imply convergent plate boundary with subduction occurring to the north of these areas, southwards under the Lake District and Wales. There was a lot of volcanic activity in Wales. Many of the lavas erupted were erupted under the sea and mixed with the sediments on the sea floor, as did the large flows of volcanic subaerial ash, known today as nuées ardentes.
The convergent plates, subduction and volcanic activity resulted in the formation of the Caledonian mountain chain that runs from Wales up through Scotland and into Scandinavia. What we see now is the eroded core of these mountains.
The main centres of volcanic activity were Snowdonia, the Arenigs, (just south of Snowdonia) Cader Idris (just south of the Arenigs) and Prescelly (near the southern bit of Cardigan bay).
Other evidence for associated volcanic activity comes form the southern uplands of Scotland and Ireland.
link Accessed March 08
The Ordovician period is the second of the six periods of the Paleozoic era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago (ICS, 2004)[1].
It follows the Cambrian period and is followed by the Silurian period. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879, to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in northern Wales into the Cambrian and Silurian periods respectively. Lapworth, recognizing that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian periods, realized that they should be placed in a period of their own.
While recognition of the distinct Ordovician period was slow in the United Kingdom, other areas of the world accepted it quickly. It received international sanction in 1906, when it was adopted as an official period of the Paleozoic era by the International Geological Congress.
Lava is molten rock expelled by a volcano during an eruption. When first expelled from a volcanic vent, it is a liquid at temperatures from 700 °C to 1,200 °C (1,300 °F to 2,200 °F). Although lava is quite viscous, with about 100,000 times the viscosity of water, it can flow great distances before cooling and solidifying, because of its thixotropic and shear thinning properties
Interesting!!
Popularity: 32% [?]
