2010
SK5210 : Eastern Avalonia
taken 15 years ago, near to Newtown Linford, Leicestershire, England

Eastern Avalonia
See SK5211 : Newton Linford: Leicestershire Yeomanry War Memorial for more about the war Memorial.
Eastern Avalonia? What is he on about. Well the rock outcrops here are what remains of the microcontinent Avalonia. The volcaniclastic rocks were formed in 50+ metre deep sea, made up of sediments washed in from the nearby island arc volcanoes. There is also material like ash that settled from the water column. They show nice turbidite sequences. The chemical makeup of andesite or dacite (my favourite) suggest an island arc near a subduction zone. Geologists compare it to Montserrat. Avalonia was heading north away from Gondwana in the closing Iapetus ocean. This was all 560 million years ago in the Pre Cambrian.
Later the rocks were folded into an anticline (hence the dipping), this was approx 420 ma, just before the Caledonian Orogeny and the collision with Laurentia and Baltica. The rocks by now were 10km down at a temperature of 350 degrees centigrade. Cleavage was produced which can be seen throughout the outcrops, especially Beacon hill.
SK5014 : Beacon Hill Hornstone crag
Info from the BGS Link
(Archive Link
)
Eastern Avalonia? What is he on about. Well the rock outcrops here are what remains of the microcontinent Avalonia. The volcaniclastic rocks were formed in 50+ metre deep sea, made up of sediments washed in from the nearby island arc volcanoes. There is also material like ash that settled from the water column. They show nice turbidite sequences. The chemical makeup of andesite or dacite (my favourite) suggest an island arc near a subduction zone. Geologists compare it to Montserrat. Avalonia was heading north away from Gondwana in the closing Iapetus ocean. This was all 560 million years ago in the Pre Cambrian.
Later the rocks were folded into an anticline (hence the dipping), this was approx 420 ma, just before the Caledonian Orogeny and the collision with Laurentia and Baltica. The rocks by now were 10km down at a temperature of 350 degrees centigrade. Cleavage was produced which can be seen throughout the outcrops, especially Beacon hill.
SK5014 : Beacon Hill Hornstone crag
Info from the BGS Link
