SH6164 : Palaeozoic dyke

taken 1 year ago, near to Mynydd Llandegai, Gwynedd, Great Britain

Palaeozoic dyke
Palaeozoic dyke
A igneous intrusion, or dyke, penetrating the plum-coloured slates on the Holywell Level. There is significant difference in hardness and tenacity of the igneous rock compared to that of the mudstones which have been metamorphosed to slates. Consequently, during the Caledonian period of mountain-building, the dyke has been fractured and injected with mineralising fluids. Together with its green colouration, this renders it highly visible - though sadly the rock is worthless and will simply go to the tip. The history of deformation allows us to attribute an age to the dyke, which pre-dates the Caledonian and is therefore probably Ordovician and associated with the volcanism which is pervasive in North Wales at that time. Other dyke exposures nearby are highly weathered and reduced to a brownish earth.
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SH6164, 13 images   (more nearby )
  (find more nearby)
Date Taken
Saturday, 15 July, 2017   (more nearby)
Tuesday, 18 July, 2017
Geographical Context
Geological interest  Rocks, Scree, Cliffs 
Primary Subject of Photo
Geological Feature 
Subject Location
OSGB36: geotagged! SH 6121 6410 [10m precision]
WGS84: 53:9.3535N 4:4.6254W
Camera Location
OSGB36: geotagged! SH 6121 6410
View Direction
WEST (about 270 degrees)
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Image Type (about): close look 
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