J2105 : Sand martin nesting holes in the sandy horizons of the cliffs west of Cooley Point

taken 6 years ago, 6 km S of Greenore, Co Louth, Ireland

Sand martin nesting holes in the sandy horizons of the  cliffs west of Cooley Point
Sand martin nesting holes in the sandy horizons of the cliffs west of Cooley Point
This is a good examples of bioerosion (erosion of rock by living organisms). Colonies of Sand martins excavate holes in the sandy horizons in the cliff face in which to lay their eggs. These tunnels can range in depth from a few inches to several feet.
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Cooley Point

The 6m high cliffs running some 400m between Templetown and Cooley Point are the product of glaciomarine sedimentation some 15,000BP. The cliffs exhibit four distinct layers.

1] basal mud facies, some 1.5m thick, deposited from sediment plumes after the initial retreat of the ice. These marine deposited muds are fossiliferous and contain the remains of minute Arctic fauna including Elphidium clavatum and Roundstoniaglobulifera.

2]Above the mud is a tightly packed boulder pavement only one clast thick formed of local Carboniferous rocks which has been pressed into the mud below. It is the product of intertidal activity at a period of ice readvance. The boulders would have been transferred to the area on ice flows which melted depositing their load on the sea bed.

3] A layer of laminated sand and mud deposited by glacial meltwater. These are ground up sandstone and this would suggest that their source origin was the Dundalk Bay ice lobe. Cross bedding is common in this layer.

4] An overlying gravel layer laid down by glacial melt water.


Following the Ice Age. the coastal areas of the Cooley Peninsula were subject to isostatic uplift leading to the formation of raised beaches which are in the process of being eroded by the sea.

Creative Commons Licence [Some Rights Reserved]   © Copyright Eric Jones and licensed for reuse under this Creative Commons Licence.
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J2105, 58 images   (more nearby search)
Photographer
Date Taken
Friday, 27 October, 2017   (more nearby)
Submitted
Wednesday, 15 November, 2017
Geographical Context
Coastal  Geological interest  Wild Animals, Plants and Mushrooms  Rocks, Scree, Cliffs 
Subject Location
Irish: geotagged! J 218 051 [100m precision]
WGS84: 53:58.8915N 6:8.5751W
Camera Location
Irish: geotagged! J 218 051
View Direction
WEST (about 270 degrees)
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Image Type (about): geograph 
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