This interactive map is, like most of the other maps on this site, built in layers which can individually be switched on and off. The map can be zoomed in and out by use of the + and – buttons in the top left, or by the use of a mouse wheel.
The legend for all layers is found by moving the mouse pointer over the icon in the top right. Layers lie one on top of another, so the lower layers will be overlain by those higher in the legend. The map is displayed within it's own frame and can be moved by dragging with the left mouse button depressed.
Clicking anywhere on the map will raise a popup box that describes the layers active at that point, in sequence, from the topmost to the lowest.
The layers on the map show, alternately,
This map represents an exercise in time travel, and is fraught with problems. But it is a fun exercise.
The coastline portrays south west Ireland - our focus is on West Cork, but this has been extended because of the association with the Munster Basin - but south west Ireland of about 380 million years ago. This is a plainspastic reconstruction, that is, the crushing and shortening effect of folding and faulting in the intervening years has been undone. So the map is stretched by about 150% in a NS direction, as it was before plate movements put the squeeze on.
The map has been designed to show the progressive changes in environment - subtle though they were most of the time - that occurred over the roughly 80 million years, from the Mid Devonian through to the Mid to Late Carboniferous periods, during which the rocks that currently form the bedrock of West Cork were being deposited as sediment.
The map initially displays the position of landscape elements as the deposition of the sediments that were to become the rocks of West Cork was just starting. The basement rocks were probably of similar type and deposited in a similar environment to what we see as the deposition sequence starts. To the north note the high ground - mountains in the area of what is now Dingle Bay. Fans of rock fragments and coarse sand and gravel where flood water and rivers issue out of the mountains heading south, and underneath that, a major fault where the earth's crust lying to the south is gradually sinking.
To east and west the substantial blocks of granite (the one in the west is conjectural based on gravity measuremnts) stabilised the crust, and so the subsidence of the basin did not extend here.
Note particularly the northward movement of the coastline and the change from terrestrial environments to coastal and then marine environment. Again, this map is just a representation in very broad outline of what we think happened.
How to use this map
With all layers switched off as the map is when first displayed, switch on the numbered layers starting at 1. You can switch on the intervening layers as you progress. Clicking on the areas that display on the map will give descriptions of the environment, and the names and geological symbols of the formations that they gave rise to. All the formations grouped together under one name are considered to be more or less from the same time period. Thus moving up the numbered layers in sequence will give a view of the environments of deposition progressing through time. The popup boxes that display when you click on the map will show the layers trhat are active at that point. To read these in chronological order, start at the bottom.
Having reached the top - layer 18 - and investigated all the different environments that occurred at different times in the different places, now switch off all the numbered layers and leave all the others on. The result will be a geological map of the surface outcrops of the main formations.
The map has been generated, using a program called QGIS2Web, from an Open Source GIS called QGIS. This software is constantly being improved and, like all open source products, is highly efficient and free. The layers have all originated from data made freely available to the public domain. There are some inconsistencies in the map, arising partly through the different sources the data came from not being in alignment either with accuracy, completeness or definition.
Read more about how these maps are made and where the data comes from.Copyright © 2020 - All Rights Reserved - www.westcorkpalaeo.com
Copyright statements for map data - the map pages
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