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Geological map of eastern Labrador, showing the Grenville and Makkovik Provinces. The bottom inset shows major structural zones in relation to other LITHOPROBE transects studying the Grenville Province elsewhere. The top inset illustrates correlations between the Makkovik Province and the related Ketilidian Mobile Belt of Greenland.

Let's take in the vibrant colours of the map -- a better display than many dress ties would show. The first impression one gets is the contrast between the lower and the upper parts of the map. One sees not only different colours but also contrasting orientations. Both are important. The colours refer to two things: the types and the ages of the rock units they represent (see the legend for this). The contrasting lineations, and the juxtaposition of the variations in colours and directions, originated from the collision of two large cratons. We remember the Grenville Orogen, and how it cut across everything that had existed prior to being thrust upon the pre-existing part of the Canadian Shield. That line of fault thrusting is the one along the "Grenville Front", along which the tectonic styles change so dramatically. One must marvel at the geologists and other earth scientists who contributed to this map. First one finds rocks of various types, then one describes units of them, next places them into their proper structural setting and orientation, and dates them, and then reads all of this as one dynamic story. Note, for instance, how the (red-coloured) Groswater terrane of the Grenville Province overrides two, much older terranes (in purple) of the Makkovik Province. Or see the younger "post-collisional granite plutons" which were intruded into the older rocks of the Pinware terrane (laid bare for us to see by subsequent erosion). At any rate, we get the drift of how much information is contained in such a geological map, and how it takes more than just one discipline to sort out the geological and tectonic situation.

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