Of course geology is only part of terroir. Altitude, climate, proximity to ocean, human influence, the weight of the gold: all have vital roles to play. It was obvious this year that while the sub-regions always produce fruit of varying distinction, they don't do the same thing every year. This obviously has as much to do with the way different spots react to different weather patterns throughout the year as it does to the climate differences from one year to another.
A good example is the way the fruit of the young Lyndoch Valley alluviums generally remind me of the pretty florals of northern Beaujolais; think Moulin-à-Vent, Chiroubles and Morgon. The 2013 vintage put these dainties into the Eden Valley wines instead, where the rocks are 500 million years older than that junior Lyndoch dirt. Funny.