Argentine Malbec from north to south

Our South American Week continues...  See this guide to our recent  South American coverage including many tasting notes

Yesterday, Jancis asked Does Chilean regionality exist?, and I wondered much the same about Argentina. To investigate, I tasted a handful of Malbecs originating from specific areas of the country, from north to south. 

The first impression that such a comparison gives is how reliable a varietal Malbec is. Stylistically it is a boon to MW students, being of consistently remarkable purple hue with a concentrated black fruit character and, often, a floral tone. It might perhaps be confusable with...