Sunday, September 16, 2012

0109 - Geology and enclosures

In the paper quoted in the last post I draw attention to the relation of the decorated Bell Beaker pottery contexts and the geology of South Portugal. At the presentation in the 2005 meeting I showed the following map that clearly shows the concentration of the sites within well defined geological borders.

The middle Guadiana basin, with its geological diversity and good soils and plains, and the poor littoral sandy platform and the schist with wavy topography at the south, making the north limit of the mountains that separate Alentejo from Algarve littoral platform.

Well this same situation can be observed in the enclosures distribution as we know it today (or for the megalithic or hypogeal graves). The line in the map of enclosures marks the same geological limit of the first map. And it speaks for itself: there is a strong connection between the structural geology of south Portugal and the structural aspects of its human occupation.


  1. Fascinating maps, thanks. So we can assume that the Algarve-plus southern hilly region of schist, which was probably at the origin of the "horizons" or "grabsystem" cultural group, was (and is) a very poor region for agriculture and pastoralism, right?

    I presume it would have been better for pastoralism anyhow because cattle and specially sheep adapt better to those poor lands.

    On the other hand, we can say that the regions rich in megalithism, enclosures, bell beaker even were fertile areas where people and tribes were more affluent.

    Still the poor areas of the Algarve and the coast of Baixo Alentejo held in the Chalcolithic what seem to be some towns (as in this map I drew years ago), so they must have got some organized economy going on before the "horizons".

  2. I did not say those territories were unoccupied. I said that the structural geology has connections with the structural human occupations. What we have in the south of Alentejo and in Algarve’s mountains is not the same that we have the the Guadiana and Sado basins. In that area there are (presently known) two small walled enclosures (Cortadouro and Santa Justa) and some megalithic necropolis. Alcalar is at the littoral platform, in a totally different context.
    Regarding Recent Prehistory, all these territories were occupied since the Early Neolithic (to my knowledge, only in the Algarve’ mountains and its northern slopes the Early Neolithic sites are not recorded – but give it time).
    What I am stressing is that during Neolithic and Chalcolithic (what is happening after is not my issue) the different geological and ecological conditions naturally contributed to different human strategies of occupations (and, please, I am not talking about any kind of geographic determinism). So, in a general common frame of Southwest Iberia, we can see diversities and local and sub-regional specificities in interaction.
    Establishing the terms of these interactions is an actual target for reasearch.

    1. In no moment I meant to discuss whether the area was occupied (of course) or unoccupied (of course not). Just trying to gain some further understanding of what these geological conditions implied for the various areas before and after the arrival of the "horizons" group.

      "Establishing the terms of these interactions is an actual target for research".

      I was trying to go faster than researchers (so many questions, so few answers!) but guess that is simply not possible. :)

      Many thanks for your replies in any case.

  3. Those two maps are very powerful in making the point. It is one thing to suppose that there might be a link between enclosures and Bell Beaker relics and the geology, and it is quite another to see it so powerfully and graphically demonstrated with raw data that is marshalled so efficiently.

    Thanks also for the distribution of the geographic landmarks shown on the maps so that the reader can be clear precisely what is depicted.

    The statement regarding the existence of "the poor littoral sandy platform and the schist with wavy topography at the south, making the north limit of the mountains that separate Alentejo from Algarve littoral platform," is an epiphany to me. You can not discern that fact from an ordinary physical map of Iberia. But, it explains so much.