0115 - New papers on Portuguese ditched enclosures

With free download here.

Helmut Becker e António Carlos Valera

LUZ 20 (MOURÃO, ÉVORA): RESULTADOS PRELIMINARES DA PROSPEÇÃO GEOFÍSICA (MAGNETOMETRIA DE CÉSIO)
Luz 20 (Mourão, Évora): preleminary results of geophysical survey (caesium magnetometry)

Helmut Becker, António Carlos Valera e Patrícia Castanheira

MONTE DO OLIVAL 1 (FERREIRA DO ALENTEJO, BEJA): MAGNETOMETRIA DE CÉSIO NUM RECINTO DE FOSSOS DO 3º MILÉNIO AC.
Monte do Olival 1 (Ferreira do Alentejo, Beja). Caesium magnetometry in a ditched enclosure from the 3^rd millennium BC.

António Carlos Valera

“ÍDOLOS ALMERIENSES” PROVENIENTES DE CONTEXTOS NEOLÍTICOS DO COMPLEXO DE RECINTOS DOS PERDIGÕES.
“Almeriense Idols” from Neolithic contexts of the enclosures complex of Perdigões

0114 - What to do with them

This is a question that should be asked more often. There are too many enclosures excavated and neglected, with their structures exposed to the natural elements and anthropic ones. This is not a specificity of prehistoric enclosures, but it is a major problem in their communication. Difficult to interpret and to communicate to the general public, the conditions of the few that are available for public visiting in Portugal are depressing, and definitely not concurring for public awareness of the importance of this kind of heritage and public mobilization for its value, defence and preservation.

When we follow a sign and find this...

 

Walled enclosure of Monte da Tumba (Torrão), visited two weeks ago.

... what really should we think? If we cannot afford the preservation of an enclosure for public visiting in positive conditions, than we should be aware that presenting them in unacceptable conditions is just stupid, for we will be sending all the wrong messages I can imagine.  This situation is generalized. Sometimes we can see that local authorities take some care of this heritage, but generally with local resources, not using experts on the matter. But even that is rare. Abandonment is the norm.

If the country doesn’t have the means for keeping these sites presentable, because there is no money, because there is not enough cultural market for archaeological heritage, then maybe it is better to cover some of them: the ones that don’t have any kind of regular concern.
 

Maybe confronted with that, local, regional and national spirits would have a different attitude to find the means or assume that is just impossible.

0113 - Dating ditches and funerary practices

Tomorrow, at the VI Archaeological Meeting of Southwest Iberia, a paper will be presented about a radiocarbon sequence of dates for Perdigões set of enclosures.

“Valera, A.C, Silva, A.M. & Márquez Romero, J.E., “The temporality of Perdigões enclosures: absolute chronology of structures and practices”.

This sequence, of 34 dates, was obtained in the course of three projects integrated in the Global Programme of Research of Perdigões, coordinated by the NIA-ERA: a project of NIA-ERA aiming precisely to established the temporalities of the set of enclosures; a project of the Department of Anthropology of Coimbra University in collaboration with NIA-ERA dedicated to funerary practices in Perdigões; a project of the Malaga University developed in the NE gate of the outside enclosure.

The sequence reveals an occupation of more than a millennia, between 3360 and 2100 BC, corresponding to the Late Neolithic, Chalcolithic and transition to the Bronze Age. It also reveals a provisory image of progressive enlargement of the site during this time span and the progressive diversity of funerary practices, especially during the third millennium BC.

We will be coming back to this important chronological sequence during the meeting taking place in next November in Lisbon on enclosures and funerary practices.

And we hope to publish it next year.

0112 - Interpreting geophysics

Here is the image of the magnetogram of the ditched and palisade enclosure of Monte do Olival 1 with Helmut Becker’s interpretation of the negative structures present at the site. This interpretation will be published next month in the electronic journal Apontamentos de Arqueologia e Património (a free download journal).

One of the things we learn with Helmut is that having a magnetogram is not enough. We also need good interpretation, based on the knowledge of geophysics, but also of the type of contexts we are dealing with.

0111 - Re-excavating ditches

Sections of the outside ditch at Bela Vista 5:a previous layer was excavated in the centre and after refilled with other deposits.

This is, in a certain way, another version of overlapped ditches problem. In fact, it is frequent to record evidences of ditches that were reopened, by the re-excavation of part of its previous fillings. It is important to notice that only when the reopening is partial is it

detectable by archaeology. The total remove of previous filling deposits leaves no evidence, and if they occurred, then these activities would have been even more common.

This creates problems to ditch dating, because there might be a significant time between the initial excavation of a ditch and its last filling sequence. Only with several sections and good dating sequences we can evaluate these problems.

But another problem is why they reopened some ditches? And why frequently just a central part of the ditch, leaving a ditch with “walls of sediment”? Is it because they want to rapidly fill it again with new deposits and materials? They must have done so, otherwise those “walls of sediment” would have been eroded (and we can clearly see them in some sections, like the one presented here).

This kind of stratigraphic sequences points to human intentionality in the formation of the deposits inside ditches, not just because of the materials or the structured organization they might present. The structure of the deposits itself may be an argument to that intentionality.

0110 - Overlapping ditches

This is an important issue for ditched enclosures understanding that hasn’t been researched as it deserves in Iberia. Here is a situation from Perdigões that we just started to approach.

 In sector P we open an area to research the overlapping of ditches 7 and 8. The first observation is that, contrary to what we assumed by the geophysics magnetogram, ditch 8 is older than ditch 7. In fact, it is ditch 7 that cuts ditch 8, and partially “walks over it” in the excavated section.

 

 

And that is really odd. Why open a ditch (which implies a lot of work and effort) in the bed rock, and then cut just partially, in small distances, a previous ditch? Why not use more of that previous ditch?  Or, why not fully avoid that previous ditch?

It seems that they just wanted to cut a new ditch, with a wavy plan, with no regard to previous ditch 8. But, if we look to the magnetogram, ditch 8 is a concentric mach to previous ditch 6. And why the ditch has part f its trajectory inside ditch 7, and then sudden  get outside, and then curved to be over it, just to get in again?

The conclusion is that no easy modern rational explanation can deal with these strange practices of opening ditches at Perdigões. We must keep our minds opened in the presence of these enclosed spaces.  The previous seems to condition the posterior, but in very complex ways not easy to explain.

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.

 

 

0108 - Ditches and Bell Beakers

Bell Beakers are not common in Portuguese ditched enclosures. Well, in the small ones. There, they are virtually unknown. Even in those built in bell beaker times.

But at the enclosures that grew bigger, to became large ones, like Perdigões and Porto Torrão, beakers are present and they can be very well represented (as it happens in Porto Torrão).

But that is not it. A pattern emerged in the last years. In small sites, sometimes reoccupations of walled enclosures (but never ditched ones), we tend to have beakers of a mono style (maritime, or incise, or combed geometric). But the large ditched enclosures are the only ones where we have all these styles together.

A paper of mine has recently been published on this issue here.

Notice that in the maps, Perdigões is told to only have maritime and incised beakers. Well, this summer things changed, and combed geometric beakers also are present.

In fact, as Perdigões, Porto Torrão and Bela Vista 5 chronologies show, at beaker times ditches were still being built in west Iberia. Sometimes enlarging previous enclosures (like in Perdigões), sometimes creating original enclosures (like at Bela Vista 5).

But only in the big ones we have the presence of the three main styles. Another sign of the social role of these large enclosures.

0107 - The small enclosure of Carrascal (Porto Torrão)

It was a project developed by Era Arqueologia, and the geophysics was, of course, done by Helmut Becker with the results he usually provides.

Just 800 meters way from Porto Torrão traditional limits, and associated to a large area of necropolis, here is a small and perfectly circular ditched enclosure, with just 20m diameter.

A gate is visible at NW, possible orientated to sunset summer solstice.

At Porto Torrão things are much more complex than everybody expected and, I would argue, still expect.

0106 - “Idols” in ditches

Is the second situation in Perdigões, separated from the first one by more the 500 hundred years: the depositions of idols in the bottom of ditches.

The first situation was detected in ditch 1 (Mata et al., 2011), dated from de second half of the 3rd millennium BC. A schist idol, with lateral cuts, was found deposited just at the bottom of the ditch, associated to a complete pot and some faunal remains.

 

 

Idol in Ditch 1 (After Mata et al. 2011)

 

The second situation was recorded this year, in ditch 12, dated from Late Neolithic. An assemblage of 5 Almeriense Idols was recovered at the bottom of the ditch. I am just finishing a paper on this context that will be published next October.

 

Idols in ditch 12.

These situations, although apart in time, document a same general fact: the filling of the ditches was, frequently, the result of intentional human action and they might document a ritualization of the beginning of those processes. Unless we admit they were just lost by someone passing by.

More and more evidences are appearing every year to create problems to the “erosion” and “garbage” explanations of ditch fillings and to support other interpretations that take into account human activity and intentionality.  

References:

Mata, E., Fernández, J. e Caro, J.L. (2011), "Figurinha en xisto procedente del relleno del foso 1 del complexo arqueológico dos Perdigões (Reguengos de Monsaraz", Apontamentos de Arqueologia e Património, 7, NIA-ERA, p.19-21.

0105 - Bela Vista 5

Location: Beja municipality, Beja district, Alentejo, South Portugal)
Chronology: Late Chalcolitic /Early Bronze Age

Bibliographic references: unpublished.

The archaeological materials, namely the pottery, already suggested that this enclosure would be a later one in the context of Iberian ditched enclosures (see post 96).

Radiocabon recently confirmed that idea, by putting the ditches in the last three hundred years of the 3^rd millennium BC.

But there are earlier pits and pits later than this time span, so the enclosure was added to an already existing site and pits continued to be built after the ditches were filled.

And not far (less than a kilometre to East and to West), necropolis of hipogea from Late Neolithic and Bronze Age were detected and excavated.

0104 - Enclosures and abandonment (1)

The walled enclosure of Monte da Tumba (Torrão, Alentejo) is a good example of an intermediate abandonment in a site that originally (Silva & Soares, 1987) was considered to have a continuous sequence of occupation. 

Image taken from: http://al-qasr-abu-danis.blogspot.pt/2009/04/accao-de-sensibilizacao-povoado-do.html

“The potent stratigraphic sequence of Phase I is interrupted by also potent wall ruins. Over these ruins a new occupation phase took place and new constructions are built. In this phase, a house seems to have been burned and the roof has fallen, preserving a material assemblage in good state. New ruins are then identified and a new (3rd) phase is defined, also with new constructions, like a central tower. According to the excavators, this sequence of continuous occupation is of 500 years.”

“In this discourse, no temporary abandonments were considered. In reality, it is not probable that two moments where powerful wall ruins are formed over which new construction are built and substantial changes in material culture can be observed (like the appearance of copper metallurgy in Phase 2 or the bell beakers in phase 3) didn’t implied interruptions in the occupation of the site. Ruins and generalized destructions as described do not happen in a day (unless by catastrophe) fallowed by a new occupation next day, with new constructions, new technologies and new artefacts previously inexistent. And we must remember we are talking about 500 years.”

(taken from Valera, 2003)

In fact, this sequence clearly suggests the existence of periods of abandonment in the sequence of occupation of the site. Determine the reasons of those abandonments, their dynamics and duration (all people left at the same time? They intend to come back? Were the same, their descendents or others that reoccupied the site? Etc.), and the reasons of reoccupation are central to understand the role of these sites in local and regional settlement networks and their historical circumstances throughout time. Abandonments are as important as occupations, just like what is missing is as important as what is present. 

References:

Silva, C.T & Soares, J. (1987), “O povoado fortificado calcolítico do Monte da Tumba I – escavações de 1982-86 (resultados preliminares)”, Setúbal Arqueológica, VIII, Setúbal, p.29-79.

Valera, António Carlos (2003), “Mobilidade estratégica e prolongamento simbólico: problemáticas do abandono no povoamento calcolítico do Ocidente Peninsular”, Era Arqueologia, 5, Lisboa, p.126-149. (http://www.academia.edu/attachments/2325706/download_file)

0103 - The importance of good geophysics

The importance of good geophysics is evident. It can provide a global image of a site (that we can only have by traditional archaeological excavation after at least some decades) allowing the development of the scientific inquiry and research, it is not intrusive, so it doesn’t rise the problems that an excavation does, and provides a powerful planning tool (in research or impact assessment contexts).

At Perdigões, the geophysics done by Helmut Becker (Márquez-Romero et al. 2011; Valera et al., in press) is important, not just for the general interpretation of the site, but because it allows the contextualization of the excavated areas in a broader picture. Now we know exactly where we are in the site. But also important, we can plan where we want to be.

And in this year campaign, this is one of the places we want to be: the area inside Late Neolithic Ditch 6, where the geophysics showed two tiny lines that might correspond to palisades.

Fragment of the geophysics of Perdigões with the location of the area to survey

Well, we prepared the excavation by removing the ploughed upper level, and there it was: Ditch 6 and inside two smaller parallel ditches corresponding to the geophysical image (with an extra: a small pit between Ditch 6 and the first inside line). The goals, now, are characterize these structures, try to determine their functionality and date them.

Survey area, confirming the presence of the structures.

References:

Márquez, J.E.; Valera, A.C.; Becker, H.; Jiménez, V. & Suárez, J. (2011), “El Complexo Arqueológico dos Perdigões (Reguengos de Monsaraz, Portugal). Prospecciones Geofísicas – Campaña 2008-09.” Trabajos de Prehistoria, Madrid.

Valera, A.C, Márquez, J.E., Becker, H., Jiménez, V. & Suárez, J. (in press B), “O Complexo Arqueológico dos Perdigões: nova imagem e novos problemas proporcionados pela prospecção geofísica” Actas do 8º Encontro de Arqueologia do Algarve, (2010), Silves.

0102 - List of Portuguese enclosures updated

Click to enlarge

Walled enclosures (red squares)

Ditched enclosures (yellow circles)

Walled and ditches enclosures (blue stars)

It will stay available in the page dedicated to maps.

0101 - Fonte Quente walled enclosure

Image of the wall structures on Fonte Quente (taken from Batata & Borges, 2011)

Location: Tomar municipality, Santarém district, Central Portugal)
Chronology: Chalcolithic

Bibliographic references: Oosterbeek, 1994; Batata & Borges, 2011.

Known since the early times of the XX century, and with several interventions along that century, the Fonte Seca site was recently submitted to a large area excavation, due to the construction of a highway (Batata & Borges, 2011). This last intervention revealed a large walled enclosure. According to the excavators, it is now one of the biggest of Central Portugal, with an estimated area around 20ha.

Three walls were detected, some with semi circular bastions. Metal artefacts and evidences of copper metallurgy were also recorded as well as beaker pottery and schist plaques with geometric decoration (typical of Alentejo region, but also present in the Tejo valley).

In an earlier survey (Oosterbeek, 1994) one radiocarbon date was associated to one of the walls: 3790+/-120BP. Calibrated at 2σ, and due to its large standard deviation, this date presents a huge interval between 2600 – 1850 cal BC, but that goes well with the later materials, like the beaker pottery.  

Bibliographic References

OOSTERBEEK, Luiz (1994) – Echoes from the east: the Western Network – North Ribatejo (Portugal): an insight to unequal and combined development, 7000 – 2000 B.C., University College London, Institute of Archaeology.

BATATA, C. & BORGES, N. (2011), “A importância da Fonte Quente enquanto “Lugar Central” no contexto do povoamento Pré-Histórico do Alto Ribatejo, durante a Pré-História Recente”, Resumo dos trabalhos de escavação arqueológica realizados no decorrer da empreitada do Sublanço do IC9 – Nó de Carregueiros / Tomar, E.P. Estradas de Portugal.

0100 - Going public

I talked about this before: the archaeology of prehistoric enclosures (as all archaeology actually) needs to go public. In fact, its relevance (and the relevance of its professionals) critically depends in the capacity of produce some valued social return, and there are some interesting projects all over Europe working this way.

In Portugal, we are just beginning, and Perdigões is a leading project on that matter, assuming that research has its own funding future and social justification in becoming relevant to the general public. But we are also aware that its relevance depends back in regular research of quality.

So, at Perdigões there is a path that is being walked with conviction in social responsibility. And that has been noticed here and there.

Even Google caught us excavating last year (2011). It was the first week of field work. And we will be there again this year. Next week we will be preparing the excavation that will start at July 16^th. You can fallow it then in its own blog (see the side bar).

0099 - Ditched enclosures in the Portuguese north hinterland

Ditched enclosures in central/north Portugal (Yellow circles). Santa Bárbara is number 30.

The actual distribution of ditched enclosures in Portugal shows a clear concentration in Alentejo region, in the Guadiana and Sado basins. But some enclosures with ditches also started to appear in the north part of the country. First in the littoral. But in the last years they were detected also in the hinterland, in Beira Interior.

Is the case of the ditched enclosure of Santa Bárbara, Sabugal (Peresterlo & Osório, 2005). Unfortunately there is not much information published about the site and its negative structures. Through some newspapers articles we know that there are pits and a ditch (25 meters long and 3 meters wide), apparently dating from the Chalcolithic.

The site is very near the Spanish border and that region of Portugal is part of the western traditional pathway between the two Iberian central Mesetas and a natural extension of the central territories, both north and south of the Central Mountain System. Well, in both areas, the Madrid region and the Douro valley, the last decades have revealed a significant density of ditched enclosures. Besides, the Beira Interior region is also well connected to the South, being part of that north-south route that links three mains river valleys: the Douro, the Tagus and the Guadiana.

It is a linking region, well marked in several historical periods (such as in the Bronze Age through stelae distribution), connected to areas where ditched enclosures are very well represented. So, it was just a matter of time before they started to appear here too. And more are expected for the near future.  

0098 - Dating ditch fillings

Dates from ditches 3 and 4 from Perdigões. They are Chalcolithic ditches, dated from the 2^nd quarter and middle 3th millennium BC. But in a top layer of ditch 4 we got a Late Neolithic date (a ditch that has to middle 3^rd millennium dates for bottom deposits). A typical situation of incorporation of earlier material. In fact, just 3 meters away there was a Late Neolithic pit burial that was disturbed in Chalcolithic times. Taken from Valera & Silva, 2011.

Dating the fillings of ditches and interpret the results is a tricky issue.

First, we must be aware that we never date the opening of a ditch, only the beginning of its filling. And we do not know the time between the opening and the beginning of the last filling process of the ditch (I say last because we must considerer the possibilities of re-openings).

Second, what is integrated in the ditch filling may be older than the filling process or even older than the excavation of the ditch. In fact, especially in sites with long living periods (like Perdigões, for instance), where earlier materials can be about or the excavation activity is so intense that earlier deposits are constantly being remobilized, it is natural that some of the material that integrates a filling deposit inside a ditch is actually from earlier occupations. By dating this material we will not date what we intent to. We will be dating earlier material that has nothing to do with the time the ditch building or its filling moments. That is why sometimes we have earlier dates in top deposits and later ones in the bottom deposits.

So, how can we avoid these problems?

Dating ditch fillings implies dating series of samples, where outliers can be detected. It is not just the need of dating the sequence of deposits to determine the filling rhythm (which is, of course, important). Even if there are just one or two deposits, we must have more than just one date, precisely because of the problems raised by the typical dynamics and activities that take place in this kind of sites.

It is more expensive, I know. But one date in a ditch, except if you have a well defined and closed context (like a burial, for instance), is far from enough. And every date or series of dates need a serious critique, regarding the dating procedures, dated material, relation to context, nature of the context formation, post depositional events, and so on. Or we will just adding smoke to an already foggy area.

Bibliographic References:

Valera, A. C. & Silva, A. M. (2011), “Datações de radiocarbono para os Perdigões (1): contextos com restos humanos nos Sectores I e Q”, Apontamentos de Arqueologia e Património, 7, Lisboa, NIA-ERA, p.7-14.

0097 - How did they do it?

They did choose adequate bedrocks. There is a clear relation between Portuguese ditched enclosures and geology that enables an easier excavation. But making it easier doesn’t mean it was easy.

In fact, to excavate the ditches, that in South Portugal started at least in Late Neolithic (second half of the 4th millennium), they must have used the technology developed since earlier times: the technology developed in mining for flint or for minerals, like variscite.

I have already drawn the attention for the fact that there are several evidences of “transference of technology” in Prehistory, from some areas to others; from some kind of architectures to others. For instance, the building of the access corridor between walls to the inside enclosure of Castro de Santiago is clearly an application of megalithic building procedures.

So, to study the technologies adopted to open ditches it is in mining tools and in mining techniques that we might find a window. There is a clear interesting relation that can be established between the researches of these two Neolithic practices.

And the same can be argued about the hypogeal building tradition. There is knowledge and an assemblage of techniques and tools that must have had a transversal use in different building activities. Underground techniques of excavation are certainly earlier than ditched enclosures in western Iberia. They might have provided the means to the architectural materialization of some new ideas. Just like the megalithic “engineering” was certainly helpful for walled enclosures.

So, looking into mines, and mining material, might be useful when we study ditched enclosures.

0096 - The sunset of ditched enclosures?

Small inside enclosure with a burial pit.

When did the Neolithic and Chalcolithic type of ditched enclosures stop being built? Well, as the question suggests, it would have been at the end of the Chalcolithic, of course. In fact, at the present moment, no ditched enclosures like those are known to have been built in the second millennium BC. I recently have used this apparent situation to argue that the Neolithic and Chalcolithic ditched enclosures were related to a specific ideology (or cosmogony) and that they stopped being built in the beginning of the second millennium precisely because that cosmogony was structurally changing at the end of the third millennia (Valera, in press).

Well, the enclosure in excavation by ERA at the moment seams to reveal a relative late chronology, although every elements of the architecture also seems to be rooted in the Neolithic tradition. It is soon to be conclusive. But the pottery from the ditches suggests a late chronology in the third millennium and there are pits with pottery that clearly indicate the first half of the second millennium (Bronze Age).

The image, at the moment, is that the enclosures were built in a late Chalcolithic and that pits were still being excavated in the early Bronze Age. But the relations are still to be established. In fact, the inside ditch, the one that slides deeper from the gate to de back, is very small (just 8 m diameter inside) and has only one pit inside. Well that pit has an individual burial with three complete undecorated vessels and a Palmela point, indicating a moment of transition to Bronze Age. Is it a latter pit? Or this small enclosure was built to enclose that pit?

Detail of the burial excavation in a earlier stage. We can see the leg and the skull (and a stone over the neck).

It is soon to decide. But what this data is suggesting is that some of this Neolithic rooted architecture and practices might have reached the beginning of Bronze Age. In a way not yet recorded.

That does not question yet the idea that those architectures are essentially related to a Neolithic cosmogony. Structural transitions are just like that, presenting punctual and exceptional late extensions. So let’s see what the absolute chronology says.

One thing is already certain: this site is important to the problematics regarding Portuguese ditched enclosures.     

Refrences:

Valera, A.C (in press) “Mind the gap: Neolithic and Chalcolithic enclosures of South Portugal” (A. Gibson & J. Leary, eds), ENCLOSING THE NEOLITHIC: RECENT STUDIES IN BRITAIN AND EUROPE, BAR.