(ORDO NEWS) — Dolmen Menga is a megalithic mound called tumulus, a long mound, a kind of dolmen. It is located near Antequera, Malaga, Spain.
It is one of the largest known ancient megalithic structures in Europe. It is 27.5 meters (90 feet) long, 6 meters (20 feet) wide, 3.5 meters (11 feet) high, and was built from thirty-two megaliths, the largest weighing about 180 tons (200 tons).
A very rare feature of megalithic structures is the presence of a deep and narrow well at the bottom of the chamber. It represents a series of anthropomorphic engravings in the form of a cross, as well as a star, in the first orthostat of the corridor.
The megalithic complex of Antequera includes the dolmens of Menga and Viera, as well as the tholos El Romeral. Standing out among these three sites, Menga can be considered one of the most significant manifestations of the megalithic phenomenon in the world, with a long history of study.
However, despite this long history of research, the architectural design of the Meng dolmen has never been studied from a broad engineering perspective, analyzing its building materials, dimensions, and geometry.
The present study follows this approach, building on a systematic geoarchaeological, archaeometric and statistical analysis, which, as discussed below, provides the basis for a new understanding of this unusual megalithic site.
The Meng dolmen is located on top of the detrital sedimentary materials of the upper torton, with an abundance of sands, some of which are lightly cemented, mostly uniform in size and subcircular.
The same materials contain polygenetic and heterogenetic pebbles of various thicknesses, as well as several rather large blocks.
In addition, there are layers of low-energy shales. These sequences arose as a result of dike processes in channels with erosion bases and updrafts, many of which are imbricated, which is typical for deltaic facies.
The Menga dolmen is located next to the Viera dolmen on top of a low hill on the northeastern outskirts of Antequera. The entrance to the monument is oriented to the northeast, offering a panoramic view of a large area, including the Peña de los Enamorados mountain and the vast area of the Antequera basin.
The area around the Antequera megalithic complex is exceptionally rich in both biotic and abiotic resources. As a mineral resource, flint was of particular importance in the construction of the Antequera megaliths during the Neolithic and Copper Ages.
The clastic rocks used for the construction of the Menga dolmen and two other megaliths of Antequera were brought to a distance of no more than 500 m from the construction site of the Antequera dolmens.
The Menga dolmen has been classified as a gallery dolmen because it has no internal structure. Menga is considered to be a single-opening megalithic structure, although the chamber has a thin, narrow, transitional space leading into the chamber, a sort of pseudo-passage or antechamber.
The chamber is lined with fourteen orthostats (seven on each side) and only one filling stone, which together form a large space 16.5 m long and 6 m wide at maximum width. The roof is formed by five stones supported by the aforementioned orthostats and three large pillars aligned with the axis of the chamber.
The vestibule chamber has two walls with three orthostats on each side and one capital, which today has no supporting pillar. The results of the latest excavations carried out inside the dolmen, show the possible existence of one or even several orthostats in the atrium and one additional pillar.
This pillar had to be in line with the above and located between the back of the chamber and the front of the antechamber.
Traditionally, the Antequera megalithic complex has been dated by indirect analysis of the cultural context as part of the megalithic phenomena in the south of the Iberian Peninsula during the 5th millennium BC.
The Menga dolmen is considered to be the oldest dolmen in the Antequera megalithic complex, since there is no clear distinction between the chamber and the corridor.
Recent excavations carried out by the Regional Council for Culture of the Government of Andalusia have made it possible for the first time to date the Antequera megalithic complex in absolute terms.
The first dating of the complex corresponds to a fragment of vegetable coal located at the bottom of the barrow from the Viera dolmen. Therefore, having received the result of 4550±140 years cal. BP, this date is interpreted to correspond at least with the start of construction of the tumulus.
During the excavations of the Menga dolmen in 2005-2006, three more samples of vegetable coal were found: two of the two pits located in the atrium, and one more from the base of the tumulus.
These three samples date back to the 6th millennium cal. BP, and thus the construction of the dolmen corresponds at least already to the Late Neolithic.
However, all specimens were found in the geological substratum under the dolmens, not inside them, which points to the terminus post quem, that is, the earliest date when the construction of dolmens could begin.
The present study of Meng aims to explain his geometric design through analysis of the lithology, volumes, dimensions, and weights of his orthostats. The analysis is broken down into three specific levels: materials, geometry, and orientation.
The megalithic structure of the Menga Dolmen has unique architectural characteristics in terms of its size, weight, volume and lithology, making it one of the most important civil engineering and architectural works of the European prehistory.
However, this monumentality was designed using irregular geometry, reflected in the weight, length, volume and lithology used on both sides of the longitudinal axis that divides the dolmen into two halves from the entrance to the back.
The left side of the chamber can be considered homogeneous in all these characteristics, but the right side is not. Moreover, the geometric accuracy on the left side is higher than on the right side: the former almost perfectly matches the polynomial curve of the third degree.
This is no coincidence, since during the construction of the dolmen, cultural factors influenced the design and led to such a contrast in the accuracy between the linear geometry of the left side and the fractality of the right side.
This cultural factor can be found not only in the Menga dolmen, but also in the other aforementioned large dolmens in the south of the Iberian Peninsula, such as Pozuelo 4, Alberite and Soto, all of which have similar geometric patterns.
Pozuelo is precisely oriented to the summer solstice, while Alberit and Soto are precisely oriented to the equinox. However, the Menga dolmen is slightly offset in relation to the summer solstice.
The location of the Menga dolmen can be explained both by its orientation towards Peña de los Enamorados and by its orientation towards sunrise at the summer solstice, as evidenced by the intentionality of the shadows formed on the left side.
The absence of dark orthostats in the Menga dolmen demonstrates a complete knowledge of the annual cycle of the sun and a deep symbolic meaning of lighting the camera at sunrise during the summer solstice.
These patterns, repeated in the four considered dolmens, show that both the geometry of the dolmens and their orientation can be explained by a common cultural factor, in which the imperfect right side is associated with uneven refraction of light, and the exact left side is associated with an even distribution of darkness.
The Menga Dolmen is a colossal megalithic structure in which a large artificial mound with a diameter of about 50 m combines and covers 24 orthostats, five covers and three support pillars, which form an interior space of a covered length of 21.5 m and a minimum height of 2.66 m.
In addition Rather than collecting all of these elements in as much detail as possible, the 2005 study also had as a priority to integrate the newly discovered well at the bottom of the chamber (an architectural element hitherto unknown and never mapped) into the overall planimetry.
In addition, Meng’s detailed planimetry was integrated into the overall cartography of the entire surrounding protected area.
To develop this work, the following activities were carried out:
a. Aerial photogrammetry at a scale of 1: 3000 based on color images, classical topographic survey and GPS as the cartographic basis of Menga and the entire Corps 1.
b. Laser scanning of Meng to obtain a complete surface topography of the architectural elements that make up this monument.
c. Integration of laser scanning and digital imaging.
When the work described here was carried out in 2005, it was a groundbreaking implementation that became the first 3D model of a megalith in the Iberian Peninsula. In subsequent work, the laser scanning methodology was applied to other Iberian archaeological sites and monuments, in particular to caves, shelters, megaliths and stelae.
The combination of photogrammetry and a terrestrial laser scanner is currently a well-established technical solution for the registration of architectural elements and archaeological sites.
The results achieved were very satisfactory due to the integration of digital image based photogrammetry solutions and short range laser scanning.
The cartographic and infographic database of Meng that was received then constituted and constitutes today a fundamental tool in the management of CADA, a tool to overcome a serious shortcoming that arose in 2004, when the current stage of his management began.
This cartographic basis was used to create a unified and detailed digital planimetry of the exposed networks and key archaeological features found during excavations in 1980-1990 and later in 2005-2006.
This documentation is of great importance for planning further work on this site, as well as for the scientific analysis of its complex biography.
At the archaeological level, an example of using the high-resolution planimetric survey of the Menga dolmen described in this paper is the calculation of its axial orientation, which made it possible to more accurately and precisely study its landscape relationships with La Peña de los Enamorados.
This calculation, or the investigations subsequently begun at Piedras Blancas I, on the northern slope of Peña, would not have been possible without the precise mapping already described.
Another example is Meng’s geoarchaeological survey, for which laser scanning was used as a cartographic basis, including calculating the volume and weight of each orthostat, cover, and support over its surface area. Finally, laser scanning also served to simulate solar illumination inside the dolmen,
Both for planning the management of this great megalith for its protection and conservation, and for exploring its landscape and social dimension, therefore, high-resolution planimetry of the Menga dolmen using terrestrial laser scanning, 3D surveying and photogrammetry is a resource of great importance and efficiency.
Perhaps the most unexpected and surprising find during the excavations at Menge in the spring of 2005 was a water well found at the bottom of the megalithic chamber. At the time when this sensational discovery was made, there was no record of the existence of this element, no previous mention of it was known.
The Menga Well has already been the subject of some studies and publications, including faunal remains found during the 2005 and 2005-2006 campaigns, a full chronometric assessment of its refilling based on radiocarbon dating of animal bones, and the physicochemical characterization of its water.
However, as explained in this chapter, there are many important aspects of this exceptional hydraulic structure that have not yet been studied by science.
The well is located 0.80 m from the rear (western) edge of Pillar 3 (P-3) of Menga, 2.3 m from the head orthostat (0-12) and 2 m from orthostats 10 and 14. Although at the mouth it has round shape, at its base the walls are slightly bent inward, so its section describes a U-shape.
In fact, its diameter, which is 1.60 m at the mouth, decreases to 1.10 m at the base. Up to a depth of 13 m, the well section is almost straight, therefore geometrically it has the shape of a cylinder, but further the diameter narrows and takes on the geometry of a truncated hole. In total, the depth of the well is 19.40 m and the volume is 35.36 m³ (35,360 l).
From a formal point of view, the walls of the Menga well have a very regular finish, with a uniform surface, on which only 77 mechinals stand out, which should have been used during its excavation and possibly in subsequent maintenance tasks.
Throughout the development of the well, traces of work were found on the walls. It is impossible to determine whether these traces were made with stone, horn or metal tools using a purely macroscopic assessment, so these signs have not yet been used to more accurately assess the chronology of the discovery of this element.
Of course, future comparative analysis based on experimental testing using different types of tools on the same rock in which the well was discovered may help shed light on its age.
It can be said that the Menga well was dug out of relatively soft rock, which undoubtedly contributed to its exceptionally regular and symmetrical shape.
A recent chemical analysis has shown the good quality of the Menga Well water as virtually all physico-chemical parameters are within the levels required for water fit for human consumption under current legislation. The chemical analysis of the water from the well shows a strong similarity with the groundwater characteristics of the Antequera Plain.
In this regard, it is extremely interesting that at about 200 meters above sea level Menga at an altitude of 474 meters above sea level, for which there is information on the water table indicating that the depth of the water layer is only three meters, and even a little further north, the terrain cuts off the water table, which might lead us to believe that there may have been upwelling in this area in the past.
This conclusion raises a very simple question, but one of great logical importance for understanding the significance of the Meng Well: if the function of the Meng Well was purely utilitarian (providing water for human or animal consumption), why did its builders decide to drill almost 20 m of detrital rock when at a distance 200 m they had the opportunity to access water at a depth of three meters?
The topographic and hydrogeological location of the well suggests that those who built it took the trouble to drill 20 m of calcarenite rock to reach the aquifer, because they specifically wanted the well to be inside a dolmen.
From a microspatial point of view, the location of the well in Menge, just behind pillar 3 and perfectly centered with respect to the side orthostats and the head orthostat, suggests that those who created it wanted it to be in the central place of the monument and in harmony with the surrounding space.
The morphology of the Menga well has characteristics that distinguish it from wells designed exclusively for water supply: the fine finish of its walls and the perfect roundness of its installation in almost all of its development suggest that special care has been invested in its manufacture in order for the well to produce a specific aesthetic and visual Effect.
A priority in the study of the Meng Well is the analysis of stone marks on its walls, as this can help determine the type of technology and tools used in its manufacture, which will give clues to the age of its construction.
The drawings at Menge, which are apparently poorly preserved, were almost completely erased when the site was cleared for the last time. From the point of view of the study of rituals, the demonstration of several operations on stones is extremely important information that allows us to interpret the “biography” of the monuments.
The megaliths we see today are the end result of a sequence of transformations, maintenance and restoration.
Interpretations, which have a verifiable basis in the protocol for the analysis of jewelry on monuments, have made it possible to obtain data that until recently would have been unthinkable for this kind of assessment.
This dynamic hypothesis of relatively large structures is beginning to define reference points in a large proportion of the structures that have been studied in depth. This refers to the dolmens of Antekeran.
Although the graphic documentation is not yet fully completed, the evidence obtained at Menge and Viere showed that the reuse of the oldest stones played a large role in their designs. We also suspect that the stones were reused at Romeral, as indicated by the menhir fragments cited in other studies.
Likewise, the stone preparation system at both sites and the decorative application link the two structures very closely, and this suggests a possible source of the large stelae that were used to create the Mengi and Viera dolmens as we see them today.
It is possible that Menga had a carved door in its outer access, which was rebuilt at some time during its use. Indeed, the position of this stone coincides with the position of a possible threshold.
Engravings are found on some stones in Menge, especially on pillars 1 and 2. These are narrower and rounder landforms.
They usually form geometric motifs arranged in rows, including wavy lines and zigzags. Their sides and tops show uneven cuts on the surface that was formed earlier, and this creates a very bright jagged profile. Of particular interest is the smoothing of relief areas, which created a special quality of relief surfaces.
At Menge, some evidence indicates that large stelae were incorporated into the monument. Possibly this refers to the Orthostat 10 cut through at the top right by several sharp blows that bring out the semi-circular head through the resulting volumes.
However, the clearest work is seen in the tombstone, which has been noticeably undercut and smoothed out on the left side. The original stela has been laid on its side with its apex toward orthostat 11, and three-quarters of it is visible. Another part of it is fragmented or was installed in the hole where the tombstone was placed.
The tombstones at Menge show lime, as well as some traces of red paint.
Documentation already published on Meng’s chamber lid correlates the engraving technique used with that seen in the Vier Pass. The current state of the stone makes it impossible to determine whether it has been redecorated; although the whiteness of the lime is visible, this has not yet been confirmed analytically.
Photographs taken during the archaeological documentation by Meng’s team allow the reconstruction of its external form with a central ledge, as well as the careful elaboration of its outline, which is clearly trapezoidal.
Other stones in Menge are remarkably similar in their shape and preparation.
It is likely that the trapezoidal stones in the Menga dolmen, worked all around and showing clear signs of reproduction of anthropomorphic figures, are stones that were previously used.
The trapezoidal shape of these stelae means that they may have been cut into three pieces, which seems to be the most common layout of some of the pilasters at Menge. The pillars may have been made from the remaining thirds.
Basic examination of stone thickness is difficult without more accurate measurements of the invisible sides of each orthostat and top stone. However, the thickness of the stones at the entrance to Menge is the same as that of the pillars, especially at 1 and 2.
Decoration in the form of black and red stripes over a white layer that covered an older decoration, of red triangles and a relief of red, appears in Menge, where orthostat 11 and pillar 1 are prominent examples, showing that the superimposition of triangle patterns on stripes occurred in a large monument.
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