Megaliths and Neolithic astronomy in southern Egypt

J. McKim Malville¹, Fred Wendorf², Ali A Mazar³ & Romauld Schild⁴

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Abstract

The Sahara west of the Nile in southern Egypt was hyperarid and unoccupied during most of the Late Pleistocene epoch. About 11,000 years ago¹ the summer monsoons of central Africa moved into Egypt, and temporary lakes or playas were formed. The Nabta Playa depression, which is one of the largest in southern Egypt, is a kidney-shaped basin of roughly 10 km by 7 km in area^{2, 3, 4}. We report the discovery of megalithic alignments and stone circles next to locations of Middle and Late Neolithic communities at Nabta, which suggest the early development of a complex society. The southward shift of the monsoons in the Late Neolithic age rendered the area once again hyperarid and uninhabitable some 4,800 radiocarbon years before the present (years bp). This well-determined date establishes that the ceremonial complex of Nabta, which has alignments to cardinal and solstitial directions, was a very early megalithic expression of ideology and astronomy. Five megalithic alignments within the playa deposits radiate outwards from megalithic structures, which may have been funerary structures. The organization of the megaliths suggests a symbolic geometry that integrated death, water, and the Sun. An exodus from the Nubian Desert at ～4,800 years bp may have stimulated social differentiation and cultural complexity in predynastic Upper Egypt.

Pastoralists seem to have entered the Nabta region (Fig. 1 inset) during the summer rainy season beginning ～10,000 years bp. Most of the early sites at Nabta consist of small concentrations of artefacts with one or more hearths, evidence of repeated summer occupation by small family groups. In addition to bones of gazelles, hares, jackals, and small mammals, most of the sites also contain bones of cattle, which may have been used for milk, blood, and transport⁵,⁶.

Figure 1: A plan of the stone structures found in the western portion of the Nabta Playa (scale in metres).

A map of Egypt, giving the location of the Nabta Playa, is shown as an inset. True geographic north is indicated. A indicates the largest megalithic structure; E is a smaller megalithic structure. High resolution image and legend (41K)

There were three major moist periods in the Holocene epoch in the Eastern Sahara, each of which is documented by massive silt deposits in the seasonal playas, for which we have over 100 radiocarbon dates⁷. These three playa episodes of the Early, Middle, and Late Neolithic ages were separated from each other by periods of hyperaridity, at 7,300–7,100 years bp and 6,700–6,500 years bp, when the water table was lowered to the same or lower levels than those of today. The preceding playa silts were extensively eroded and in some instances sand dunes filled the hollows. The alignments, megalithic structures and sandstone circles were placed in sediments that probably accumulated between 7,000 and 6,700 years bp, at the end of the Middle Neolithic.

These Neolithic settlements reveal repeated occupation over several millennia during the summer rainy season, when there was enough water in the playas for large groups and their animals. At 8,100–8,000 years bp in the Early Neolithic, dates that are well established by a cluster of radiocarbon dates from charcoal and ostrich eggshells, larger communities appeared. One village (E-75-6) contained more than 18 houses, arranged in two (possibly three) straight lines, and deep walk-in wells, which required significant labour investment and control³,⁸. One well that we excavated was 4 m in width and 3 m deep; the existence of this well may have made it possible for some people to live in the desert throughout the year. The construction of the wells may be the first indication of emerging social control that later made the design and execution of the megalithic complex of the Late Neolithic possible.

Although primarily attracted to the playa for its water and forage, these nomadic groups must have engaged in a variety of activities during summer occupation, such as social bonding, marriage, trade,and ritual. The abundance of cattle remains in the Middle and Late Neolithic settlements is consistent with the ritual traditions of modern pastoralists, who may slaughter cattle to mark socially important events. We excavated two types of cattle tumuli at Nabta. The most common type consists of unshaped blocks of sandstone containing disarticulated bones of one or more cattle.One such tumulus (E-96-1) has yielded a date of 5,500 years bp ±160 years, from charcoal in a hearth. The second type of cattle tumulus (E-94-1), which may have marked a place and an event of considerable ideological significance for the group, consisted of an articulated skeleton of a young cow buried in a roofed, clay-lined chamber, which was covered with unshaped sandstone blocks. Wood from the roof of the chamber yielded a radiocarbon date of 6,470 ±270 years bp.

Oval clusters of large recumbent slabs constitute the megalithic structures (Fig. 1), which we initially thought might mark high-status burials. However, no firm evidence of human burials was found in any of these features. Although churning clay vertisol would probably have destroyed all buried material except large rocks, the structures may have served primarily as proxy tombs for high-ranking individuals who died on the trail. Excavation and drilling of five of the structures showed that each one was built over a modified table rock, which perhaps functioned symbolically as a cenotaph. We obtained a radiocarbon date of 4,800 years bp± 80 from one of the smaller structures (E-96-1; structure E).

Beneath the surface slabs of the largest megalithic structure (E-96-1; structure A) we found a sculptured rock, which has some resemblance to a cow. It was standing upright with its base 2 m below the surface, and its long axis was oriented a few degrees west of north. The rock had been blocked into place by two smaller slabs. Further beneath it, at a depth of 4 m, the shaped table rock had a similar northward orientation.

Excavations of the megaliths contained in the alignments reveal that they are not bedrock material. These slabs, typically measuring 2 m by 3 m, were brought from exposed sandstone, over distances of 0.5 km or more, and then embedded during the Late Neolithic in playa deposits. Megalith 0, with an exposed length of 1.5 m, is shown in Fig. 2 and is the northernmost stone of alignment II. Numerous deflated hearths and Late Neolithic pottery⁹, all of which appear to be contemporaneous with the megalithic alignments, surround the megaliths and cattle tumuli.

Figure 2: Megalith 0, the northernmost stone of alignment II (Fig. 1).

High resolution image and legend (501K)

The longest series of standing megaliths (megalithic alignments I, II and III; Fig. 1) was originally interpreted² as a single line of megaliths orientated approximately 10° east of north. Our re-evaluation of the alignment indicates that the slabs are organized into three separate lines, which radiate outwards from the largest of the megalithic structures, E-96-1 structure A, with azimuths of 24.3°, 25°, and 28°. During the 1997 season, we combined theodolite and differential global positioning system measurements to map the megaliths, and established the centre of structure A at 22° 30' 29.7" N, 30° 43' 31.2" E. We discovered two additional megalithic alignments, which also radiate out from the vicinity of structure A, with azimuths of 90.02° and 126°. We have not excavated the bases of these megaliths, but they appear to be similarly embedded in playa deposits.

The circle (E-92-9) of small upright and recumbent slabs, with a diameter slightly less than 4 m (Fig. 3a–c), contains four sets of upright slabs, which may have been used for sighting along the horizon. The circle is too small to have functioned as a precise sighting device. The centre lines of the two windows have azimuths of 358° and 62°. Taking into account refraction, we estimate the azimuth of the first gleam of the summer solstice Sun 6,000 years before the present to have been 63.2°, which would have been visible through the slots of the circle. The location on the horizon of the rising Sun close to the summer solstice may have acquired additional significance because of Nabta's proximity to the Tropic of Cancer. At this latitude, the Sun crosses the zenith on two days, approximately three weeks before and after the summer solstice. Vertical structures cast no shadows under the zenith Sun, and within the tropics the day of the zenith Sun is often regarded as a significant event¹⁰.

Figure 3: Stone circle and monolith.

a, b, Stone circle, E-92-9. b, The outer eight standing stones that establish sighting slots, in addition to the mix interior standing stones, are shown in black. Recumbent stones are shown in white. c, Southwest window of circle in a, b. d, Standing monolith (height 1 m). High resolution image and legend (200K)

In addition to the north–south sight-line in the calendar circle, other suggestions of the importance of cardinality are provided by the east–west megalith alignment that extends from structure A and the isolated monolith (Fig. 3d), which lies 1.8° east of north from megalithic structure A. The exposed and buried slabs of structure A, as well as many of the exposed slabs in the other megalithic structures, were also aligned with their long sides approximately north–south.

Although no star was visible at the north celestial pole during most of the occupation of Nabta, north directionality would have been important for nomadic groups navigating across the Sahara. The standing megaliths would have been apt devices to acknowledge the zenith Sun near the onset of the rainy season. Placed in playa deposits, the megaliths would have been partly submerged in the rising waters of the summer monsoon, and they may have been considered to be ritual markers of the onset of the rainy season. The megalithic complex may have been an expression of interconnections between the Sun, water, death, and the fertile Earth. The unusual standing monolith, either chosen for its shape or intentionally sculptured, is a suggestive symbol of male fertility.

The symbolic richness and spatial awareness seen in the Nabta complex of the Late Neolithic age may have developed from adaptation by nomadic peoples to the stress of survival in the desert. The ceremonial complex could not be more recent than the onset of hyperaridity in the region around 4,800 years bp, suggesting that the astronomy and ceremonialism of Nabta occurred before most of the megalithic features of Europe, Great Britain, and Brittany were established. Within some 500 years after the exodus from Nabta, the step pyramid at Saqqara was constructed, indicating that there was a pre-existing cultural base, which may have originated in the desert of Upper Egypt. An exodus from the Nubian desert at ～5,000 years bp could have precipitated the development of social differentiation in predynastic cultures through the arrival in the Nile valley of nomadic groups who were better organized and possessed a more complex cosmology.