Visualizzazioni totali

mercoledì 27 giugno 2012

Singa the middle of FUNJ SINNAR state of Funj.

Singa Hominid Skull: The Singa (Sudan) calvaria has been interpreted previously as a terminal Pleistocene modern human fossil, perhaps related to the Bushman of Southern Africa. Here we report new mass-spectrometric U–Th dates for the calcrete deposit enclosing the fossil teeth and the calvaria itself and new electron spin resonance (ESR) dates for associated dental materials. The new data constrain the age of the hominid to at least 133 & 2 ka. Together with the preferred linear uptake (LU) ESR dates, the U–Th data confirm that the intriguing mixture of modern and archaic characteristics in the Singa specimen date from isotope stage 6. Far from being a modern human fossil, it represents a rare example of an archaic African population which may have been ancestral to all modern Homo sapiens. Morphological and genetic evidence suggest that Homo sapiens originated in Africa some200–130 ka ago, but these critically important African populations remain poorly known and dated. A well-preserved hominid fossil from Singa, Sudan, previously supposed to represent a modern specimen (Rightmire, 1984; Clark, 1988) may represent such a population. The Singa fossil was discovered in 1924 by Bond, eroding out of a calcrete deposit in the west bank of the Blue Nile, some 320 km south east of Khartoum. Mammalian fauna and Palaeolithic artefacts collected from the locality and from Abu Hugar, some 15 km to the south yielded extinct, possibly Upper Pleistocene fauna (Bate, 1951). Prior to 1990, a radiocarbon date of ca. 17 ka on a crocodile tooth from Abu Hugar was the only absolute date available. Thus, the Singa hominid was regarded as ‘‘proto-Bushman’’ by Woodward (1938), and since then it has been attributed to modern H. sapiens. However, a have emphasized its archaic morphological and metrical features, and further study has supported Brothwell’s view that the unusual shape of the parietals might be related to pathology (Stringer et al., 1985). Preliminary electron spin resonance (ESR) dates on an associated Equus and bovid tooth from the Singa site (Grün & Stringer, 1991) had suggested an oxygen isotope stage 5–6 age, but these dates remained equivocal due to large discrepancies between early (EU) and linear (LU) uranium uptake models, and the uncertain contemporaneity of the dated teeth and the calvaria. Here we present new mass-spectrometric U–Th dates for the calcrete matrix found adhering to the external surface of the calvaria and enclosing associated mammal teeth. Unlike dental materials (e.g. enamel, dentine) which acquire uranium subsequent to burial, calcretes incorporate uranium into the calcite lattice at the time of deposition, thereby eliminating a major source of uncertainty which hinders U–Th and ESR dating of fossil teeth. Calcrete deposition clearly post-dated the burial of the fossil material and deposition may have continued over a period of time, implying that the U–Th dates reported here are minimum estimates for the age of the Singa hominid. Cemetery 117 at Jebel Sahaba: see attached photo above Cemetery 117 (also Site 117) is an ancient cemetery discovered in 1964 by a team led by Fred Wendorf near the northern border of Sudan. The remains discovered there were determined to be around 13,140 to 14,340 years old. The original project that discovered the cemetery was the UNESCO High Dam Salvage Project. This project was a direct response to the raising of the Aswan Dam which stood to destroy or damage many sites along its path. It is often cited as the oldest known evidence of warfare. The site comprises three cemeteries, two of which are called Jebel Sahaba, one on either side of the Nile river and the third cemetery being called Tushka. 59 bodies were recovered at Cemetery 117, as well as numerous other fragmented remains. There were twenty-four females and nineteen males over nineteen years of age, as well as thirteen children ranging in age from infancy to fifteen years old. Three additional bodies were also discovered, but their age and sex could not be determined due to damage and missing pieces. The skeletons were dated using radiocarbon dating and were found to have been approximately 13,740 years old. Of the people buried in Jebel Sahaba, about forty percent died of violent wounds. Pointed stone projectiles were found in their bodies at places that suggest the bodies had been attacked by spears or arrows. The wounds were located around the sternum, abdomen, back, and skull (through the lower jaw or neck). The lack of bony calluses, a natural result of healing around these types of wounds, indicates that the attacks were most likely fatal. The bodies and any other artifacts recovered by the UNESCO High Dam Salvage Project were recently donated by Fred Wendorf to the British Museum. This collection includes skeletal and fauna remains, lithics, pottery, and environmental samples as well as the full archive of Wendorf's notes, slides, and other material during the dig. North and South: Changing climates and environments Across Africa the Early Holocene wetter phase brought on much more favourable conditions within the Saharan region following its hyperarid phase. Higher rainfall brought high lake levels in Ethiopia and Chad, probably reaching their maximum extent around 8–9000 years ago. Lake Chad itself was greatly enlarged covering a massive area of some c.350,000km2. Within the Middle Nile, high flood levels have been identified along the White Nile (Adamson et al. 1982) with wide areas flooded during the annual floods and extensive swamps and lakes remaining after the flood receded. The clay plains of the Gezira region also saw a number of braided river channels running west of the present course of the Blue Nile (Adamson 1982). Areas susceptible to high and erratic flooding are unlikely to have been attractive to settlement. The northward shift in the monsoon belt and movement of vegetation zones which came in its wake provided the circumstances for a re-colonization of the once arid southern Sahara by populations from the south. The archaeological evidence for this will be explored in the next section. By the mid-Holocene however, conditions were becoming drier with the gradual southward shift in rainfall belts. Within this process there have been many fluctuations and as more well-dated environmental data are being accumulated, more detailed environmental reconstructions are becoming possible. Such environmental changes can also be tracked in the archaeological record. Large suites of radio- carbon dates now allow us to trace changing patterns of occupation in the deserts west of the Nile (Kuper 1989) and their ultimate abandonment. Much work has been concentrated in the western deserts of Egypt and much has been made of the possible consequences of such environmental changes on the Egyptian Lower Nile and ultimately for the ‘origins of the Egyptian civilization’. While often prominent in the literature, what was happening so far north is perhaps of rather peripheral importance to our main area of study. Instead we need to look much further south, to central Sudan. General References: • Arkell. A. J. 1961 The History of the Sudan. From the Earliest Times to 1821 (2nd edn) London: Athlone Press. • Arkell, A. J., Bate, D. M. A., Wells, L. H. & Lacaille, A. D. (1951). Fossil Mammals of Africa Vol. 2, pp. 1–50. London: British Museum Natural History. • Clark, J. D. (1988). The Middle Stone Age of East Africa and the beginnings of regional identity. J. World Pre-Hist 2, 235–305. • Wendorf, F. (ed.) (1968) The Prehistory of Nubia. 2 vols, Taos: SMU Press. • Woodward, A. S. (1938). A fossil skull of an ancestral Bushman from the Anglo-Egyptian Sudan. Antiquity 12, 193–195.

1 commento:

  1. Is this an image of the Singa fossils?
    I thought only a skullcap was found.

    Dirk Drubbel
    dirk.drubbel@gmail.com

    RispondiElimina