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THE SAHARA

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« on: August 10, 2008, 08:02:26 am »










                                                                   The Sahara

 




The Sahara is the world's second largest desert (second to Antarctica), over 9,000,000 km² (3,500,000 mi²), located in northern Africa and is 2.5 million years old. The entire land area of the United States of America would fit inside it. Its name, Sahara, is an English pronuciation of the word for desert in Arabic.

 
The boundaries of the Sahara are the Atlantic Ocean on the west, the Atlas Mountains and the Mediterranean Sea on the north, the Red Sea and Egypt on the east, and the Sudan and the valley of the River Niger on the south. The Sahara is divided into western Sahara, the central Ahaggar Mountains, the Tibesti massif, the Aïr Mountains (a region of desert mountains and high plateaus), Tenere desert and the Libyan desert (the most arid region). The highest peak in the Sahara is Emi Koussi (3415 m) in the Tibesti Mountains in northern Chad.

The Sahara divides the continent into North and Sub-Saharan Africa. The southern border of the Sahara is marked by a band of semiarid savanna called the Sahel; south of the Sahel lies the lusher Sudan.

Humans have lived on the edge of the desert for almost 500,000 years. During the last ice age, the Sahara was a much wetter place, much like East Africa, than it is today. Over 30,000 petroglyphs of river animals such as crocodiles survive in total with half found in the Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs have also been found here. The modern Sahara, though, is generally devoid of vegetation, except in the Nile Valley and at a few oases and in some scattered mountains and has been this way since about 3000 BC.

2.5 million people live in the Sahara, most of these in Mauritania, Morocco and Algeria. Dominant groups of people are the Tuareg-Berber, the Sahrawis, Moors, and different black African ethnicities including the Tubu, the Nubians, the Zaghawas and the Kanuri. The largest city is Nouakchott, Mauritania's capital. Other important cities are Tamanrasset, Algeria; Timbuktu, Mali; Agadez, Niger; Ghat, Libya; and Faya, Chad.

By 2500 BC the Sahara was as dry as it is today and it became a largely impenetrable barrier to humans, with only scattered settlements around the oases, but little trade or commerce through the desert. The one major exception was the Nile Valley. This well watered section of the desert became one of the most densely populated regions on the planet and the home to one of humanity's earliest civilizations. The Nile, however, was impassable at several cataracts making trade and contact difficult. Over time Egypt spread south and technologies such as iron working, and perhaps ideas such as that of monarchy spread into Nubia and further south.

Sometime between 633 and 530 BC Hanno the Navigator either established or reinforced Phoenician colonies in the Western Sahara, but all ancient remains have vanished with virtually no trace

By 500 BC a new influence arrived in the form of the Greeks and Phoenicians. Greek traders spread along the eastern coast of the desert, establishing trading colonies along the Red Sea coast. The Carthaginians explored the Atlantic coast of the desert. The turbulence of the waters and the lack of markets never led to an extensive presence further south than modern Morocco. Centralized states thus surrounded the desert on the north and east; it remained outside of the control of these states. Raids from the nomadic Berber people of the desert were a constant concern of those living on the edge of the desert.

 
 
 
 
The greatest change in the history of the Sahara arrived with the Arab invasion that brought camels to the region. For the first time an efficient trade across the Sahara desert could be conducted. The kingdoms of the Sahel grew rich and powerful exporting gold to North Africa. The emirates along the Mediterranean sent south manufactured goods and horses. From the Sahara itself salt was exported. This process turned the scattered oasis communities into trading centres, and brought them under the control of the empires on the edge of the desert.

This trade persisted for several centuries until the development in Europe of the caravel allowed ships, first from Portugal but soon from all Western Europe, to sail around the desert and gather the resources from the source in Guinea. The Sahara was rapidly remarginalized.

The colonial powers also largely ignored the region, but the modern era has seen a number of mines and communities develop to exploit the desert's natural resources. These include large deposits of oil and gas in Algeria and Libya and large deposits of phosphates in Morocco and Western Sahara.

 


This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Sahara".



http://www.sheppardsoftware.com/Africaweb/factfile/africauniquefact3.htm
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« Reply #1 on: August 10, 2008, 08:15:40 am »









                              The prehistory of Western Sahara in a regional context






Nick Brooks1, Savino Di Lernia2 and Nick Drake3
1Tyndall Centre for Climate Change Research and School of Environmental Sciences, University of East
Anglia, Norwich NR4 7TJ, UK. Email; nick.brooks@uea.ac.uk.
2Department of Scienze Storiche, Archeologiche, e Antropologiche dell’Antichità, Faculty of Human
Sciences, University of Rome “La Sapienza”, Via Palestro 63, 00185 – Rome, Italy. E-mail:
dilernia@uniroma1.it
3Department of Geography, King’s College, Strand, London WC2R 2LS. Email: nick.drake@kcl.ac.uk.
Extended Abstract






The disputed territory of Western Sahara has long been inaccessible to research as a result of the militaryand political conflict between Morocco, which occupies some eighty per cent of the territory, and the Frente Polisario, the Algeria-based Western Saharan independence movement.

This paper presents the findings of a two-week reconnaissance survey of the archaeology and environment of the Northern Sector of the Polisario-controlled zone of Western Sahara (Figure 1),
which took place in September and October 2002, and comprised researchers from the UK and Italy.

The results of the survey are described within thecontext of their relevance to the archaeology and environmental history of the wider Saharan region, after a consideration of the general environmental history of he Sahara as a whole.

The cultural history of the Sahara is intimately related to the existence of a succession of humid and
arid episodes, which in turn are associated with periods of global warming and cooling respectively.

Evidence from throughout the Sahara indicates that the region experienced a cool, dry and windy
climate during the last glacial period, followed by a wetter climate with the onset of the current interglacial, with humid conditions being fully established by around 10,000 BP, when we see the first evidence of a reoccupation of parts of the central Sahara by hunter gathers, most likely originating from sub-Saharan Africa
(Cremaschi and Di Lernia, 1998; Goudie, 1992; Phillipson, 1993; Ritchie, 1994; Roberts, 1998).

The cycle of glacial desiccation followed by interglacial greening is believed to be driven predominantly by variations in northern hemisphere insolation resulting from changes in the tilt of the Earth’s axis associated with the precessional cycle (Roberts, 1998).

Stronger insolation leads to increased heating of the NorthAfrican subcontinent, intensifying the African Monsoon which penetrates deep into the Sahara.

Superimposed on the interglacial humid episodes are brief periods of aridity lasting from decades to
centuries, broadly coincident with cold events in the Atlantic that appear to be manifestations of internal
climate variability that
(Alley et al. 1997; Bond et al., 1997; Cremaschi et al., 2001, 2002; Di Lernia and Palombini, 2002).

In the early Holocene, when northern hemisphere summer insolation was strong, these arid episodes were followed by recovery; however, the onset of aridity around 5000 BP was followed by a
long-term desiccation throughout the Sahara
(Cremaschi, 1998; Jolly et al. 1998; Lioubimsteva 1995).
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« Reply #2 on: August 10, 2008, 08:19:44 am »









While there is a high degree of homogeneity in the Saharan palaeoclimatic record on multi-millennial
timescales (Jolly et al., 1998; Lezine, 1989; Petit-Maire et al., 1997), the timings of arid episodes and the onset of environmental desiccation are not identical at all locations (Alley et al., 1997; Gasse and vanCampo, 1994; Goodfriend, 1991; Smith, 1998).

This may be explained by a combination of geographical differences in the nature of the principal rain-bearing systems (particularly at the extremities of the Sahara), and the mediation of climate change impacts by local surface environments. The impacts of the final climatic desiccation of the Sahara on human populations would have been strongly mediated by the rapidity and nature of the corresponding environmental desiccation. Where surface water disappeared rapidly,human populations would have been forced to migrate to wetter areas; however, in certain areas populations undertook local adaptation to gradual desiccation by exploiting refugia in which water remained as a consequence of the near-surface geology or occasional rainfall resulting from local topography
(Di Lernia et al., 2002; Mattingly et al., 2003).

The area investigated during the 2002 field survey in Western Sahara is situated between the present
day zones of westerly Atlantic rain-bearing systems to the north-west and monsoonal rainfall to the south, and is characterised by numerous ephemeral river channels. While further research is necessary to develop a detailed environmental chronology for the study area, two radiocarbon dates indicate wetter conditions in the region in the seventh millennium BP, with water present in one of the now-dry lakes in the fifth millennium BP
(Brooks et al., 2003).

These preliminary results are broadly consistent with data from the central Sahara indicating an early-middle Holocene humid episode followed by middle-late Holocene desiccation
(Petit-Maire et al., 1997).
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« Reply #3 on: August 10, 2008, 08:26:37 am »










Archaeological materials also indicate significant commonality with other Saharan regions. Acheulian
and Aterian materials, and a single trihedral point, indicate that the study area was occupied in the
Pleistocene, although the density of materials suggests that occupation may have been in the form of small, transient groups.

The density of burial sites indicates a much larger population in the Holocene, and Holocene microlithic material were also recorded.

In particular, funerary monuments representing a wide range of typologies reflect the material culture of
the central Sahara. Conical tumuli, platform burials and a V-type monument represent structures similar to those found in other Saharan regions and associated with human burials, appearing in sixth millennium BP onwards in northeast Niger and southwest Libya (Sivilli, 2002).

In the latter area a shift in emphasis from faunal to human burials, complete by the early fifth millennium BP, has been interpreted by Di Lernia and Manzi (2002) as being associated with a change in social organisation that occurred at a time of increasing aridity.

While further research is required in order to place the funerary monuments of Western Sahara in
their chronological context, we can postulate a similar process as a hypothesis to be tested, based on thehigh density of burial sites recorded in the 2002 survey.

A monument consisting of sixty five stelae was also of great interest; precise alignments north and east,
a division of the area covered into separate units, and a deliberate scattering of quartzite inside the
structure, are suggestive of an astronomical function associated with funerary rituals. Stelae are also
associated with a number of burial sites, again suggesting dual funerary and astronomical functions (Figure 2).

Further similarities with other Saharan regions are evident in the rock art recorded in the study area,
although local stylistic developments are also apparent. Carvings of wild fauna at the site of Sluguilla
resemble the Tazina style found in Algeria, Libya and Morocco (Pichler and Rodrigue, 2003), although
examples of elephant and rhinoceros in a naturalistic style reminiscent of engravings from the central
Sahara believed to date from the early Holocene are also present.

The situation at Sluguilla is unusual in that carvings are located on isolated, largely horizontal limestone slabs exposed to the elements (Figure 3).
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« Reply #4 on: August 10, 2008, 08:32:20 am »









The combination of familiar Saharan subjects and local stylistic innovation is also apparent at the
previously recorded sites of Erqeiz and Irghayra (Soler et al, 1999) and the newly identified site of Bou
Dheir (Brooks et al, 2003).

These sites are all located along elevated areas overlooking wide plains, in contrast to Sluguilla, and are associated with paintings rather than carvings. Erqeiz and Bou Dheir arenotable for their representations of large wild fauna, familiar from the central Sahara in the form of engravings
(Dupuy, 1999, Jelínek, 2000; Phillipson, 1993).

At Rekeiz an elephant and rhinoceros are depicted on the same vertical rock face in a location some distance from the main concentrations of paintings, while an elephant and a buffalo are recorded at Bou Dheir in close proximity to representations of human figures, hand prints, cattle, gazelle and a large painting that may be a wild or domesticated ovicaprid.

Giraffe are represented in paintings at Bou Dheir and Rekeiz, and in engravings at Sluguilla,indicating that they occupied an important role in the lives of the prehistoric peoples of the region, as they
did throughout the Sahara
(Dupuy, 1999; van Hoek, 2003).

Cattle feature prominently in the rock art of the Northern Sector, particularly at Erqueiz. They are also
represented at Bou Dheir, in a particularly distinctive painted style. A remarkable isolated engraving of a
cow with a smaller animal depicted inside the stomach, presumably an infant or unborn calf, was recordedon a rock at the edge of a plateau on which were located a number of funerary monuments, includingplatform and corbeille structures (Figure 4).

These images illustrate that cattle were crucial to the lives of the prehistoric peoples of Western Sahara, as they were throughout the Sahara
(e.g. Di Lernia and Palombini, 2002; Holl and Dueppen, 1999).

Ovicaprids are also a common theme in the rock paintings of the study area, although it is difficult to determine whether these images represent domestic or wild animals.

At Rekeiz and Irghrayra sheep or goats are depicted in long lines consisting of many animals. The
dominant painted panel at Bou Dheir is centred on a large image of an animal of uncertain type, possibly anovicaprid or a wild herbivore, but clearly of great significance to the artist or artists (Figure 5).
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« Reply #5 on: August 10, 2008, 08:35:59 am »









Human figures are represented only in the painted imagery recorded to date; they are absent from the
recorded engravings of Sluguilla, although their presence at unrecorded sites cannot be discounted.

Some of the figures at Bou Dheir are represented with distinctive crests or head-dresses reminiscent
of painted figures of Mediterranean or Near Eastern appearance in the central Sahara, while representations at Erqueiz are very different in appearance, suggesting at least two different population groups.

Despite the large distances involved, it appears that the far west of the Sahara around the latitude of 25°
N was far from isolated from the remainder of the greater Saharan region.

The prehistoric inhabitants of Western Sahara hunted and recorded the same animals as their counterparts
in central and eastern regions, and shared the same technologies. As throughout the Sahara, they responded to the same pressures of climatic and environmental desiccation; the location of hearths within wide river channels suggests a congregation around diminishing water resources, while the depiction of a wide variety of more humid climate fauna indicate Holocene desiccation following a humid phase.

However, many questions remain regarding the chronology of human occupation and the processes of adaptation and cultural evolution.




For example, was the region reoccupied at the same time as the recolonisation of the central Sahara, or did
transient occupation continue through the arid period that preceded the Holocene?

Did changes in funerary practices evolve in situ as societies became more stratified during the final period of desiccation, or were new practices introduced fully formed by migrants from other regions where desiccation was more advanced?

How and when were cattle introduced to the region?

In what directions did migration occur throughout the Holocene?




These questions can only be answered by further extensive research in the region, which is contingent on a continued ceasefire between the parties to the conflict, and ultimately on its peaceful and just resolution.
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« Reply #6 on: August 10, 2008, 08:43:43 am »










                                                             References





Bond, G., Showers, W., Cheseby, M., Lotti, R., Almasi, P., deMenocal, P., Priore, P., Cullen, H., Hajdas, I.
and Bonani, G. 1997. A pervasive millennial-scale cycle in North Atlantic Holocene and glacial cycles,
Science 278, 1257-1266.

Brooks, N., di Lernia, S., Drake, N., Raffin, M. and Savage, T. 2003. Geoarchaeology of the Western
Sahara: Preliminary results of the first Anglo-Italian expedition in the liberated zone. Sahara 14: 63-
80. !

Cremaschi, M. and di Lernia, S. 1998. The geoarchaeological survey in central Tadrart Acacus and
surroundings (Libyan Sahara): Environment and cultures. In Wadi Teshuinat: Palaeoenvironment and
prehistory in south-western Fezzan (Libyan Sahara) (Eds. M. Cremaschi and S. Di Lernia), pp 234-
296. Centro Interuniversitario di Ricerca per le Civiltà e l’Ambiente del Sahara Antico.Goudie, A.
1992. Environmental Change, Third Edition, Oxford University Press.

Cremaschi, M., Pelfini, M., Arzuffi, L., Di Mauro, V., Santilli, M. and Zerboni, A. 2001. A palaeoclimatic
record for the late Holocene in the central Sahara: tree rings of Cypressus dupretiana from the Wadi
Tanezzuft area (SW Fezzan, Libya). In Abstracts of the International Conference “Tree Rings and
People” (Eds. M. Kaennel Dobbertin and O, U. Braker). Davos, 22nd-26th September 2001,
Birmensdorf, Switzerland.

Di Lernia, S. and Palombini, A. 2002. Desertification, sustainability, and archaeology: indications from the
past for an African future. Origini XXIV: 303-334.

Di Lernia, S. and Manzi, G. 1998. Funerary practices and anthropological features at 8000-5000 BP. Some
evidence from central-southern Acacus (Libyan Sahara). In Wadi Teshuinat: Palaeoenvironment and
prehistory in south-western Fezzan (Libyan Sahara) (Eds. M. Cremaschi and S. Di Lernia), pp 217-
241. Centro Interuniversitario di Ricerca per le Civiltà e l’Ambiente del Sahara Antico.

Di Lernia, S., Manzi, G. and Merighi, F. 2002. Cultural variability and human trajectories in later
prehistory of the Wadi Tenezzuft, in Sand, Stones and Bones: The Archaeology of Death in the Wadi
Tannezzuft Valley (5000-2000 BP) (Eds. S. Di Lernia and G. Manzi), pp 281-302, Centro
Interuniversitario di Ricerca per le Civiltà e l’Ambiente del Sahara Antico e Delle Zone Aride,
Università Degli Studi di Roma and Department of Antiquities, Libya.

Dupuy, C. 1999. L’art rupestre à gravures naturalistes de l’Adrar des Iforas (Mali), Sahara 11, 69-86.

Gasse, F. and van Campo, E. 1994. Abrupt post glacial events in West Asia and North Africa monsoon
dynamics, Earth and Planetary Science Letters 126, 435-456.

Goodfriend, G. A. 1991. Holocene trends in 18O in land snail shells from the Negev Desert and their
implications for changes in rainfall source areas. Quaternary Research 35: 417-426.

Holl, A. F. C. and Dueppen, S. A. 1999. Iheren I. Research on Tassilian pastoral iconography, Sahara 11,
21-34.

Jelínek, J. 2000. Rock art at I-n-Leludj (Fezzan, Libya), Sahara 12, 159-163.
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« Reply #7 on: August 10, 2008, 08:47:12 am »









van Hoek, M. 2003. The Saharan “giraffe à lien” in rock art. Domesticated giraffe or rian animal?
Comparing enigmatic giraffe petroglyphs from the Sahara and Namibia, Sahara 14, 49-62.

Mattingly, D., Reynolds, T. and Dore, J. 2003. Synthesis of human activities in Fazzan. In The Archaeology of Fazzan: Volume 1, Synthesis (Ed. D. J. Mattingly), pp 327-373. Department of Antiquities, Tripoli and Society for Libyan Studies.

Petit-Maire, N., Beufort, L. and Page, N. 1997. Holocene climate change and man in the present day Sahara desert. In Third Millennium BC Climate Change and Old World Collapse (Eds. H. Nüzhet Dalfes, G.
Kukla and H. Weiss), pp 297-308. Springer-Verlag Berlin Heidelberg.

Phillipson, D. W. 1993. African Archaeology, Second Edition, Cambridge University Press.

Pichler, W. and Rodrigue, A. 2003. The “Tazina style, Sahara 14, 89-106.

Ritchie, J.C. 1994. Holocene pollen spectra from Oyo, northwestern Sudan: problems of interpretation in a hyperarid environment. Holocene 4: 9-15.

Roberts, N. 1998. The Holocene: An Environmental History. Second Edition, Blackwell Publishers Ltd.,
Oxford.

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modern research, in Sand, Stones and Bones: The Archaeology of Death in the Wadi Tannezzuft Valley
(5000-2000 BP) (Eds. S. Di Lernia and G. Manzi), pp 17-24, Centro Interuniversitario di Ricerca per le
Civiltà e l’Ambiente del Sahara Antico e Delle Zone Aride, Università Degli Studi di Roma and
Department of Antiquities, Libya.

Smith, A. B. 1998. Intensification and transformation processes towards food production in Africa. In
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and Population Dynamics at 12.000-7000 BP (Eds. S. di Lernia and G. Manzi), pp 19-33. Union
Internationale des Sciences Prehistoriques et Protohistoriques XIII World Congress, Forli, 1996.
ABACO and Centro Interuniversitardo di Ricerca sulle Civiltà e l’Ambiente del Sahara Antico, Rome.



TEXT AND FIGURES:



http://www.uea.ac.uk/sahara/publications/nb_west_abs.pdf
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« Reply #8 on: May 16, 2009, 10:31:15 pm »










                            Archaeologists Explore Prehistoric Heritage Of The Sahara





May 19th, 2008 -
ICT by admin - 
Madrid, May 19 (ANI):

A team of archaeologists is making the first catalogue of the prehistoric heritage of the Western Sahara.

The team, which comprises of Basque and Sahrawi archaeologists is exploring the region of Tiris, a
vast desert area south of Western Sahara, to find more about the past of this inhospitable region.

Led by Andoni Saenz de Buruaga, a professor at the Basque public university UPV, the team is visiting the Western Sahara for a fifth time.

We presented our research project to the Sahrawi Government in 2004. It was very well received and we have been given every chance. The results are very good, we have really made progress and that encourages us to travel for the fifth time to the region of Tiris, said Saenz de Buruaga.

The research of the Basque archaeologists covers an area of 30,000 km2, three times the surface of Navarre, a region in northern Spain.

In five years work, the Basque archeologists have catalogued more than 300 archaeological sites, including former human settlements, carvings and cave paintings. Most of them are between 3,000
and 10,000 years old.

The research work helps to make the prehistoric heritage of the southern region of the Western
Sahara better known.

We will keep on trying to research the past of the Sahrawis. It is vet important for them to know their cultural heritage, which is very rich opposite to what it was generally thought, said Saenz de Buruaga. It is a way to show and claim that their ancestors lived here, he added.

One of the most remarkable conclusions is the verification that todays arid desert was a subtropical savanna with plenty of flora and fauna six thousand years ago.

Rains decreased as a consequence of a process of climate change and animals moved to other places to face the lack of water.


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« Reply #9 on: May 16, 2009, 10:37:51 pm »


















                                                      Rivers In The Sand -



                    The Ancient Sahara May Have Harbored Waterways And Prehistoric Humans






Science News, 
August 26, 1989 
by Bruce Bower

The Eastern Sahara is one of the hottest places on Earth, its parched sands moistened by a rain shower every few decades. It may come as a surprise, then, that stretches of this African desert have inspired a scientific debate over water.

More specifically, the argument concerns ancient water. From around 2 million to 4,000 years ago, one group of investigators contends, a braided network of channels set into large valleys in the Eastern Sahara filled with flowing water during extended spells of humidity and substantial rainfall. The valleys attracted early humans at least 200,000 years ago, they say.

Another team maintains no such river system ever existed. In their view, fierce desert winds hollowed out depressions in the earth that became temporary ponds or lakes after rains. Human activity at these oases was minimal at best, they conclude.

One thing is sure: The debate owes its existence to the U.S. space program.

The first inkling that the Eastern Sahara once possessed some type of water drainage system came in 1982, when scientists at the U.S. Geological Survey (USGS) in Flagstaff, Ariz., examined radar images of Earth taken during a flight of the space shuttle Columbia. The radar penetrated large areas of the Sahara where the sand sheet is no more than several feet thick, revealing a web of valleys and smaller channels winding beneath the desert sands (SN: 4/21/84, p.224).

In 1984, guided by specially processed maps from Landsat, radar and other sources, USGS researchers located some of the radar-exposed channels with the aid of a satellite navigation device modified for land use. Excavations on the "shores" of two sand-covered valleys, directed by archaeologist William P. McHugh (who died in May), uncovered hand axes and other stone artifacts dating to approximately 200,000 years ago.

The archaeological evidence fits with geological data, described by USGS scientist John F. McCauley and his colleagues in the July 1986 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, indicating the "radar rivers" are missing links of a previously unrecognized trans-African river system. At least 30 million years ago, the researchers maintain, volcanic eruptions and shifts in the Earth's crust carved out the system's major streams, which flowed southwest from headwaters in Egypt and the Sudan, across northern Africa and into the Atlantic Ocean at the Gulf of Guinea.

The Amazonian proportions of the river system gradually receded. Geological disturbances cut off stream flow at several points in the valleys around 15 million years ago, McCauley's group says. A northward-flowing river arose about 6 million years ago and amputated still-operational sections of the river complex from its headwaters. The onset of extreme heat and virtually no rain around 2 million years ago dealt the final blow.

Nevertheless, the USGS researchers hold, ensuing rainy periods temporarily reactivated some of the rivers and streams in the Eastern Sahara. Archaeological remains indicate the streams drew groups of early humans until about 4,000 years ago, when climate changes made the area unlivable.

Archaeologist Fred Wendorf of Southern Methodist University in Dallas and his co-workers proposed a different interpretation of the radar-exposed channels in the spring 1987 JOURNAL OF FIELD ARCHAEOLOGY. They surveyed several hundred archaeological sites in and around the Eastern Sahara radar channels and concluded that no evidence supports the scenario of an ancient river system once coursing through the area. Over the last 2 million years, according to these investigators, desert winds probably dug out bedrock basins during "hyperarid" periods. The basins collected sediment and water during rainy stretches, creating transient ponds or lakes.

Archaeological sites in the survey represent short-term stops by very small groups of people, Wendorf argues. In his opinion, this confirms that prehistoric water sources in the Eastern Sahara could not support sustained human use.

The USGS scientists charge, however, that Wendorf's survey was conducted in an area where the sand is too thick for radar penetration and thus it sheds no light on the relation of prehistoric sites to the radar-exposed channels.

In a flurry of recent publications, including the winter 1988 JOURNAL OF FIELD ARCHAEOLOGY, the Feb. 24 SCIENCE and the June ANTIQUITY, McHugh and USGS scientists present further evidence for an early occupation of the African desert's ancient valleys. Uranium-series dating of carbonate found along the edges of the valleys indicates the rock was deposited in three episodes -- about 45,000 years ago, 141,000 years ago and 212,000 years ago. These deposits apparently were generated by groundwater present during phases of wet weather, the researchers contend.

McHugh's 1984 excavations, they add, uncovered stone hand axes from the 212,000-year-old carbonate deposits, providing a minimum age estimate for human occupation of the valleys. In McHugh's view, these early inhabitant's were hunters and gatherers, drawn to the game and vegetation near the riverbanks. A long succession of people followed, culminating with groups that raised cattle in the ancient valleys between 7155 and 2900 B.C.
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« Reply #10 on: May 16, 2009, 10:40:13 pm »








Around that time, according to the USGS group, the drying up to the Sahara reduced water-carrying channels to a few separate water holes, much as the billabongs of the Australian desert now lie along the courses of defunct ancient rivers.

More support for some form of prehistoric water connection in the Sahara, although not necessarily a vast river network, comes from a report soon to appear in QUATERNARY RESEARCH. Excavations conducted in 1987 at a wind-formed basin near the radar-exposed channels yielded several thousand remains of fish, amphibians, reptiles, birds and small mammals, say zoologist Kazimierz Kowalski of the Polish Academy of Sciences in Krakow and his co-workers -- including Wendorf. The fossils came from sediment dated at about 135,000 years old.

Animals uncovered at the site, including crocodiles and water turtles, indicate a large lake was once present, the researchers contend. Annual rainfall at the time was at least 20 inches, they add.

The 1987 excavations also uncovered remains of deep-water fish, now under study by paleontologist Wim Van Neer of the Royal Museum of Central Africa in Tervuren, Belgium. Only through direct water connections can these creatures colonize new areas, Van Neer says. McCauley and his USGS colleagues suggest that around 100,000 years ago, streams represented by the radar-exposed channels hooked up with water sources in the Nile Valley nearly 200 miles to the east.

Wendorf, however, still doubts humans inhabited the area for extended periods. He says the archaeological sites unearthed earthed by McHugh probably represent remains of tool workshops used intermittently over tens of thousands of years.

Althouth McHugh and his co-workers noted in the January 1988 GEOARCHAEOLOGY that their research "has literally only scratched the surface," exporation under the Saharan sands will resume in 1991, when three new space shuttle radar flights are planned. Remarks USGS geologist Carol S. Breed, "We want to map the distribution of ancient river channels across all of northern Africa."




Bibliography for

"Rivers in the sand; the ancient Sahara may have harbored waterways and prehistoric humans"




View more issues:


August 12, 1989,

August 19, 1989,

Sept 2, 1989




Bruce Bower

"Rivers in the sand; the ancient Sahara may have harbored waterways and prehistoric humans".


Science News.
August 26, 1989.
FindArticles.com.
17 Jun. 2008.


http://findarticles.com/p/articles/mi_m1200/is_n9_v136/ai_7892567
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« Reply #11 on: May 16, 2009, 10:46:32 pm »









                            Archaeologists Explore Prehistoric Heritage Of The Sahara





May 19th, 2008 -
ICT by admin - 
Madrid, May 19 (ANI):

A team of archaeologists is making the first catalogue of the prehistoric heritage of the Western Sahara.

The team, which comprises of Basque and Sahrawi archaeologists is exploring the region of Tiris, a
vast desert area south of Western Sahara, to find more about the past of this inhospitable region.

Led by Andoni Saenz de Buruaga, a professor at the Basque public university UPV, the team is visiting the Western Sahara for a fifth time.

We presented our research project to the Sahrawi Government in 2004. It was very well received and we have been given every chance. The results are very good, we have really made progress and that encourages us to travel for the fifth time to the region of Tiris, said Saenz de Buruaga.

The research of the Basque archaeologists covers an area of 30,000 km2, three times the surface of Navarre, a region in northern Spain.

In five years work, the Basque archeologists have catalogued more than 300 archaeological sites, including former human settlements, carvings and cave paintings. Most of them are between 3,000
and 10,000 years old.

The research work helps to make the prehistoric heritage of the southern region of the Western
Sahara better known.

We will keep on trying to research the past of the Sahrawis. It is vet important for them to know their cultural heritage, which is very rich opposite to what it was generally thought, said Saenz de Buruaga. It is a way to show and claim that their ancestors lived here, he added.

One of the most remarkable conclusions is the verification that todays arid desert was a subtropical savanna with plenty of flora and fauna six thousand years ago.

Rains decreased as a consequence of a process of climate change and animals moved to other places to face the lack of water.


(ANI)
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« Reply #12 on: May 16, 2009, 10:51:56 pm »










Written
By Louis Werner
Photographed
By Kevin Bubriski

SAUDIARAMCOWORLD

There are only 233 of them on Earth growing in their native soil. Some are as young as 30 years old;
others may date back two millennia. They can be 22 meters (70') tall and up to 12 meters (38') around.
In the local language, Tamashek, they are named individually, by some attribute:

“The Carpet One” or

“The One by the Flat Stones.”


Many of them drink from seasonal pools. Others must wait for the rare cloudburst to send rainwater rushing past. All somehow have learned to survive in highland “islands” within the world’s largest desert. And only a few people, including Wawa Muhammad Hamid and Muhammad Beddiaf, have seen nearly every one of them.

Hamid is a warden in southeastern Algeria’s Tassili n’Ajjer National Park, and Beddiaf is an archeologist who has walked almost every one of the park’s 100,000 hectares (386 sq mi). What is dear to both their hearts, and what they have sworn to protect, is Cupressus dupreziana—in English, the Saharan cypress, or tarout in Tamashek—listed by the International Union for the Conservation of Nature as one of Earth’s rarest tree species.

In botanical terminology, “young specimens grown in protected conditions are first bushy, later developing
a straight central axis. Bark is reddish-brown, with deep longitudinal fissures.... Branches diverge from the trunk at large angles, curving upwards.... Leaves are cupressoid scales....”

All this makes for a dignified tree, a kind of weather- and drought-beaten version of the Mediterranean cypress (Cupressus sempervirens) immortalized in the paintings of Vincent van Gogh—and all the more impressive for its harsh setting. But this comparison means little to Hamid.

“I played in these trees as a boy,” he says, remembering his childhood as a goatherd. “We took their shade, and used them as meeting points and landmarks. A traveling man might leave his belongings hanging in a bag from their limbs for years at a time, and know that everything would be waiting for him safely whenever he returned.”
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« Reply #13 on: May 16, 2009, 10:53:12 pm »

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« Reply #14 on: May 16, 2009, 10:54:27 pm »










To Europeans, conifer trees in the midst of the Sahara had been a rumor since 1860, when the
English explorer H. B. Tristram wrote in his book The Great Sahara: Wanderings South of the Atlas Mountains, “to judge from the woodwork of the [Tuareg] saddles, there is also a species of hard resinous wood probably allied to junipers.” He was close: The Juniperus genus is adjacent to the Cupressus genus within the cypress family, Cupressaceae.

Still, this cypress species was not described scientifically until 1924, after it was seen by the man
for whom it is named, Captain Duprez, commander of French forces at Fort Charlet in the Djanet oasis, at the foot of the nearly 2000-meter-high (6500') Tassili plateau. He wrote to a biologist, “I discovered one day in a small wadi called Tamrit a tree with foliage and habit too unusual for the area not to attract my attention.” At the time, only a handful of these cypresses were said to be in existence, their seeds were thought to be sterile, and their extinction was anticipated in a matter of years.

Today, the Saharan cypress has better chances of survival. In part, this is thanks to investigations
by Algerian paleoecologist Fatiha Abdoun, the one person who has seen every Saharan cypress still alive in its native habitat. Two young trees in Wadi Tamrit, where many are clustered, were thought to have slim odds of survival when French botanists measured them in the 1950’s but, five decades later, Abdoun has found them healthy. Their slow, two-millimeter-per-year radial growth rates compare well with those of their close cousin the Atlas cypress (Cupressus atlantica), whose habitat in Morocco’s High Atlas mountains has an annual rainfall 15 times greater than that of the Tassili. And no less fittingly, that first tree found by Captain Duprez is thought to be still alive and healthy at the head of the wadi.

But if the tree has proved to be successful in germinating, taking root and adapting to increasingly arid conditions, Abdoun says it may not be able to outwit its latest challenge: growing numbers of mostly European tourists, led by the commercial outfitters who have flourished since the end of the Algerian civil war in the late 1990’s. They flock to the Tassili plateau not so much for the trees, but to view a remarkable gallery of late Paleolithic and Neolithic rock art.
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