The camp is effaced, its pavilions and lean-tos,at Miná – both Ghawl and Rijám desolate –and the torrent-beds of Er-Raiyán—their traces stripped,made smooth, like old lettering scored on a stone;the ashes – since the people who left them tarried hereyears have repeated their months ordinary and sacred.…I stopped to ask the place – but how can we questionsolid rocks, whose speech is incomprehensible?…

Labíd ibn Rabi'a, c. 600 CE(trans. after AJ Arberry and Eric Ormsby)

The Sahara landscape over the Holocene

• life in the Hoggar (southern Algeria) c.9000 to 4000 BP

• stratigraphic approaches to reconstructing Saharan vegetation and hydrology

• a chronology

• a speculation

Nir Krakauer

the setting

Hoggar

Aïr

Tibesti

Hoggar

Tassilin’Ajjer

the Tassili n’AjjerAtlantis,

199

0

Henri LhoteM. Henri Lhote (1956)

copying the picturesrock…

to paper

the ‘round-headed’, hunting phases

herding (Bovidian) phases

What happened?

• a chronology of Holocene conditions in the Sahara has been reconstructed primarily from the following 14C datable materials:– ocean sediments– lake-bed carbonates, peat,diatoms – pollen

the Sahara was dustier at the

glacial maximum…

Ruddiman 1997

and less dusty in the mid-Holocene

Hoelzmann, Jolly et al 1998

pollen sitessabkhas, middens…

some vegetation m

apping: a legend

(E Shulz &

coworkers)

N Africa 8,000 y before-present

nowadays

the expandable Chad-Niger basin

the Servants: some lake level histories

Servant and Servant-Vildary 1980

the P/E index -diatom reconstructionServant and Servant-Vildary 1980

savanna

desert

Lake Chadbasin moisture

% terr. offMauritania

degradation

N Nigerpollen

Sahelriverdeposits

14CkyBP

ephemeralbraided

meandering

deflationbraided

deflationbraided

ephemeral

Tibestisilt terraces

aeolian + calcrete

humanartifacts

more sites

epi-paleolithic

neolithic

potterysheep& cow domestic

herding spreads

round -head

period?

Bovid

ian period?

Egypt: Old Kingdom

the bigpicture

a speculation on the Afroasiatic language family

or, Fermi’s question

Egyptian

5000

Akkadian4500

Canaanite3800

Somali

N Arabic2000

Hausa

Amharic1700

S Arabic2700

credits• z

http://www.nationalgeographic.com/resources/ngo/maps/view/africam.html

• http://perso.wanadoo.fr/mohamed.sahnoun/Images/algeriamap.jpeg

• http://www.tara.org.uk/images/tassili.gif• http://www.paleologos.com/• http://rsta.pucmm.edu.do/biblioteca/pinacoteca/arte

%20prehistorico/prehistoria%20p1.htm• http://home.t-online.de/home/Jochen_Baumann/ • http://worldroom.tamu.edu/mideast/photos/sts036-152-252.jpg• http://www.edunetconnect.com/cat/timemachine/images/

scan1.gif• http://www.uni-wuerzburg.de/geographie/fachi/

pal_atlas_afrika/index_atlas.htm#start• http://www.ship.edu/~cgboeree/languagefamilies.html

printed referencesLhote H (trans. A Brodrick) The Search for the Tassili Frescoes, New York, 1959

• Ruddiman WF, Marine Geology 136:189-207(1997)• deMenocal P, J Ortiz et al Quat Sci Rev 16:347-

61(2000)• Hoelzmann P, D Jolly et al Global Biogeochem Cycles

12:35-51(1998)• Schulz E, Hydrobiologia 214:359-65(1991)• Talbot MR, in The Sahara and the Nile (MAJ Williams

and H Faure, eds.), 37-62, Rotterdam, 1980 • Servant M and Servant-Vildary S, in The Sahara and the

Nile (MAJ Williams and H Faure, eds.), 133-162