final english presentation sahara
Post on 02-Jul-2015
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SAHARA 5000 YEARS AGO
Maquinghen Arnaud
Teacher : Chris Yukna
1
TODAY
Without external water
Day : 50°C
Night : -10°C
More than 1 million tonne
of dust particles
2
MIT SEARCHING
Sahara transformate to its current state 4900
years ago.
MIT’s research : quantity of dust and the
aridity are proportionnal
Studying Algeria, Mauritania and Senegal
3
USING MARINE SEDIMENTS
Quantifying the number of mineral particles
of ground origin present in marine sediments.
4
STORY OF SAHARA DURING HOLOCENE
Wet period : 11800 to 5800 years ago
Dust particles 7000 years ago was 5 time
lower than those last 2000 years.
Oceanic slope of north Africa
Uranium-thorium method
5
SAHARA MORE THAN 5000 YEARS AGO
Sahara was covered with meadows and not
with savannas or with deserts as today
6
CONCLUSION
Sahara changed quickly
This method can help us to understand and
predict our current climate-change.
7
THANK YOU FOR YOUR ATTENTION
Question ?
8
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