ARPN Journal of Science and Technology Logo

ARPN Journal of Science and Technology >> Volume 7, Issue 1, January 2017

ARPN Journal of Science and Technology


Lake Level Variations for the Last 30,000 Yr B.P: New Palaeoclimatic Synthesis in Northern Hemisphere of Africa

Full Text Pdf Pdf
Author Brahim Damnati, Khadija Ait Lemquedem, Hajer Benjilani, Mouna El Afia, Khalid El Khoudri
ISSN 2225-7217
On Pages 766-773
Volume No. 4
Issue No. 12
Issue Date January 01, 2015
Publishing Date January 01, 2015
Keywords Climate, Lakes, data, Africa northern Hemisphere, last glacial maximum, Holocene



Abstract

Lake level fluctuations are one of the most important sources of palaeohydrological and palaeoclimatic information for continental areas over the late Quaternary. We have compiled old and new published lake status data from North African basins, over tree periods: between 30,000 and 21,000 yr B.P, ca 9,000 yr B.P and ca 6,000 yr B.P. Between 30,000 and 21,000 yr B.P, one or two relatively humid episodes have been identified in northern hemisphere of Africa. However, at 21,000 yr B.P, Low or intermediate lake status was registered in the Sahara, in west and east Africa north equator. The scarcity of data in this period globally reflects severe desiccation, deflation and erosion in many basins. Its clear that the late glacial maximum was significantly dry in this area. At 9,000 yr B.P, many lakes began to rise. Some of them receded dramatically after 11,000 yr B.P. The majority of lakes with this initial amelioration was in north-east Africa in equatorial zone. The large perturbation is occurred in northern Africa. Between 0 and 22N, nearly all lakes were high. The water status responded first near the equator (between 0 and 10N) and subsequently rises progressively in Sahara and Sahel. The main period of positive hydrological conditions was recorded simultaneously in lacustrine systems in interdunal depression and in Sebkhas in Mauritania, Mali, Eastern Niger and Sudan. At 6,000 yr B.P, the lakes show a more positive water balance over northern Africa. The southern margin of the zone of wetter conditions is unchanged relative to 9,000 yr B.P, but evidence from two sites in the Libyan desert suggests that the northern boundary may have been slightly further north. There is a suggestion that conditions became wetter than 9,000 yr B.P (and today) in the Maghreb.


Back
Seperator
    Journal of Computing | Journal of Systems and Software     
Copyrights
2014 ARPN Publishers