|
|||||
|
|
Multiple phases of North African humidity recorded in lacustrine sediments from the Fazzan Basin, Libyan Sahara |
|
| Authors: | SJ Armitage NA Drake S Stokes A El-Hawat MJ Salem K White P Turner SJ McLaren |
| Institution: | aOxford University Centre for the Environment, Dyson Perrins Building, South Parks Road, Oxford OX1 3QY, UK bDepartment of Geography, Kings College, London WC2R 2LS, UK cEarth Sciences Department, University of Garyounis, P.O. Box 1308, Binghazi, Libya dEarth Sciences Department, Al-Fateh University, P.O. Box 13040, Tripoli, Libya eDepartment of Geography, The University of Reading, Whiteknights, Reading RG6 6AB, UK fSchool of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK gDepartment of Geography, University of Leicester, University Road, Leicester LE1 7RH, UK |
| Abstract: | The Fazzan Basin of south-west Libya is at present arid with less than 20 mm of rainfall per annum. However, regionally extensive limestones, lacustrine sands and coquina (fossiliferous carbonate rock) deposits show that the Fazzan Basin previously contained a large palaeolake, indicating that the climate in the past was more humid. Optically stimulated luminescence (OSL) dating techniques have been applied to key lacustrine deposits within the basin in an attempt to provide an internally consistent chronology for this humidity record. Results indicate that palaeolake sediments within the Fazzan Basin record a very long history of palaeohydrological change, ranging from present day arid conditions to humidity capable of sustaining a lake with an approximate area of 76,250 km2. The existence of humid periods in mid oxygen isotope stage 5 and the early Holocene is confirmed. An older lacustrine event, tentatively correlated to oxygen isotope stage 11, is also recognized. In addition, evidence is presented for at least two humid phases beyond the age range over which the conventional OSL dating technique is applicable. This study demonstrates that OSL dating of palaeolake sediments within the Fazzan Basin offers the potential to provide a detailed record of North African humidity spanning several glacial–interglacial cycles. |
| Keywords: | Libya Sahara Palaeolake Fazzan Optically stimulated luminescence dating |
| 本文献已被 ScienceDirect 等数据库收录！ | |