학술논문

Climate change in the Turkana basin as deduced from a 4000 year long [delta]O.sup.18 record
Document Type
Report
Author abstract
Source
Earth and Planetary Science Letters. July, 1996, Vol. 142 Issue 1-2, p7, 11 p.
Subject
Climatic changes
Language
English
ISSN
0012-821X
Abstract
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/0012-821X(96)00094-5 Byline: R.D. Ricketts (a), T.C. Johnson (b) Abstract: A model of the oxygen isotopic composition of Lake Turkana waters sheds insight into the paleoclimatic interpretation of a [delta].sup.18O profile of inorganic calcite from a core taken from the lake. The model indicates that high frequency fluctuations seen in the isotopic record are probably due to shifts in lake level, while the long term increase of 1.4a[degrees] seen from 4 to 2 kyr BP cannot be due solely to lake level change. It must be due to changes in other climatic parameters, such as the isotopic composition of the inflow. These findings suggests that the abrupt change observed in Lake Turkana (and many other African lakes) at 4 ka was the precursor to a 2000 year long adjustment in the climate over the Ethiopian Plateau. The isotopic record from Lake Turkana agrees with other paleoclimate records from the basin, including the diatom stratigraphy and radiocarbon dates on exposed shoreline deposits. Author Affiliation: (a) Duke University Geology Department, Durham, NC 27708,USA (b) Large Lakes Observatory, University of Minnesota, Duluth, MN 55812,USA Article History: Received 12 January 1996; Accepted 29 April 1996