Monsoon-driven Saharan dust variability over the last 240,000 years: Implications for Plio-Pleistocene African climate evolution
Abstract
Records of Saharan dust deposition in marine sediments provide foundational records of North African climate over 103-106 year timescales. Previous records show primarily glacial-interglacial variability in the Pleistocene, in contrast to other monsoon records dominated by precessional variability. Here we present the first Saharan dust record spanning multiple glacial cycles obtained using 230Th-normalization, an improved method of calculating fluxes. Contrary to previous data, our record demonstrates high correlation with summer insolation and limited glacial-interglacial changes, indicating coherent variability in the Afro-Asian monsoon belt throughout the late Pleistocene. Our analysis indicates that previous data using dust percentages and age model-based dust accumulation rates are biased by carbonate dissolution during glacial maxima, which creates spurious dust percentage and dust accumulation peaks at 41- and 100-kyr periodicities. Our results demonstrate that low-latitude Saharan dust emissions do not vary synchronously with high- and mid-latitude dust emissions, and they call into question the use of existing Plio-Pleistocene dust records to investigate change points in North African climate and links between climate and hominid evolution.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP31A..06M
- Keywords:
-
- 1616 Climate variability;
- GLOBAL CHANGEDE: 4914 Continental climate records;
- PALEOCEANOGRAPHYDE: 4928 Global climate models;
- PALEOCEANOGRAPHYDE: 4934 Insolation forcing;
- PALEOCEANOGRAPHY