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Accurately calibrated XRF-CS record of Ti/Al reveals Early Pleistocene aridity/humidity variability over North Africa and its close relationship to low-latitude insolation.
- Source :
- Climate of the Past Discussions; 2/28/2022, p1-20, 20p
- Publication Year :
- 2022
-
Abstract
- In eastern Mediterranean Sea sediments, the titanium to aluminum ratio (Ti/Al) captures relative variability in eolian to riverine derived material, and predominantly integrates climate signals over the Saharan and Sahel regions. Long Ti/Al time series can, therefore, provide valuable records of North African humidity/aridity changes. X-ray fluorescence core scanning (XRF-CS) can generate near-continuous Ti/Al records with relatively modest effort and in an acceptable amount of time, provided that accurate Ti/Al values are acquired. Calibration of the raw XRF-CS data to those of established analytical methods is an important pathway to obtain this required accuracy. We assess how to obtain reliable XRF-CS Ti/Al calibration by using different sets of calibration reference samples for a long sediment record from ODP Site 967 (eastern Mediterranean). The accuracy of reference concentrations and the number of reference samples are important components for reliable calibration. The acquired continuous Ti/Al record allows detailed time-series analysis over the past 3 Ma. A near-direct control of low-latitude insolation on the timing and amplitude of North African aridity/humidity is observed from 3 to ~1.2 Ma. It is evident from our Ti/Al record that the most arid North African intervals (i.e., with longest period and highest amplitude) occur after the mid-Pleistocene transition (MPT; ~1.2-0.7 Ma). Concurrently, correlation between North African aridity/humidity (Ti/Al) and higher latitude climate signals (ice-volume variability) increases around the MPT. These findings support the growing consensus that African climate became more sensitive to remote high-latitude climate when a threshold ice volume was reached during the MPT. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 18149324
- Database :
- Complementary Index
- Journal :
- Climate of the Past Discussions
- Publication Type :
- Academic Journal
- Accession number :
- 155558359
- Full Text :
- https://doi.org/10.5194/cp-2022-14