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Accurately calibrated X-ray fluorescence core scanning (XRF-CS) record of Ti / Al reveals Early Pleistocene aridity and humidity variability over North Africa and its close relationship to low-latitude insolation.
- Source :
- Climate of the Past; 2022, Vol. 18 Issue 11, p2509-2521, 13p
- Publication Year :
- 2022
-
Abstract
- In eastern Mediterranean sediments, the titanium-to-aluminum ratio (Ti/Al) captures relative variability in eolian to river-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 and 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 raw XRF-CS data to those of established analytical methods is an important pathway for obtaining the required accuracy. We assess how to obtain reliable XRF-CS Ti/Al calibration by using different calibration reference sample sets for a long sediment record from ODP Site 967 (eastern Mediterranean Sea). The accuracy of reference concentrations and the number of reference samples are important for reliable calibration. Our continuous Ti/Al record allows detailed time series analysis over the past 3 Myr. Near-direct control of low-latitude insolation on the timing and amplitude of North African aridity and humidity is observed from 3 to ∼ 1.2 Ma. In our Ti/Al record, most arid North African intervals (i.e., with the longest period and highest amplitude) occur after the mid-Pleistocene transition (MPT; ∼ 1.2–0.7 Ma), when ice ages intensified. We also observe a subdued relationship between low-latitude insolation and North African climate after 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
- Volume :
- 18
- Issue :
- 11
- Database :
- Complementary Index
- Journal :
- Climate of the Past
- Publication Type :
- Academic Journal
- Accession number :
- 160815918
- Full Text :
- https://doi.org/10.5194/cp-18-2509-2022