Orbital Forcing and Evolution of the Southern African Monsoon From Late Miocene to Early Pliocene

• Published in: Paleoceanography and Paleoclimatology
• Main Authors: Queiroz De Azevedo, Allana, Jiménez-Espejo, Francisco José, Escutia Dotti, Carlota
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2023
• Subjects: Antarc*; Antarctic; Ice Sheet; Planktonic foraminifera
• Online Access: https://hdl.handle.net/10481/84906; https://doi.org/10.1029/2022PA004588

This research used samples provided by the International Ocean Discovery Program (IODP). The authors thank to Editor Dr. Ursula Röhl, Dr. Christian Zeeden, and the anonymous reviewer for improving the quality of our study providing critical review of it. The authors thank to the Operational Oceanography and Paleoceanography Laboratory (LOOP—Brazil), the Andalusian Earth Sciences Institute (IACT—Spain), the University of Granada (UGR—Spain), and the University of Salamanca (USAL—Spain) for all infrastructure and support. The first author thanks to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—CAPES for Ph.D. fellowship (process 88887.372122/2019‐00). FJJE and CE has been supported by the Spanish Ministry of Science and Innovation (Grant CTM2017‐89711‐C2‐1‐P), cofunded by the European Union through FEDER funds. The late Miocene-early Pliocene (7.4-4.5 Ma) is a key interval in Earth's history where intense reorganization of atmospheric and ocean circulation occurred within a global cooling scenario. The Southern African monsoon (SAFM) potentially played an important role in climate systems variability during this interval. However, the dynamics of this important atmospheric system is poorly understood due to the scarcity of continuous records. Here, we present an exceptional continuous late Miocene to early Pliocene reconstruction of SAFM based on elemental geochemistry (Ca/Ti and Si/K ratios), stable isotope geochemistry (δ18O and δ13C recorded in the planktonic foraminifera Orbulina universa), and marine sediment grain size data from the International Ocean Discovery Program (IODP) Site U1476 located at the entrance of the Mozambique Channel. Spectral characteristics of the Si/K ratio (fluvial input) was used to identify the main orbital forcing controlling SAFM. Precession cycles governed precipitation from 7.4 to ∼6.9 Ma and during the early Pliocene. From ∼6.9 to ∼5.9 Ma, the precession and long eccentricity cycles drove the SAFM. The major Antarctic ice sheet expansion across this interval ...