Early to Middle Miocene Orbitally-Paced Climate Dynamics in the Eastern Equatorial Atlantic

• DOI: 10.22541/essoar.169603559.98313623/v1
• Publication Date: 2023-09-30T01:00:02Z
• Authors: Bianca Robin Spie...; Evi Wubben; Frits Hilgen; Appy Sluijs
• Keywords: Precession; Milankovitch cycles; Eccentricity (behavior); paleoceanography; Paleoclimatology; Forcing (mathematics); Orbital forcing

Detailed analysis of tropical climate dynamics is lacking for the Early to Middle Miocene, even though this time interval bears important analogies future climates. Based on high-resolution proxy reconstructions sea (sub)surface temperature, export productivity and dust supply at Ocean Drilling Program Site 959, we investigate orbital forcing West African monsoon in eastern equatorial Atlantic across prelude, onset, continuation Miocene Climatic Optimum (MCO; 18-15 Ma). Along with previously identified eccentricity periodicities ~400 kyr ~100 kyr, our records show that varied ~27-17 ~41 ~60-50 timescales, which attribute precession, obliquity, their combination tones, respectively. Three intervals distinct variability were recognized: (1) strong eccentricity, precession prior MCO (18.2-17.7 Ma), (2) influence obliquity just after onset (16.9-16.3 Ma) concurring a node 2.4 Myr cycle, (3) dominant during between 16.3 15.0 Ma. Sedimentation 959 was influenced by orbitally-paced variations upwelling intensity North aridity related dynamics. Continuously present patterns imply low-latitude forcing, while asymmetric imprints suggest also affected high-latitude, glacial-interglacial