Chronological and Causal Perspectives on the Tectonic Evolution of Equatorial Atlantic

The Equatorial Atlantic Ocean, a region crucial to understanding Earth’s tectonic processes and advancing the theory of plate tectonics, remains the focus of extensive research aimed at unraveling its evolution. However, its complex structural setting and contentious formation timeline have posed significant challenges. Through a comprehensive review of contemporary scientific literature, we have identified three distinct phases for its evolution: pre-breakup, syn-breakup, and post-breakup, providing more detailed insights into the tectonic evolution of the Equatorial Atlantic. Prior to 110 Myr, the African and South American Plates underwent stretching predominantly from North to South, with the emergence of the Parana plume. This condition has led to the formation of numerous fracture zones and a triple junction. During the syn-breakup phase, spanning from 110 Myr to 90 Myr, the central region of the Equatorial Atlantic fully opened up, establishing a connection between the northern and southern waterways. However, the development of multiple ridge segments separated by numerous fracture zones in the central Equatorial Atlantic exhibited considerable complexity. The underlying causes for these complex structural formations remain elusive. Following the Chicxulub meteorite impact around 66 Myr and the emergence of the Sierra Leone hotspot, a pair of oceanic plateau ‘twins’ and a series of seamount chains were formed as a result of mantle plume tails. Consequently, the timeline of the Equatorial Atlantic’s tectonic evolution has gradually become clearer. However, due to the extensive timescale and the multitude of events involved in its formation, disputes about the precise timing of various events still remain. The evolution of the Equatorial Atlantic has witnessed numerous ridge propagations, hotspot formations, and meteorite impacts, highlighting the need for further investigation into their interactions. The absence of identified magnetic isochrons in the Equatorial region emphasizes the urgency of additional exploration and analysis of its geological and geophysical data.