Changes in sedimentation in the Caribbean Sea before, during and after the shoaling of the Central American Seaway

The Pliocene, a pivotal period in Earth's climatic evolution, holds immense significance. It marks the transition from a notably warmer period, with no permanent ice in the northern hemisphere, to the colder phases associated with the Pleistocene glacial periods. Several geological events were significant during the Neogene, but one of the most crucial was the closure of the Isthmus of Panama. This land bridge, connecting the North and South American continents, formed primarily through the convergence of the Cocos plate, the Caribbean plate, and the Panama microplate, resulting in widespread orogeny and intense volcanism. This study is based on textural, mineralogical, and geochemical proxies derived from samples collected in the Caribbean Sea basin at site 999A of the ocean drilling program (ODP). It aims to understand the influence of the closure of the Isthmus of Panama and climate change on sedimentation in the study area (Colombian Basin). The geochemical and mineralogical data suggest that orbital (Milankovitch) cycles influenced sedimentation patterns in the Caribbean Sea during the Pliocene due to substantial changes in regional precipitation. However, after the shoaling of the Central American seaway, approximately 4 million years ago, the expression of these cycles in sedimentation in the study area decreased. The impact of these orbital cycles on precipitation began to diminish as the North Atlantic and the Caribbean Sea warmed. This shift had profound implications for climate dynamics, causing the Intertropical Convergence zone to migrate northward. With the onset of the Pleistocene, approximately 2.58 million years ago, the relevance of orbital forcing reemerged, fundamentally influencing sedimentation in the Caribbean Sea and specifically affecting precipitation patterns in the equatorial region and the South American monsoon system. Understanding this complex interaction is crucial, as it highlights how geological and climatic factors have shaped our modern environment.