Respuesta ambiental en el Pacífico frente a la subducción de la dorsal asísmica de Cocos (Panamá y Costa Rica)

Abstract

Environmental response in the Pacific to aseismic Cocos Ridge subduction (Panama and Costa Rica). The evolution of the marine communities along the Pacific coast of Central America, may have changed in response to the formation of the Isthmus of Panama. To evaluate the effect of the Aseismic Cocos Ridge (DAC) subduction on the marine benthic communities, we reconstructed benthic assemblages from Neogene fossiliferous formations in Burica and Nicoya peninsulas of Panama and Costa Rica. Paleoecological and paleoenvironmental conditions were reconstructed by comparing community structure from bulk fossil samples with dredge collections from modern Tropical American seas, using principal component analysis. Our results indicate that during the early Pliocene, before the closing of the Isthmus, some oceanic islands existed with moderate upwelling in the Burica region. After the closure, during the late Pliocene and early Pleistocene the collision of the DAC caused an uplift of the seafloor, where water depth of 2 300m became shallow waters of less than 40m depth. Meanwhile, upwelling intensified in the open ocean the uplift that had formed small islands in coastal areas of Burica, creating protected areas and limiting the upwelling effect that was given in open ocean. The subduction of the DAC continued until the islands were joined to the mainland and gradually disappeared, allowing the return of the upwelling. During the middle Pleistocene a second process of accelerated uplift with speeds of 8m/1 000 years provoked again the elevation of the seafloor and later the elevation of the Talamanca Range. The new range formed a barrier that blocked the passage of the Trade winds, created new ecological conditions and optimized and allowed the growth of the best coral reefs in the coasts of the tropical Eastern Pacific (POT) between Panama and Costa Rica. Rev. Biol. Trop. 60 (2): 893-908. Epub 2012 June 01.

Shark-cetacean trophic interactions during the late Pliocene in the Central Eastern Pacific (Panama)

“…The fossil record of the Burica Formation includes foraminifera, mollusks, crustaceans, fish otoliths, and shark teeth (Olsson, 1942;Corrigan et al, 1990;Collins et al, 1995;De Gracia et al, 2012;De Gracia, 2015;Carrillo-Briceño et al, 2018, table S6). The record presented here represents the first occurrence of mammal remains from this succession.…”

“…That allowed the Charco Azul Group to become exposed subaerially in the Burica Peninsula (Figure 1.2) (Corrigan et al, 1990;O'Dea et al, 2012). The Charco Azul Group is a 4500 m thick succession of marine sediments (Olsson, 1942;Coates et al, 1992;O'Dea et al, 2007) comprising the Peñita, Burica, and Armuelles Formations (Leon-Rodriguez, 2007;De Gracia et al, 2012) (Figure 1.3).…”

Marco Conceptual Para Investigaciones Tsunamigénicas: Caso Litoral Pacífico Colombiano

“…Morton et al, 2000) y subsidencia repentina debido a algún evento tectónico, es una herramienta importante en la investigación de paleotsunamis; ejemplos claros son los estudios realizados en las costas de Costa Rica, Ecuador y México, en donde se han registrado cambios en la vegetación como efecto de la subducción de dorsales (de Gracia et al, 2012), y la inundación por tsunamis (Ramírez-Herrera, 2011;Lim et al, 2013).…”

Bridging two oceans: small toothed cetaceans (Odontoceti) from the Late Miocene Chagres Formation, eastern Caribbean (Colon, Panama)

“…The younger Chagres Fm. was deposited during the Late Miocene and includes the fossiliferous Chagres Sandstone Member that preserves chondrichthyans teeth [23], bony fish skeletons and otoliths [24][25][26][27], and odontocetes [16,17,28].…”