Environmental response in the Pacific to aseismic Cocos Ridge subduction (Panama and Costa Rica)

摘要: The evolution of the marine communities along Pacific coast Central America, may have changed in response to formation Isthmus Panama. To evaluate effect Aseismic Cocos Ridge (DAC) subduction on benthic communities, we reconstructed assemblages from Neogene fossiliferous formations Burica and Nicoya peninsulas Panama Costa Rica. Paleoecological paleoenvironmental conditions were by comparing community structure bulk fossil samples with dredge collections modern Tropical American seas, using principal component analysis. Our results indicate that during early Pliocene, before closing Isthmus, some oceanic islands existed moderate upwelling region. After closure, late Pliocene Pleistocene collision DAC caused an uplift seafloor, where water depth 2 300m became shallow waters less than 40m depth. Meanwhile, intensified open ocean had formed small coastal areas Burica, creating protected limiting was given ocean. continued until joined mainland gradually disappeared, allowing return upwelling. During middle a second process accelerated speeds 8m/1000 years provoked again elevation seafloor later Talamanca Range. new range barrier blocked passage Trade winds, created ecological optimized allowed growth best coral reefs coasts tropical Eastern (POT) between