Gazel, E., Hayes, J., Hoernle, Kaj , Holbrook, Steven W., Kelemen, P. and Carr, M. J. (2012) The extensive record of Galapagos-tracks interaction with the Central American subduction system: A natural laboratory for the evolution of continental crust. [Talk] In: The Lübeck Retreat, Collaborative Research Centre SFB 574, Volatiles and Fluids in Subduction Zones: Climate Feedback and Trigger Mechanisms for Natural Disasters. , 23.05.-25.05.2012, Lübeck . The Lübeck Retreat - final colloquium of SFB 574, May 23-25, 2012: program & abstracts. ; p. 6 .

Abstract

Although most Central American magmas have a depleted MORB-source mantle (fluxed by subduction-derived fluids), magmas in southern Central America (Costa Rica and Panama) have
isotopic and trace element compositions with a Galapagos affinity. How Galapagos-influenced
signature was introduced into the Central American mantle has been at the heart of the conflicting theories. Our new data collected as collaboration during the SFB 574, allowed us to produce the most complete reconstruction of the evolution of subduction system (Costa Rica, 30-0 Ma and Panama, 70-0 Ma) ever produced. We discovered that the Galapagos signature has a relatively recent origin (<10 Ma) and correlates with the interaction of geochemically enriched Galapagos tracks with the
subduction system. After this dramatic change in subduction input magmas from southern Central
America not only inhered an anomalous Galapagos isotopic signature but also evolved from primitive arc geochemistry to compositions closer to continental crust. Recent seismic velocity models from the TICO-CAVA active source project in Costa Rica also suggest that this island arc is the closest to continental crust. The evolution of the arc into a continental land-mass culminated in the formation land bridge that allowed exchange of fauna between the Americas and changed global oceanic circulation and climate. Finally, the evolution towards a continental character makes this a unique location a natural laboratory to test different models of continental evolution in the early Earth.

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