The Middle America Trench in the Geological Framework of Central America

Along and across arc geochemical variations in NW Central America: Evidence for involvement of lithospheric pyroxenite

“…An extensive overview of the Central American geology can be found in e.g. Auboin et al (1982), Carr et al (1990Carr et al ( , 2003, and Protti et al (1995). Below we summarize the Central American geology pertinent to this study.…”

“…The sediment input, which has been well-defined at Deep Sea Drilling Project (DSDP) Site 495 ( Fig. 1), can be divided into a lower, $250 m thick, unit of carbonate ooze and an overlying, $200 m thick, unit of hemipelagic clay (Auboin et al, 1982;Plank and Langmuir, 1998;Patino et al, 2000;Sadofsky et al, 2008). The composition of the igneous portion of the Cocos Plate outboard of Guatemala is characterized by samples from Site 495 (in this study and Geldmacher et al, 2008) and outboard of Nicaragua by drill (Site 1256; Sadofsky et al, 2009) and dredge samples (from an off-axis seamount; Werner et al, 2003).…”

U‐series disequilibria in Guatemalan lavas, crustal contamination, and implications for magma genesis along the Central American subduction zone

“…The age of the subducting Cocos lithosphere is approximately constant (about 26 Ma) along most of the subduction zone, except along its southeasternmost segment in central Costa Rica where slightly younger (∼17 to 25 Ma) lithosphere, generated at the Cocos‐Nazca spreading center, is being subducted [ Harry and Green , 1999; von Huene et al , 2000; Barckhausen et al , 2001]. The sedimentary section crowning the subducting Cocos plate is also thought to be relatively uniform along the length of the subduction zone, broadly consisting of: pelagic carbonates overlain by hemipelagic oozes [ Aubouin et al , 1982; Kimura et al , 1997]. Both units are geochemically distinct and both are believed to substantially contribute to the slab signal seen in erupted basaltic magmas, except perhaps in central Costa Rica [ Morris et al , 1990; Plank and Langmuir , 1993; Reagan et al , 1994; Patino et al , 2000; Walker et al , 2000, 2001; Carr et al , 2003].…”

Volcanism and geochemistry in Central America: Progress and problems

“…From Guatemala to northwestern Costa Rica the age, source and stratigraphy of the Cocos Plate crustal section are similar, suggesting a near uniform input [Aubouin et al, 1982;Kimura et al, 1997]. The tectonic processes along the Cocos -Caribbean convergent margin result in the subduction of most of the Cocos sediment section, which is clearly imaged tens of kilometers landward of the trench [von Huene et al, 2000].…”