Late Cretaceous arc development on the SW margin of the Caribbean Plate: Insights from the Golfito, Costa Rica, and Azuero, Panama, complexes

Abstract

[1] The processes of arc initiation at the margin of an oceanic plateau are remarkably well preserved along the southern coastline of eastern Costa Rica and western Panama. We present new results of a combined tectonostratigraphic and petrologic study with which protoarc initiation (75-73 Ma) at the margin of an oceanic plateau (89-85 Ma) is documented. Dykes of protoarc igneous rocks within the plateau and occurrences of protoarc igneous rocks are widely distributed. These types of field observations, geochemical data, and paleontologic ages for Late Cretaceous to Eocene fore-arc rocks of the Golfito Complex and Azuero Marginal Complex (southern Costa Rica and western Panama) provide the first direct evidence that a Coniacian-early Santonian oceanic plateau forms the arc basement. Stratigraphic and geochemical constraints from Golfito and Azuero indicate subduction initiation in south Central America, associated with geochemically distinctive suprasubduction igneous rocks, occurred in the late Campanian along the margin of the newly defined Azuero Plateau. Overall, the Golfito Complex and Azuero Marginal Complex provide a significant opportunity for exploration of petrologic mechanisms linking some oceanic plateaus to the growth of continents. The Azuero Plateau may extend further toward the Colombian Basin and forms thickened Caribbean crust. It served as a nucleus for accretion of additional oceanic plateaus, seamounts, and oceanic islands of Pacific origins.

Kinematic reconstruction of the Caribbean region since the Early Jurassic

“…Boundaries of this block are the Panama Deformed Belt in the northeast, the Central American trench in the west (where the Cocos plate, Cocos Ridge and Nazca plate are subducting), a diffuse thrust belt in the Cordillera Central of Costa Rica in the northwest, and the suture with the South American continent in the southeast (Buchs et al, 2010). The bulk of the Panama-Costa Rica land bridge is composed of upper CampanianNeogene volcanic arc rocks (Denyer et al, 2006;Buchs et al, 2010;Montes et al, 2012) underlain by oceanic plateau crust, as suggested by geochemical characteristics of recent magmas (Feigenson et al, 2004;Gazel et al, 2009). 40 Ar/ 39 Ar ages of oceanic plateau fragments range from 139 to 71 Ma Hoernle et al, 2002Hoernle et al, , 2004.…”

“…3. Tectonic map of the Caribbean region, showing the tectonic blocks as described in Section 3 and locations of arc material (from Iturralde-Vinent et al, 2008;Krebs et al, 2008;Buchs et al, 2010), HP rocks (from García-Casco et al, 2006, 2008aIturralde-Vinent et al, 2008;Krebs et al, 2008) and CLIP material (from Geldmacher et al, 2003;Buchs et al, 2010;Lewis et al, 2011). given in Fig.…”

Composition and evolution of the Ancestral South Sandwich Arc: Implications for the flow of deep ocean water and mantle through the Drake Passage Gateway

“…An example is the Jurassic initiation of subduction in the Andes, where normal calc-alkaline arc volcanics formed without a near-trench volcanic terrane containing fore-arc basalts, boninites and related rocks (Romeuf et al, 1995). Similarly, in Central America, initiation of subduction beneath an oceanic plateau formed an arc without a boninitic precursor (Buchs et al, 2010). It is possible that the difference is that the latter examples involved subduction beneath thick lithosphere, which inhibited slab sinking and retreat.…”

The basaltic volcanism of the Dumisseau Formation in the Sierra de Bahoruco, SW Dominican Republic: a record of the mantle plume magmatism of the Caribbean Large Igneous Province

“…Norte y América del Sur desde el Jurásico (Mann, 1999;Pindell et al, 2005Pindell et al, , 2009. Sin embargo, el mecanismo de movimiento hacia el NE del plateau no es claro, especialmente con el inicio de la subducción en el arco de Costa Rica-Panamá hace unos 75 Ma (Campaniense Superior; Buchs et al, 2010). Usando "puntos calientes" como marco de referencia fijo, Duncan y Hargraves (1984) sugieren que los magmas del CLIP se produjeron por la fusión parcial dentro de la cabeza de la pluma inicial del punto caliente de Galápagos.…”