From incipient island arc to doubly‐vergent orogen: A review of geodynamic models and sedimentary basin‐fills of southern Central America

Abstract

Southern Central America is a Late Mesozoic/Cenozoic island arc that evolved in response to the subduction of the Farallón Plate beneath the Caribbean Plate in the Late Cretaceous and, from the Oligocene, the Cocos and Nazca Plates. Southern Central America is one of the best studied convergent margins in the world. The aim of this paper is to review the sedimentary and structural evolution of arc‐related sedimentary basins in southern Central America, and to show how the arc developed from a pre‐extensional intra‐oceanic island arc into a doubly‐vergent, subduction orogen. The Cenozoic sedimentary history of southern Central America is placed into the plate tectonic context of existing Caribbean Plate models. From regional basin analysis, the evolution of the southern Central American island arc is subdivided into three phases: (i) non‐extensional stage during the Campanian; (ii) extensional phase during the Maastrichtian‐Oligocene with rapid basin subsidence and deposition of arc‐related, clastic sediments; and (iii) doubly‐vergent, compressional arc phase along the 280 km long southern Costa Rican arc segment related to either oblique subduction of the Nazca plate, west‐to‐east passage of the Nazca–Cocos–Caribbean triple junction, or the subduction of rough oceanic crust of the Cocos Plate. The Pleistocene subduction of the Cocos Ridge contributed to the contraction but was not the primary driver. The architecture of the arc‐related sedimentary basin‐fills has been controlled by four factors: (i) subsidence caused by tectonic mechanisms, linked to the angle and morphology of the incoming plate, as shown by the fact that subduction of aseismic ridges and slab segments with rough crust were important drivers for subduction erosion, controlling the shape of forearc and trench‐slope basins, the lifespan of sedimentary basins, and the subsidence and uplift patterns; (ii) subsidence caused by slab rollback and resulting trench retreat; (iii) eustatic sea‐level changes; and (iv) sediment dispersal systems.

Volcanic contribution to emergence of Central Panama in the Early Miocene

“…However, the timing of this collision and its control on the emergence of the isthmus remain uncertain, as exemplified by proposed ages for initial collision that range from the Late Cretaceous 54 to the Eocene 14,36 and Neogene 44,46,53 . In addition, different segments of the Panama volcanic arc have been affected by complex, diachronous uplift events due to local and regional tectonic processes that are not related to collision with South America (e.g., seamount collisions and changing subduction dynamics) 10,12,28,55,56 . Clearly, a large range of tectonic processes could have contributed to the emergence of the Isthmus.…”

Volcanic shutdown of the Panama Canal area following breakup of the Farallon plate

“…Although the cause(s) of the migration of volcanic fronts in Panama between ca. 40 and 34 Ma remains poorly understood, it can be noted that this migration occurred following: (i) regional uplift event(s) in the Eocene (Mann and Kolarsky, 1995;Buchs et al, 2011;Montes et al, 2012a;Barat et al, 2014;Ramirez et al, 2016;Brandes and Winsemann, 2018); and (ii) initiation of oroclinal bending and associated development of the central Panamanian fault zone (Montes et al, 2012b) (Fig. 2).…”

“…2). This suggests that relocation of magmatism in Panama resulted from a combination of changes in subduction dynamics possibly due to a reorganisation of plate tectonics in the Pacific (Brandes and Winsemann, 2018;Buchs et al, 2011), and collision of the Panama volcanic arc with South America in the Eocene (Barat et al, 2014). Another hypothesis that could explain reorganisation of arc fronts in the Late Eocene is the collisio of a i de tor e.g., o ea i plateau ca.…”

Long-term non-erosive nature of the south Costa Rican margin supported by arc-derived sediments accreted in the Osa Mélange

“…However, it is interesting to note that the emplacement of this unit in the Late Eocene followed, or was partly synchronous to, major geological changes in Costa Rica and Panama (Buchs et al, 2011b). At this time, volcanic fronts were displaced up to ∼100 km in Panama (Wegner et al, 2011), and major unconformities developed in forearc and back-arc basins in Costa Rica and Panama (Kolarsky et al, 1995;Brandes and Winsemann, 2018). This shows that important changes occurred in the dynamics of subduction at this time, which could have been caused by plate re-organisation in the Pacific (Buchs et al, 2011b) and/or collision of Panama with South America (Montes et al, 2012).…”

“…Although the long-term non-erosive behaviour of the south Costa Rican margin was possibly punctuated by short periods of tectonic erosion (e.g., Buchs et al, 2011b;Vannucchi et al, 2013), subsidence patterns along the forearc are unlikely to offer a reliable indication of erosion. The geological record, neotectonic constraints and the present-day morphology of the south Central American margin provide numerous examples of spatially-and temporarily-restricted phases of uplift and subsidence in response to the collision of seamounts and other topographic highs on the subducting Cocos and Nazca Plates (Corrigan et al, 1990;Fisher et al, 1998;Sak et al, 2009;Buchs et al, 2011b;Morell, 2016;Andji´c et al, 2018;Brandes and Winsemann, 2018;Morell et al, 2019). Events of uplift and subsidence along the forearc have most likely been abundant during the longterm history of the forearc considering that, since inception of the subduction zone in the Late Cretaceous (Buchs et al, 2010;Wegner et al, 2011;Andji´c et al, 2019), the margin has continuously been impacted by the arrival of seamounts formed at the Galapagos Hotspot (Hoernle et al, 2002).…”