Transition From Collisional to Subduction‐Related Regimes: An Example From Neogene Panama‐Nazca‐South America Interactions

Abstract

A geological transect across the suture separating northwestern South America from the Panama Arc helps document the provenance and thermal history of both crustal domains and the suture zone. During middle Miocene, strata were being accumulated over the suture zone between the Panama Arc and the continental margin. Integrated provenance analyses of those middle Miocene strata show the presence of mixed sources that includes material derived from the two major crustal domains: the old northwestern South American orogens and the younger Panama Arc. Coeval moderately rapid exhumation of Upper Cretaceous to Paleogene sediments forming the reference continental margin is suggested from our inverse thermal modeling. Strata within the suture zone are intruded by ~12 Ma magmatic arc‐related plutons, marking the transition from a collisional orogen to a subduction‐related one. Renewed late Miocene to Pliocene acceleration of the exhumation rates is the consequence of a second tectonic pulse, which is likely to be triggered by the onset of a flat‐slab subduction of the Nazca plate underneath the northernmost Andes of Colombia, suggesting that late Miocene to Pliocene orogeny in the Northern Andes is controlled by at least two different tectonic mechanisms.

The emergent macrophyte Montrichardia linifera (Arruda) Schott (Alismatales: Araceae), a rekindled old friend from the Pacific Slope of lower Central America and western Colombia

“…On the other hand, there is a common geological origin of the Chocó (western Colombia) and Darién (eastern Panama) regions, as both are part of the Panama microplate, more specifically, the Chucunaque–Atrato geological blocks (Borrero et al , Montes et al , Cardona et al , León et al ). The collision of the Chucunaque – Atrato basin and its associated magmatic arc with South America began during the late Miocene circa 10 Mya, resulting in the collision that fused the Panamanian magmatic arc with the western Andes of Colombia along the Uramita suture (Montes et al , León et al ). The geological history of the Chocó suggests that the modern landscape was established during the early Pleistocene (~2.7 Mya) (Pérez‐Escobar et al ).…”

Synthesis of geological and comparative phylogeographic data point to climate, not mountain uplift, as driver of divergence across the Eastern Andean Cordillera

“…Political boundaries and the outline of Maracaibo Lake for reference. Most coarse-grained deposits at this time are sandy, from mostly fluvial and near-shore environments, and mark the segmentation of basins by rising mountain belts (Anderson et al, 2015; Barat et al, 2014; Borrero et al, 2012; Erikson et al, 2012; Farris et al, 2017; Gomez et al, 2005; Grosse, 1926; Guerrero, 1997; Hoorn et al, 2010; Leon et al, 2018; Montes et al, 2010; Moreno et al, 2015; Parnaud et al, 1995; Quiroz et al, 2010). Only two possible lowland passages are allowed at this time by these lithostratigraphic constraints and fish faunas: The Putumayo (Lundberg and Chernoff, 1992) to the South, and the Táchira corridor to the North.…”

Análisis de procedencia del registro sin-orogénico Maastrichtiano de la Formación Cimarrona, flanco occidental de la Cordillera Oriental colombiana

“…El registro de abanico deltaico de la Formación Cimarrona hace parte de sistemas terrígenos discontinuos, en los cuales lateralmente a pocos kilómetros se acumularon sistemas carbonatados y de fondos marinos lodosos (Guerrero et al, 2000;Gómez et al, 2003;Bayona, 2018). Esta configuración contrasta con el aparente carácter continuo de la sedimentación clástica contemporánea en las cuencas sedimentarias occidentales que hoy hacen parte la Cordillera Occidental colombiana (González, 2001;Nivia, 2001;León et al, 2018), sugiriendo por lo tanto que el crecimiento cordillerano oriental de los Andes del Norte durante el inicio de la orogenia Andina está marcado por diferentes bloques emergidos (Bayona, 2018), los cuales habrían sido erosionados y sepultados probablemente en el Valle del Magdalena (Caballero et al, 2013), y podrían tener características litoestratigráficas semejantes a las presentes en la Cordillera Central. Por lo tanto, se sugiere que el relleno de la Formación Cimarrona podría estar relacionado a la denudación de los niveles corticales superiores de un dominio semejante a la Cordillera Central o un alto de basamento expuesto en el Valle del Magdalena los cuales tendrían las mismas características geológicas (Figura 9).…”