The tectonic regime along the Andes: Present‐day and Mesozoic regimes

Ramos, Víctor A.

doi:10.1002/gj.1193

Cited by 230 publications

(165 citation statements)

References 160 publications

(207 reference statements)

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“…The western Cordillera comprises the central volcanic arc region of the Peruvian Andes with altitudes of up to 6768 m a.s.l., where currently active volcanoes south of 14 • S of latitude are related to a steep slab subduction. Conversely, Cenozoic volcanoes in the central and northern Peruvian arc have been extinct since c. 11 Ma due to a flat slab subduction, which inhibited magma upwelling from the asthenosphere (Ramos, 2010).…”

Section: Geologic and Tectonic Settingmentioning

confidence: 99%

Possible threshold controls on sediment grain properties of Peruvian coastal river basins

2017

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Abstract. To determine possible controls on sediment grain properties, 21 coastal rivers located along the entire western Peruvian margin were analysed. This represents one of the largest grain size dataset that has been collected over a large area. Modern gravel beds were sampled along a north-south transect on the western side of the Peruvian Andes where the rivers cross the tip of the mountain range, and at each site the long a axis and the intermediate b axis of about 500 pebbles were measured. Morphometric properties of each drainage basin, sediment and water discharge, together with flow shear stresses, were determined and compared against measured grain properties. Pebble size data show that the values for the D 50 are nearly constant and range between 2 and 3 cm, while the values of the D 96 range between 6 and 12 cm. The ratios between the intermediate and the long axis range from 0.67 to 0.74. Linear correlations between all grain size percentiles and water shear stresses, mean basin denudation rates, mean basin slopes and basin sizes are small to non-existent. However, exceptionally large D 50 values of 4-6 cm were measured for basins situated between 11-12 and 16-17 • S latitude where hillslope gradients are steeper than on average or where mean annual stream flows exceed the average values of the western Peruvian streams by a factor of 2. We suggest that the generally uniform grain size pattern has been perturbed where either mean basin slopes or water fluxes exceed threshold conditions.

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Section: Geologic and Tectonic Settingmentioning

confidence: 99%

Possible threshold controls on sediment grain properties of Peruvian coastal river basins

2017

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“…It appears then that during the Late Cretaceous-Early Tertiary, large crystalline terranes, containing Jurassic-Cretaceous magmatic arcs, were emplaced upon the entire west coast of South America, and not necessarily only during the Paleozoic as commonly hypothesized (Vaughan et al 2005;Ramos 2008Ramos , 2009Ramos , 2010a. In our alternative model, eastward-vergent Late Cretaceous-Early Tertiary fold-thrust belts and associated eastwardly migrating foredeep basins developed on cratonic South America nearly synchronously with collision of a composite arc-bearing ribbon continent.…”

Section: Regional Considerationsmentioning

confidence: 64%

“…The concurrence of two periods of slab-failure magmatism and a period of subduction-related plutonism in the same linear trend over such a long period of time is most likely related to the narrow width of the HuarmeyCoastal batholith-Arequipa block and its history of subduction and collision. It should serve as a cautionary tale for those geologists who argue that arcs oscillate back and forth between compression and extension simply due to slab dip, obliquity, or convergence rate (Ducea 2001;Ramos 2009Ramos , 2010aDeCelles et al 2009;Paterson et al 2012b). In the case of the Arequipa terrane the variations are due to complex plate interactions that led to three periods of subduction, two collisions, and two periods of slab-failure magmatism.…”

Section: Discussionmentioning

confidence: 99%

“…In the current paradigm, from the Gulf of Guayaquil southward, a long-lived arc complex formed within and upon the continental lip above the eastward-dipping subduction zone (Pitcher 1993;Jaillard and Soler 1996). In this hypothesis, while subduction remained easterly at least since the Jurassic, variable stresses within the margin, generally attributed to changes in slab dip and obliquity, led to arc migration and shut-down as well as periods of extension, which formed basins, and periods of compression, which created fold-thrust belts (for example Kay and Mpodozis 2002;Ramos and Folguera 2005;Ramos and Kay 2006;Mosquera and Ramos 2006;Ramos 2009Ramos , 2010a.…”

Section: Introductionmentioning

confidence: 99%

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Arc and Slab-Failure Magmatism in Cordilleran Batholiths I – The Cretaceous Coastal Batholith of Peru and its Role in South American Orogenesis and Hemispheric Subduction Flip

Hildebrand¹,

Whalen

2014

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We examined the temporal and spatial relations of rock units within the Western Cordillera of Peru where two Cretaceous basins, the Huarmey-Cañete and the West Peruvian Trough, were considered by previous workers to represent western and eastern parts respectively of the same marginal basin. The Huarmey-Cañete Trough, which sits on Mesoproterozoic basement of the Arequipa block, was filled with up to 9 km of Tithonian to Albian tholeiitic–calc-alkaline volcanic and volcaniclastic rocks. It shoaled to subaerial eastward. At 105–101 Ma the rocks were tightly folded and intruded during and just after the deformation by a suite of 103 ± 2 Ma mafic intrusions, and later in the interval 94–82 Ma by probable subduction-related plutons of the Coastal batholith. The West Peruvian Trough, which sits on Paleozoic metamorphic basement, comprised a west-facing siliciclastic-carbonate platform and adjacent basin filled with up to 5 km of sandstone, shale, marl and thinly bedded limestone deposited continuously throughout the Cretaceous. Rocks of the West Peruvian Trough were detached from their basement, folded and thrust eastward during the Late Cretaceous–Early Tertiary. Because the facies and facing directions of the two basins are incompatible, and their development and subjacent basements also distinct, the two basins could not have developed adjacent to one another. Based on thickness, composition and magmatic style, we interpret the magmatism of the Huarmey-Cañete Trough to represent a magmatic arc that shut down at about 105 Ma when the arc collided with an unknown terrane. We relate subsequent magmatism of the early 103 ± 2 Ma syntectonic mafic intrusions and dyke swarms to slab failure. The Huarmey-Cañete-Coastal batholithic block and its Mesoproterozoic basement remained offshore until 77 ± 5 Ma when it collided with, and was emplaced upon, the partially subducted western margin of South America to form the east-vergent Marañon fold–thrust belt. A major pulse of 73–62 Ma plutonism and dyke emplacement followed terminal collision and is interpreted to have been related to slab failure of the west-dipping South American lithosphere. Magmatism, 53 Ma and younger, followed terminal collision and was generated by eastward subduction of Pacific oceanic lithosphere beneath South America. Similar spatial and temporal relations exist over the length of both Americas and represent the terminal collision of an arc-bearing ribbon continent with the Americas during the Late Cretaceous–Early Tertiary Laramide event. It thus separated long-standing westward subduction from the younger period of eastward subduction characteristic of today. We speculate that the Cordilleran Ribbon Continent formed during the Mesozoic over a major zone of downwelling between Tuzo and Jason along the boundary of Panthalassic and Pacific oceanic plates.SOMMAIRENous avons étudié les relations spatiales et temporales des unités de roches dans la portion ouest de la Cordillère du Pérou, où deux bassins crétacés, la fosse d’accumulation de Huarmey-Cañete et la fosse d’accumulation péruvienne de l’ouest, ont été perçues par des auteurs précédents comme les portions ouest et est d’un même bassin de marge. La fosse de Huarmey-Cañete, qui repose sur le socle mésoprotérozoïque du bloc d’Arequipa, a été comblée par des couches de roches volcaniques tholéitiques – calco-alcalines de l’Albien au Thithonien atteignant 9 km d’épaisseur. Vers l’est, l’ensemble a fini par former des hauts fonds. Vers 105 à 101 Ma, les roches ont été plissées fortement puis recoupées par une suite d’intrusions vers 103 ± 2 Ma, durant et juste après la déformation, et plus tard dans l’intervalle 94 – 82 Ma, probablement par des plutons de subduction du batholite côtier. Quant à la fosse d’accumulation péruvienne de l’ouest, elle repose sur un socle métamorphique paléozoïque, et elle est constituée d’une plateforme silicoclastique – carbonate à pente ouest et d’un bassin contigu comblé par des grès, des schistes, des marnes et des calcaires finement laminés atteignant 5 km d’épaisseur et qui se sont déposés en continu durant tout le Crétacé. Les roches de la fosse d’accumulation péruvienne de l’ouest ont été décollées de leur socle, plissées et charriées vers l’est durant la fin du Crétacé et le début du Tertiaire. Parce que les facies et les profondeurs de sédimentation de ces deux fosses d’accumulation dont incompatibles, et que leur développement et leur socle sont différents, ces deux fosses ne peuvent pas s’être développées côte à côte. À cause de l’épaisseur accumulée, de sa composition et du style de son magmatisme, nous pensons que la fosse d’accumulation de Huarmey-Cañete représente un arc magmatique qui s’est éteinte vers 105 Ma, lorsque l’arc est entré en collision avec un terrane inconnu. Nous pensons que le magmatisme subséquent aux premières intrusions mafiques syntectoniques et aux réseaux de dykes de 103 ± 2 Ma sont à mettre au compte d’une rupture de plaque. Le bloc Huarmey-Cañete-batholitique côtier et son socle mésoprotérozoïque sont demeurés au large jusqu’à 77 ± 5 Ma, moment où il est entré en collision et a été poussé par-dessus la marge ouest sud-américaine partiellement subduite, pour ainsi former la zone de chevauchement de vergence est de Marañon. Nous croyons que la séquence majeure de plutonisme et d’intrusion de dykes qui a succédé à la collision finale à 73–62 Ma doit être reliée à une rupture de la plaque lithosphérique sud-américaine à pendage ouest. Le magmatisme de 53 Ma et plus récent qui a succédé à la collision finale, a été généré par la subduction vers l’est de la lithosphère océanique du Pacifique sous l’Amérique du Sud. Des relations temporelles et spatiales similaires qui existent tout le long des deux Amériques représentent la collision terminale d’un ruban continental d’arcs avec les Amériques durant la phase tectonique laramienne de la fin du Crétacé–début du Tertiaire. Elle a donc séparé la subduction vers l’ouest de longue date de la période de subduction vers l’est plus jeune caractérisant la situation actuelle. Nous considérons que le ruban continental de la Cordillère s’est constitué durant le Mésozoïque au-dessus d’une zone majeure de convection descendante entre Tuzo et Jason, le long de la limite entre les plaques océaniques Panthalassique et Pacifique.

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“…Estas evidencias sugieren que durante la etapa de subsidencia termal jurásico-cretácica (e.g., Legarreta y Uliana, 1991;Howell et al, 2005;Ramos y Folguera, 2005;Ramos, 2010) existieron controles tectónicos sobre la evolución de las sucesiones sedimentarias. En este sentido, la facies de brechas intraclásticas que aparece en la base de la Formación Vaca Muerta se relaciona probablemente con la actividad sísmica del margen andino, antes que con factores autocíclicos del propio sistema depositacional.…”

Section: Discussionunclassified

Sedimentology and stratigraphy of the Vaca Muerta Formation in the Cerro Domuyo area, Northern Neuquén, Argentina.

Kietzmann

Vennari

2013

andgeo

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RESUMEN. Los depósitos de la Formación Vaca Muerta en el área del cerro Domuyo muestran una interesante intercalación de depósitos con paleocorrientes opuestas. La unidad está representada por facies de cuenca y rampa externa con dirección de progradación hacia el oeste. Sin embargo, en su parte media se intercalan depósitos de talud, con desarrollo de deslizamientos sinsedimentarios hacia el NE, que pueden asignarse al Miembro Huncal. Este intervalo se compone de facies carbonáticas que probablemente se asocien con el desarrollo de un talud relacionado con una plataforma carbonática o una rampa distalmente profundizada. A partir de la fauna de amonites reconocida, la Formación Vaca Muerta se extiende desde el Tithoniano temprano hasta el Berriasiano tardío, aunque podría alcanzar el Valanginiano temprano. El Miembro Huncal contiene representantes de la Biozona de Substeueroceras koeneni (Tithoniano tardío), por lo que su edad sería más antigua que la propuesta en la localidad tipo y permitiría su correlación con las unidades aflorantes en el territorio chileno. ABSTRACT. Sedimentology and stratigraphy of the Vaca Muerta Formation in the Cerro Domuyo area, Northern Neuquén, Argentina. The Vaca Muerta Formation in the Cerro Domuyo area shows an interesting intercalation of facies with opposite paleocurrents. The unit is represented by outer ramp to basinal facies with a westward direction of progradation. However, in its middle section, slope deposits correlatable with the Huncal Member, are intercalated with slumped strata verging NE. This interval is composed of carbonate facies and it is probably associated with the development of a slope related to a carbonate platform or a distally steepened carbonate ramp. Based on the ammonoid fauna, the age of the Vaca Muerta Formation ranges from the early Tithonian to the late Berriasian, but it could also reach the early Valanginian. The Huncal Member yields representatives of the Substeueroceras koeneni Biozone (late Tithonian), hence its age is older than that proposed in its type locality allowing its correlation with units exposed in the Chilean territory.

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The tectonic regime along the Andes: Present‐day and Mesozoic regimes

Cited by 230 publications

References 160 publications

Possible threshold controls on sediment grain properties of Peruvian coastal river basins

Possible threshold controls on sediment grain properties of Peruvian coastal river basins

Arc and Slab-Failure Magmatism in Cordilleran Batholiths I – The Cretaceous Coastal Batholith of Peru and its Role in South American Orogenesis and Hemispheric Subduction Flip

Sedimentology and stratigraphy of the Vaca Muerta Formation in the Cerro Domuyo area, Northern Neuquén, Argentina.

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