Jurassic and Early Cretaceous island arc volcanism, extension, and subsidence in the Coast Range of central Chile

Vergara, Marcos; Levi, Beatriz; Nyström, Jan Olov; Cancino, Alejandro

doi:10.1130/0016-7606(1995)107<1427:jaecia>2.3.co;2

Cited by 91 publications

(117 citation statements)

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“…The inner arc developed along the Coastal Cordillera of central Chile, erupted more than 2000 km 3 of acid and 9000 km 3 of basic volcanic rocks forming a 15-km-thick pile of alternately marine and continental deposits during the Jurassic and Early Cretaceous (Vergara et al 1995). The initial volcanics were more tholeiitic, changing to a more calcalkaline character in the younger rocks.…”

Section: Central Chile Basin (288-358s Lat)mentioning

confidence: 99%

“…The strong extensional conditions in Early Cretaceous times have been interpreted as being produced by intense asthenospheric upwelling in an 'aborted marginal basin' between 278 and 338S (Levi and Aguirre 1981;Ä berg et al 1984;Mpodozis and Ramos 1990). However, Charrier (1984) suggested the existence of an Early Cretaceous intra-arc basin in the present-day Coastal Cordillera, based on palaeogeographic considerations, criteria followed by subsequent interpretations (Ramos 1985(Ramos , 1988Charrier and Muñoz 1994;Vergara et al 1995;Ramos and Alemán 2000;Fuentes et al 2005).…”

Section: Central Chile Basin (288-358s Lat)mentioning

confidence: 99%

“…Another example is the Central Chile Basin with several kilometres of volcanic rocks (Vergara et al 1995). If the early Mesozoic palaeogeography of the Patagonian Andes is examined between 388 and 528S latitudes, it is evident an increase in the crustal attenuation in the back-arc basin to the south, being deeper as we move to the southernmost extreme .…”

Section: Rocas Verdes Basinmentioning

confidence: 99%

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

Ramos¹

2009

Geological Journal

230

139

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The analyses of the main parameters controlling the present Chile-type and Marianas-type tectonic settings developed along the eastern Pacific region show four different tectonic regimes: (1) a nearly neutral regime in the Oregon subduction zone; (2) major extensional regimes as the Nicaragua subduction zone developed in continental crust; (3) a Marianas setting in the Sandwich subduction zone with ocean floored back-arc basin with a unique west-dipping subduction zone and (4) the classic and dominant Chile-type under compression. The magmatic, structural and sedimentary behaviours of these four settings are discussed to understand the past tectonic regimes in the Mesozoic Andes based on their present geological and tectonic characteristics. The evaluation of the different parameters that governed the past and present tectonic regimes indicates that absolute motion of the upper plate relative to the hotspot frame and the consequent trench roll-back velocity are the first order parameters that control the deformation. Locally, the influences of the trench fill, linked to the dominant climate in the forearc, and the age of the subducted oceanic crust, have secondary roles. Ridge collisions of seismic and seismic oceanic ridges as well as fracture zone collisions have also a local outcome, and may produce an increase in coupling that reinforces compressional deformation. Local strain variations in the past and present Andes are not related with changes in the relative convergence rate, which is less important than the absolute motion relative to the Pacific hotspot frame, or changes in the thermal state of the upper plate. Changes in the slab dip, mainly those linked to steepening subduction zones, produce significant variations in the thermal state, that are important to generate extreme deformation in the foreland.

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Section: Central Chile Basin (288-358s Lat)mentioning

confidence: 99%

Section: Central Chile Basin (288-358s Lat)mentioning

confidence: 99%

Section: Rocas Verdes Basinmentioning

confidence: 99%

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

Ramos¹

2009

Geological Journal

230

139

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“…1a). In this segment, a well developed pattern of eastwarddecreasing age is observed, from Lower Jurassic to Lower Cretaceous granitoid complexes and Mesozoic volcanic-sedimentary sequences (e.g., Levi, 1973;Vergara et al, 1995;Parada et al, 1999). One striking feature of this area is the presence of NW-SE to WNW-ESE regional lineaments that crosscut the Coastal Ranges oblique to the current continental margin.…”

Section: Geological Settingmentioning

confidence: 84%

“…This deformation, mostly along the magmatic arc and the Atacama Fault Zone, was contemporaneous with the subsidence of Early Cretaceous basins in north and central Chile, in which large volumes of mantle-derived lavas accumulated (Vergara et al, 1995;Aguirre et al, 1999). Parada et al (1999) proposed that progressive depletion in the Sr and Nd isotopic signature of magmas towards MORB from the Jurassic to the Cretaceous was caused by an increased amount of lithosphere removal and crustal thinning related to extension.…”

Section: Geological Settingmentioning

confidence: 97%

Transtension y transpresion del Jurasico Medio-Superior al Cretacico Inferior durante la construccion del arco magmatico en Chile central: evidencia a partir de enjambres de diques maficos.

Creixell¹,

Parada²,

Morata³

et al. 2011

Andgeo

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AbstrACt. The Middle-Late Jurassic mafic dike swarms of central Chile between 33º and 33º45'S register the tectonic activity of the contemporaneous arc represented by the Coastal batholith. These dike swarms evidence alternate episodes of transtension and transpression across NW-striking structures, which controlled the construction of the magmatic arc. The Middle-Upper Jurassic and Lower Cretaceous mafic dike swarms in the Coastal range of central Chile has been studied through field observations, geochronology and AMS (anisotropy of magnetic susceptibility) to document the tectonic and magmatic evolution of the Jurassic-Cretaceous arc at this latitude. Middle to Upper Jurassic dike swarms (Concón and Cartagena mafic dike swarms) were emplaced between 163 and 157 Ma, along NW-SE to WNW-ESE-striking host fractures, registering a first stage of magma emplacement under sinistral transtension. During this stage, dikes acquired a fabric characterized by magnetic foliation clockwise oblique to dike trend and gently plunging lineations. This stage was followed rapidly by dike emplacement under sinistral transpression, with associated steeply plunging lineations in the dikes, reverse shear zones in the country rocks and local occurrence of horizontal mafic dikes. On the other hand, the Lower Cretaceous El Tabo Dike Swarm was emplaced along tensile fractures that do not register shear displacements along their walls. These dikes were emplaced at shallower crustal levels along tensile fractures.Within each dike swarm, differences in the tectonic style of emplacement correlates with changes in the geochemical composition of the dikes, suggesting a strong coupling between tectonics and nature of magma supplies in the arc. Finally, the current results show that the Mesozoic evolution of the Coastal Batholith of central Chile occurred in several stages of deformation and not under a simple scenario of extensional tectonics. This magmatism and deformation were strongly controlled by NW-to WNW-striking fractures. These structures are spatially correlated with regional-scale Cenozoic lineaments that are oblique to the orientation of the Andean orogen. We suggest that these lineaments are features inherited at least from Jurassic times. Middle-late Jurassic to early cretaceous transtension and transpression during arc building in central chile... rEsuMEn. transtensión y transpresión del Jurásico Medio-superior al Cretácico Inferior durante la construcción del arco magmático en Chile central: evidencia a partir de enjambres de diques máficos. Los enjambres de diques máficos del Jurásico Medio-Superior de Chile central entre los 33º y 33º45'S registran la actividad tectónica del arco contemporáneo representado por el batolito costero. Estos enjambres de diques evidencian episodios alternados de transtensión y transpresión a lo largo de estructuras de rumbo NW, las cuales controlaron la construcción del arco magmático. Los enjambres de diques máficos del Jurásico Medio-Superior y del Cretácico Inferior de la Cordillera de la Costa...

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