The Pali Aike Volcanic Field, Patagonia: slab-window magmatism near the tip of South America

D’Orazio, Massimo; Agostini, Samuele; Mazzarini, Francesco; Innocenti, Fabrizio; Manetti, Piero; Haller, Miguel J.; Lahsen, Alfredo

doi:10.1016/s0040-1951(00)00082-2

Cited by 147 publications

(104 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…That a slab window did form is consistent with the widespread Miocene alkaline volcanic rocks (Ramos and Kay, 1992;D'Orazio et al, 2000;2001;2004;Gorring et al, 1997). The slab window is mapped approximately in Fig.…”

Section: Collisions At the Chile Trench: 15 Ma-presentsupporting

confidence: 53%

Animated tectonic reconstruction of the Southern Pacific and alkaline volcanism at its convergent margins since Eocene times

2009

View full text Add to dashboard Cite

An animated reconstruction shows South Pacific plate kinematics, in the reference frame of West Antarctica, between 55 Ma and the presentday. The ocean floor in the region formed due to seafloor spreading between the Antarctic, Pacific, Phoenix and Nazca plates (a plate formed by fragmentation of the Farallon plate early in Oligocene times). The Pacific-Antarctic Ridge remained fairly stable throughout this time, migrating relatively northwestwards, by various mechanisms, behind the rapidly-moving Pacific plate. The Nazca and Phoenix plates also moved quickly, but relatively towards the east or southeast, and were subducted in these directions beneath the South American and Antarctic plates. Segments of spreading centres forming at the trailing edges of the Nazca and Phoenix plates periodically collided with these subduction zones, resulting in the total destruction of the Nazca-Phoenix spreading centre and the partial destruction of the Nazca-Antarctica spreading centre (the Chile Ridge) and Antarctic-Phoenix Ridge, which ceased to operate shortly before its northeasternmost three segments could collide with the Antarctic margin. Following collision of segments of the Chile Ridge, parts of the Antarctic plate underwent subduction at the Chile Trench. After these collisions, slab windows should have formed beneath both the South American and Antarctic convergent margins, and the animation shows occurrences of alkaline volcanism that have been, or can newly be, related to them. Further occurrences of alkali basalts, at the margins of the Powell Basin and, more speculatively, James Ross Island, can be related to the formation of a slab window beneath them following the collision of segments of the South America-Antarctica spreading centre in the northwest Weddell Sea.

show abstract

Section: Collisions At the Chile Trench: 15 Ma-presentsupporting

confidence: 53%

Animated tectonic reconstruction of the Southern Pacific and alkaline volcanism at its convergent margins since Eocene times

2009

View full text Add to dashboard Cite

show abstract

“…The PAVF eruptive products are alkaline and typically olivine-bearing, ranging from basalts to basanites, and have trace element signatures similar to those of ocean island basalts (OIB) (Skewes and Stern, 1979;D'Orazio et al, 2000). No "subduction" signature is detectable in the geochemical composition of the erupted products, leading to slab-window models for the PAVF volcanism (e.g., D'Orazio et al, 2000;Wang et al, 2008), in common with other volcanic fields further north (e.g., Ramos and Kay, 1992). However, some workers now prefer a slab rollback model for back-arc volcanism in this region (e.g., Muñoz et al, 2000;de Ignacio et al, 2001).…”

Section: Geological Context 21 Tectonic Settingmentioning

confidence: 99%

“…The volcanic field has been informally divided into three stratigraphic units, U1 to U3, by D'Orazio et al (2000). The oldest and most extensive unit, U1, consists of tabular lava flows which collectively form a plateau.…”

Section: Pavf Stratigraphymentioning

confidence: 99%

Influence of the substrate on maar–diatreme volcanoes — An example of a mixed setting from the Pali Aike volcanic field, Argentina

Ross

Delpit

Haller

et al. 2011

Journal of Volcanology and Geothermal Research

101

View full text Add to dashboard Cite

The morphologic parameters, pyroclastic deposits and evolution of maar-diatreme volcanoes are affected by the type of environment in which they are emplaced. End-member cases are a hard substrate (rocks) and a soft substrate (unconsolidated volcaniclastic or sedimentary deposits). In this paper, we present an example of a volcanic complex emplaced in a mixed hard-soft setting from the Pali Aike volcanic field (PAVF) near the Argentina-Chile border. The PlioPleistocene PAVF is an alkaline, mafic, back-arc monogenetic field which contains over 100 phreatomagmatic volcanoes. The studied volcanic complex contains two large coalescent maars overlain by scoria and spatter. The 1.4x1.3 km East Maar has better exposures than the shallower, 1.9 km-wide West Maar and seems to have been less modified by post-eruptive processes. The tephra rim of the East Maar was studied in detail and we infer it was produced mostly by base surges from phreatomagmatic eruption columns, with rare instances of intercalated scoria fall layers. Based on regional information, the general pre-maar stratigraphy is dominated by sedimentary and volcaniclastic rocks of the Magallanes Basin, including a thick poorly consolidated upper unit dating from the Miocene. These are overlain by Plio-Pleistocene fluvio-glacial deposits and PAVF lavas, some of which are exposed in the East Maar just below the phreatomagmatic deposits. All of these units are represented as lithic clasts in the tephra rim of the East Maar, the most abundant being the clasts from the earlier basaltic lavas and rock fragments derived from the glacial deposits. There is no specific evidence for a deep diatreme under the East Maar, and in this particular case, the mixed environment seems to have produced a maar-diatreme volcano typical of a soft substrate.

show abstract

“…unidad volcánica nº2 identificada por D' Orazio et al (2000), presentando una edad de 0.31 ± 0.03 m.a (Meglioli 1992). Las prospecciones realizadas a lo largo de Cerro de los Frailes mostraron evidencias de ocupaciones humanas en la mayoría de los conos volcánicos (Charlin 2009a).…”

Section: Las Muestrasunclassified

Obsidiana gris porfírica calco-alcalina del volcán Chaitén en sitios arqueológicos al sur del río Santa Cruz, Patagonoa meridional

et al. 2012

View full text Add to dashboard Cite

The Pali Aike Volcanic Field, Patagonia: slab-window magmatism near the tip of South America

Cited by 147 publications

References 52 publications

Animated tectonic reconstruction of the Southern Pacific and alkaline volcanism at its convergent margins since Eocene times

Animated tectonic reconstruction of the Southern Pacific and alkaline volcanism at its convergent margins since Eocene times

Influence of the substrate on maar–diatreme volcanoes — An example of a mixed setting from the Pali Aike volcanic field, Argentina

Obsidiana gris porfírica calco-alcalina del volcán Chaitén en sitios arqueológicos al sur del río Santa Cruz, Patagonoa meridional

Contact Info

Product

Resources

About