Geochemical variations in Cenozoic back-arc basalts at the border of La Pampa and Mendoza provinces, Argentina

Bertotto, Gustavo Walter; Cingolani, Carlos Alberto; Bjerg, Ernesto

doi:10.1016/j.jsames.2009.04.008

Cited by 33 publications

(15 citation statements)

References 23 publications

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“…The issue of crustal contamination in the PMVF is not clear as there are no crustal Sr-isotopic values for this area (Espanon et al, 2014). The Sr isotope values for the Pampas Onduladas flow are in agreement with those previously presented for the PMVF (Pasquarè et al, 2008;Bertotto et al, 2009;Hernando et al, 2012;Jacques et al, 2013;Søager et al, 2013;Espanon et al, 2014).…”

Section: Petrogenesis Of the Pampas Onduladas Flowsupporting

confidence: 86%

Geochronological, morphometric and geochemical constraints on the Pampas Onduladas long basaltic flow (Payún Matrú Volcanic Field, Mendoza, Argentina)

Espanon

Chivas

Phillips

et al. 2014

Journal of Volcanology and Geothermal Research

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The Pampas Onduladas flow in southern Mendoza, Argentina, is one of the four longest Quaternary basaltic flows on Earth. Such flows (> 100 km) are relatively rare on Earth as they require special conditions in order to travel long distances and there are no recent analogues. Favourable conditions include: a gentle topographic slope, an insulation process to preserve the melt at high temperature, and a large volume of lava with relatively low viscosity. This study investigates the rheological and geochemical characteristics of the ~ 170 km long Pampas Onduladas flow, assessing conditions that facilitated its exceptional length. The study also reports the first geochronological results for the Pampas Onduladas flow. 40Ar/39Ar step-heating analyses of groundmass reveal an eruption age of 373 ± 10 ka (2σ), making the Pampas Onduladas flow the oldest Quaternary long flow. The methods used to assess the rheological properties include the application of several GIS tools to a digital elevation model (DEM) to determine the length, width, thickness, volume and topographic slope of the flow as well as algorithms to determine its density, viscosity and temperature. The slope of the Pampas Onduladas flow determined from the initial part of the flow on the eastern side of La Carbonilla Fracture to its end point in the province of La Pampa is 0.84% (0.29°), the steepest substrate amongst long Quaternary flows. The rheological properties, such as density viscosity and temperature from the Pampas Onduladas flow are similar to values reported for other long Quaternary flows. However, the minimum volume calculated is relatively low for its length compared with other long Quaternary flows. Therefore, the extension of the Pampas Onduladas flow was probably controlled by a steep slope, combined with an insulating mechanism, which helped in providing optimal conditions for a travel length of almost 170 km.

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Section: Petrogenesis Of the Pampas Onduladas Flowsupporting

confidence: 86%

Geochronological, morphometric and geochemical constraints on the Pampas Onduladas long basaltic flow (Payún Matrú Volcanic Field, Mendoza, Argentina)

Espanon

Chivas

Phillips

et al. 2014

Journal of Volcanology and Geothermal Research

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“…2008; Mazzarini et al, 2008;Folguera et al, 2009). Geochemically, rocks range from basalts to andesites, with arc to intraplate signatures (e.g., Kay et al, 2006;Ramos and Kay, 2006;Bertotto et al, 2009). Payenia has been divided into several volcanic fields according to their geographical and geochemical characteristics (Bermúdez et al, 1993;Ramos and Folguera, 2011;Gudnason et al, 2012).…”

Section: Payenia Volcanic Provincementioning

confidence: 99%

Volcanology and inflation structures of an extensive basaltic lava flow in the Payenia Volcanic Province, extra-Andean back arc of Argentina

Bernardi

Bertotto

Ponce

et al. 2019

andgeo

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The El Puesto lava flow is located in the Payenia Volcanic Province (central-western Argentina), has a length of 70 km and is Middle Pleistocene in age (0.200±0.027 Ma). The flow shows a P-type pahoehoe structure and exhibits several inflation structures, mainly tumuli and also inflation ridges and lava rises. Lava rise pits and radial or annular clefts are common features associated with inflation structures. The gentle slope on which the flow moved (≈0.5°) allowed the lateral coalescence of lobes at the flow front and the development of an external rigid crust that insulated the liquid core. Lava tunnels are frequent and the lava tunnel named “Cueva de Halada” which is located at its medium portion is the best example of a drainage master tube which formed from the cooling of the crust around a stable inflated flow. Tumuli alignments and long inflation ridges reveal the existence of larger tunnels within the flow. Inflation structures may occur in high concentration belts that converge on a single main belt which is assigned to an anastomosed network of internal flow pathways within the main lava body. The development of inflation structures and lava tunnels require low to moderate effusion rates. An average lava supply rate of 1.8x10-4 m3/s and an inflation time of about 15 days were estimated for an average tumulus of this flow. A high and sustained supply of low viscosity lava (η’=1550 - 483 Pa s) was inferred that initially generated a sheet flow of great areal extension. The reduction in effusion rates could then allowed the development of tunnels that carried lava to the distal fronts, generating localized inflation phenomena throughout the lava flow.

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“…The backarc (BA) domain, from 100 km to km behind the volcanic front is known as 124 the Payenia volcanic field (Munoz andStern, 1988, Stern, 1989) Patagonian mafic volcanic province (Kay et al, 2004, Bertotto et al, 2009, while others keep it 127 separate for geological and tectonic reasons (Ramos and Folguera, 2011). The Payenia volcanic 128 field covers more than 40,000 km 2 between 34°S-38°S with an estimated volume of 8400 km 3 erupted from more than 800 centers in the last 2 Ma.…”

Section: Geological Settingmentioning

confidence: 99%

Across-arc geochemical variations in the Southern Volcanic Zone, Chile (34.5–38.0°S): Constraints on mantle wedge and slab input compositions

Jacques¹,

Hoernle

Gill

et al. 2013

Geochimica et Cosmochimica Acta

108

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31 32Crustal assimilation (e.g. Hildreth and Moorbath, 1988) and/or subduction erosion (e.g. Stern, 33 1991; Kay et al., 2005) are believed to control the geochemical variations along the northern 34 portion of the Chilean Southern Volcanic Zone. In order to evaluate these hypotheses, we present 35 a comprehensive geochemical data set (major and trace elements and O-Sr-Nd-Hf-Pb isotopes) 36 from Holocene primarily olivine-bearing volcanic rocks across the arc between 34.5-38.0°S, 37 including volcanic front centers from Tinguiririca to Callaqui, the rear arc centers of Infernillo 38Volcanic Field, Laguna del Maule and Copahue, and extending 300 km into the backarc. We also 39 present an equivalent data set for Chile Trench sediments outboard of this profile.

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Geochemical variations in Cenozoic back-arc basalts at the border of La Pampa and Mendoza provinces, Argentina

Cited by 33 publications

References 23 publications

Geochronological, morphometric and geochemical constraints on the Pampas Onduladas long basaltic flow (Payún Matrú Volcanic Field, Mendoza, Argentina)

Geochronological, morphometric and geochemical constraints on the Pampas Onduladas long basaltic flow (Payún Matrú Volcanic Field, Mendoza, Argentina)

Volcanology and inflation structures of an extensive basaltic lava flow in the Payenia Volcanic Province, extra-Andean back arc of Argentina

Across-arc geochemical variations in the Southern Volcanic Zone, Chile (34.5–38.0°S): Constraints on mantle wedge and slab input compositions

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