About this title - Volcanism in Antarctica: 200 Million Years of Subduction, Rifting and Continental Break-up

10.1144/m55 ◽  
2021 ◽  
Vol 55 (1) ◽  
pp. NP-NP
Keyword(s):  
Lava Lake ◽  
Rift System ◽  
West Antarctic ◽  
Continental Arc ◽  
Lithospheric Extension ◽  
Break Up ◽  
Felsic Volcanic ◽  
Mafic Volcanism ◽  
Back Arc ◽  
West Antarctic Rift System

This memoir is the first to review all of Antarctica's volcanism between 200 million years ago and the Present. The region is still volcanically active. The volume is an amalgamation of in-depth syntheses, which are presented within distinctly different tectonic settings. Each is described in terms of (1) the volcanology and eruptive palaeoenvironments; (2) petrology and origin of magma; and (3) active volcanism, including tephrochronology. Important volcanic episodes include: astonishingly voluminous mafic and felsic volcanic deposits associated with the Jurassic break-up of Gondwana; the construction and progressive demise of a major Jurassic to Present continental arc, including back-arc alkaline basalts and volcanism in a young ensialic marginal basin; Miocene to Pleistocene mafic volcanism associated with post-subduction slab-window formation; numerous Neogene alkaline volcanoes, including the massive Erebus volcano and its persistent phonolitic lava lake, that are widely distributed within and adjacent to one of the world's major zones of lithospheric extension (the West Antarctic Rift System); and very young ultrapotassic volcanism erupted subglacially and forming a world-wide type example (Gaussberg).

GEODYNAMIC MODELS FAVOR PASSIVE RIFTING OF THE WEST ANTARCTIC RIFT SYSTEM

2018 ◽  
Author(s):  
Dennis L. Harry ◽  
◽  
Sumant Jha
Keyword(s):  
Rift System ◽  
The West ◽  
West Antarctic ◽  
Geodynamic Models ◽  
West Antarctic Rift System ◽  
West Antarctic Rift

scholarly journals Lithofacies and eruptive conditions of the southernmost volcanoes in the world (87° S)

2021 ◽  
Vol 83 (8) ◽  
Author(s):  
J. L. Smellie ◽  
K. S. Panter
Keyword(s):  
Volcanic Edifice ◽  
Rift System ◽  
The West ◽  
Basal Diameter ◽  
Monogenetic Volcano ◽  
West Antarctic ◽  
Ice Stream ◽  
Free Environment ◽  
West Antarctic Rift System ◽  
West Antarctic Rift

AbstractNeogene volcanic centres are uncommon in the Transantarctic Mountains but at least three basaltic examples occur within 300 km of South Pole, above 2200 m asl and inland of the margin of the West Antarctic Rift System. They are the southernmost volcanoes on Earth and have yielded Early—mid Miocene isotopic ages. Two of the centres, at Mt Early and Sheridan Bluff, have been examined. The centre at Mt Early is unequivocally glaciovolcanic. It formed a tall monogenetic volcanic edifice at least 1 km high and > 1.5 km in diameter. It erupted under significantly thicker-than-modern ice, which was probably a fast-moving ice stream at the eruptive site and resulted in a distinctive constructive architecture and lithofacies. It is the first described example of a glaciovolcano erupted beneath an ice stream. The characteristics of the second centre at Sheridan Bluff indicate that it was also a monogenetic volcano but with a shield-like profile, originally c. 6 km in basal diameter but just c. 400 m high. It probably erupted in a substantial pluvial lake in an ice-poor or ice-free environment. The strongly contrasting eruptive settings now identified by the volcanic sequences at both centres examined testify to a highly dynamic Antarctic Ice Sheet during the Early—mid Miocene.

Thermochronology as a key to deciphering controls on landscape evolution in northern Victoria Land (Transantarctic Mountains) 

2021 ◽  
Author(s):  
Daniela Roehnert ◽  
Frank Lisker ◽  
Maria Laura Balestrieri ◽  
Luca Grewe ◽  
Evandro Balbi ◽  
...  
Keyword(s):  
Fission Track ◽  
Morphological Evolution ◽  
Accelerated Cooling ◽  
Rift System ◽  
Low Grade ◽  
West Antarctic ◽  
Victoria Land ◽  
Transantarctic Mountains ◽  
West Antarctic Rift System ◽  
West Antarctic Rift

<p>Northern Victoria Land constitutes the Pacific terminus of the Transantarctic Mountains (TAM) on the western shoulder of the Cenozoic West Antarctic Rift System. It is characterised by a distinct morphological transition from an elevated peneplain that dominates throughout most of the TAM to a strongly undulating relief with prominent narrow crests and alpine peaks. This contrast is associated with a lithological change from high-grade metamorphics and granitoids to low-grade metasedimentary rocks that contain only few scattered igneous bodies.</p><p>New high-resolution thermochronological data (fission-track and (U-Th-Sm)/He) from more than 60 locations in the Southern Cross Mountains and Mountaineer Range of northern Victoria Land provide the basis for studying regional exhumation and uplift with particular focus on the establishment of landscape contrasts. In an integrated approach, differences in topography are examined with respect to regional and local controls including tectonics, lithology and climate to identify differential trends and quantify the morphological evolution of the TAM and West Antarctic Rift System.</p><p> </p><p>Two coastal profiles covering 2 to 3 km in elevation reveal apatite fission track ages from 23 to 45 Ma with mean track lengths of 13.3 – 14.7 μm. Corresponding (U-Th-Sm)/He apatite and zircon data range between 19 – 32 Ma and 24 – 27 Ma, respectively. The dates show distinctive spatial trends of increasing ages from north to south and at greater distance to the coast whereby younger cooling ages correlate with stronger terrain segmentation and higher topographic relief.</p><p>Thermal history modelling of the combined data indicates that accelerated cooling commencing at 35 Ma proceeded at progressively higher rates reaching >25°C/Ma in late stages. This cooling episode continued until at least 20 Ma and refers to exhumation from burial depths of more than 5 km, clearly exceeding the calculated overburden on adjacent crustal blocks to the south. Although rapid upper lithospheric cooling is a generic feature of northern Victoria Land, the current data demonstrates that Cenozoic exhumation dynamics were highly differential. Understanding these patterns requires thorough balancing of structural against isostatic factors, lithological against climate parameters and focussed local incision against large-scale denudation and levelling processes.</p>

Chapter 5.3b Mount Early and Sheridan Bluff: petrology

2021 ◽  
pp. M55-2019-2 ◽  
Author(s):  
Kurt S. Panter ◽  
Jenna Reindel ◽  
John L. Smellie
Keyword(s):  
Volcanic Field ◽  
Rift System ◽  
The West ◽  
Simultaneous Generation ◽  
Element Abundances ◽  
West Antarctic ◽  
Mantle Sources ◽  
West Antarctic Rift System ◽  
Ocean Ridge ◽  
West Antarctic Rift

AbstractThis study discusses the petrological and geochemical features of two monogenetic Miocene volcanoes, Mount Early and Sheridan Bluff, which are the above-ice expressions of Earth's southernmost volcanic field located at c. 87° S on the East Antarctic Craton. Their geochemistry is compared to basalts from the West Antarctic Rift System to test affiliation and resolve mantle sources and cause of melting beneath East Antarctica. Basaltic lavas and dykes are olivine-phyric and comprise alkaline (hawaiite and mugearite) and subalkaline (tholeiite) types. Trace element abundances and ratios (e.g. La/Yb, Nb/Y, Zr/Y) of alkaline compositions resemble basalts from the West Antarctic rift and ocean islands (OIB), while tholeiites are relatively depleted and approach the concentrations levels of enriched mid-ocean ridge basalt (E-MORB). The magmas evolved by fractional crystallization with contamination by crust; however, neither process can adequately explain the contemporaneous eruption of hawaiite and tholeiite at Sheridan Bluff. Our preferred scenario is that primary magmas of each type were produced by different degrees of partial melting from a compositionally similar mantle source. The nearly simultaneous generation of lower degrees of melting to produce alkaline types and higher degrees of melting forming tholeiite was most likely to have been facilitated by the detachment and dehydration of metasomatized mantle lithosphere.

Melt-modified lithosphere beneath Ross Island and its role in the tectono-magmatic evolution of the West Antarctic Rift System

2019 ◽  
Vol 518 ◽  
pp. 45-54 ◽  
Author(s):  
James M.D. Day ◽  
Ralph P. Harvey ◽  
David R. Hilton
Keyword(s):  
Rift System ◽  
Magmatic Evolution ◽  
The West ◽  
West Antarctic ◽  
West Antarctic Rift System ◽  
West Antarctic Rift

40Ar–39Ar dating of pseudotachylytes: the effect of clast-hosted extraneous argon in Cenozoic fault-generated friction melts from the West Antarctic Rift System

2004 ◽  
Vol 223 (3-4) ◽  
pp. 349-364 ◽  
Author(s):  
Gianfranco Di Vincenzo ◽  
Sergio Rocchi ◽  
Federico Rossetti ◽  
Fabrizio Storti
Keyword(s):  
Rift System ◽  
The West ◽  
West Antarctic ◽  
West Antarctic Rift System ◽  
West Antarctic Rift

scholarly journals Regional seismic stratigraphic correlations of the Ross Sea: Implications for the tectonic history of the West Antarctic Rift System

2007 ◽  
Author(s):  
Robert C. Decesari ◽  
Christopher C. Sorlien ◽  
Bruce P. Luyendyk ◽  
Douglas S. Wilson ◽  
Louis Bartek ◽  
...  
Keyword(s):  
Ross Sea ◽  
Rift System ◽  
The West ◽  
West Antarctic ◽  
Tectonic History ◽  
History Of ◽  
West Antarctic Rift System ◽  
West Antarctic Rift

Chapter 1.2 Antarctic volcanism: volcanology and palaeoenvironmental overview

2021 ◽  
pp. M55-2020-1 ◽  
Author(s):  
John L. Smellie
Keyword(s):  
Large Scale ◽  
Environmental Changes ◽  
Critical Parameters ◽  
Rift System ◽  
Mass Extinctions ◽  
Volcanic Arc ◽  
Principal Characteristics ◽  
West Antarctic ◽  
Alkaline Volcanism ◽  
Break Up

AbstractSince Jurassic time (c. 200 Ma), Antarctica has had a greater diversity of volcanism than other southern continents. It includes: (1) voluminous mafic and felsic volcanism associated with the break-up of Gondwana; (2) a long-lived continental margin volcanic arc, including back-arc alkaline volcanism linked to slab rollback; (3) small-volume mafic alkaline volcanism associated with slab-window formation; and (4) one of Earth's major continental rift zones, the West Antarctic Rift System (WARS), with its numerous large alkaline central volcanoes. Several of Antarctica's volcanoes are still active. This chapter is a review of the major volcanic episodes and their principal characteristics, in their tectonic, volcanological and palaeoenvironmental contexts. Jurassic Gondwana break-up was associated with large-scale volcanism that caused global environmental changes and associated mass extinctions. The volcanic arc was a major extensional arc characterized by alternating volcanic flare-ups and lulls. The Neogene rift-related alkaline volcanism is dominated by effusive glaciovolcanic eruptions, overwhelmingly as both pāhoehoe- and ‘a‘ā-sourced lava-fed deltas. The rift is conspicuously poor in pyroclastic rocks due to the advection and removal of tephra erupted during glacial intervals. Volcanological investigations of the Neogene volcanism have also significantly increased our knowledge of the critical parameters and development of the Antarctic Ice Sheet.

Some evidence for a wide fan-shaped extension of the East Antarctic plate at the Mesozoic-Cenozoic transition

2021 ◽  
Author(s):  
Egidio Armadillo ◽  
Daniele Rizzello ◽  
Pietro Balbi ◽  
Davide Scafidi ◽  
Andrea Zunino ◽  
...  
Keyword(s):  
Potential Field ◽  
Plate Tectonics ◽  
Rift System ◽  
Plate Deformation ◽  
Continental Scale ◽  
West Antarctic ◽  
Depositional Processes ◽  
Euler Pole ◽  
Plate Reconstructions ◽  
West Antarctic Rift System

<p>The Transantarctic Mountains (TAM) separate the Mesozoic to recent West Antarctic rift system (WARS) from a wide and depressed triangular sector of East Antarctica spanning from 100° E to 160° E in longitude and from the Oates, George V and Adelie coastlines to 85° S in latitude. The sub-ice bedrock of this sector shows a basin and range style topography comprising two major basins of continental proportions -the Wilkes Basin and the Aurora Basin complex- and many smaller basins such as the Adventure, Concordia, Aurora and Vostok trenches. Most of these basins and trenches exhibit a triangular shape with the acutest angle pointing approximatively to a single pole towards the South, giving a fan shaped pattern of significant dimensions. We name here this region as the East Antarctic Fan shaped Basin Province (EAFBP). To the West, this province is limited by the intraplate Gamburtsev Mountains (GM).</p><p>Origins and inter-relationships between these four fundamental Antarctic tectonic units (WARS, TAM, EAFBP, GM) are still poorly understood and strongly debated. In the EAFBP, very little is known about the mechanism generating the basins, their formation time, whether they are all coeval and if and how they relate to Australia basins before Antarctica-Australia rifting. Present genetic hypotheses for some of the basins span from continental rifting to a purely flexural origin or a combination of the two. Also, post-tectonic erosional and depositional processes may have had a significant impact on the present-day topographic configuration.</p><p>Here we investigate the possibility that the EAFBP is the result of a single genetic mechanism: a wide fan-shaped intra-continental extension around a pivot point at about 135° E, 85° S that occurred at the Mesozoic-Cenozoic transition. We discuss evidence from the sub-ice topography and potential field airborne and satellite data.</p><p>We have used international community-based Antarctic compilations in public domain, including BedMachine (Morlighem et al., 2020), AntGG (Scheinert et al., 2016) and ADMAP 2.0 (Golynsky et al., 2018). We have applied image segmentation techniques to the rebounded sub-ice topography to automatically trace the first order shape of the sub-ice basins. Then we have fitted the edges of the basins by maximum circles and we have estimated the best Euler pole identified by their intersection. Potential field anomalies have been taken into account in order to enlighten major discontinuities not revealed by the sub-ice topography.</p><p>Software simulations of the EAFBP opening in the frame of global plate tectonics reconstructions indicate that it may be inserted in the frame of the later phase of the Antarctica-Australia rifting, giving constraints on timing that allow us to date the EAFBP opening at the Mesozoic-Cenozoic transition.</p><p>The reconnaissance of the EAFBP as the result of a continental-scale fan-shaped extension may have deep implications on global and regional tectonics plate reconstructions, plate deformation assumptions and new tectonic evolutionary models of WARS, TAM and GM.</p>

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