scholarly journals Cenozoic magmatism in the western Ross Embayment: Role of mantle plume versus plate dynamics in the development of the West Antarctic Rift System

2002 ◽  
Vol 107 (B9) ◽  
pp. ECV 5-1-ECV 5-22 ◽  
Author(s):  
Sergio Rocchi ◽  
Pietro Armienti ◽  
Massimo D'Orazio ◽  
Sonia Tonarini ◽  
Jan R. Wijbrans ◽  
...  
Keyword(s):  
Mantle Plume ◽  
Rift System ◽  
The West ◽  
West Antarctic ◽  
Plate Dynamics ◽  
West Antarctic Rift System ◽  
West Antarctic Rift ◽  
Cenozoic Magmatism

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.

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.

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

Hobbs Coast Cenozoic volcanism: Implications for the West Antarctic rift system

1997 ◽  
Vol 139 (1-4) ◽  
pp. 223-248 ◽  
Author(s):  
Stanley R. Hart ◽  
Jerzy Blusztajn ◽  
Wesley E. LeMasurier ◽  
David C. Rex
Keyword(s):  
Rift System ◽  
The West ◽  
West Antarctic ◽  
Cenozoic Volcanism ◽  
West Antarctic Rift System ◽  
West Antarctic Rift
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